Choose what to find, then enter the lot and building areas in square meters. For the limits in %, enter the values set by your local zoning rules.
In the maximum area mode, the current footprint and floor area can be left blank. If you enter them, the room left under the limits (how many more m² you can build) is shown too.
Result and figure
Enter the lot area and the building areas in the fields on the left and press "Calculate". The result will appear here.
Table of Contents
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What you can do on this page
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What is this calculation used for?
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How to Use
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Formulas and figures
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Symbols and terms
-
Good to know before you start
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How to calculate it in Excel
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How to calculate it in Google Sheets
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How to calculate it in Python
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How to write it in LaTeX and other math languages (copy and paste)
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How to have ChatGPT do the calculation
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DataChef Features
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Related Features
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NumberChef Calculators List
What you can do on this page
- Enter the lot area, the building footprint and the gross floor area, and you get the lot coverage (footprint ÷ lot area) and the floor area ratio, FAR (floor area ÷ lot area), in %
- You can enter areas in square feet or in acres (acres are converted with 1 acre = 43,560 ft²). Switch "Units" to Metric to work in square meters
- Working backward, enter the lot area and the lot coverage and FAR limits in %, and you get the maximum footprint and maximum floor area for that lot, plus an estimate of the number of stories (maximum floor area ÷ maximum footprint)
- Add the footprint and floor area of the existing building, and you also see the room left under the limits (how many more square feet you can build) and the current ratios
- A figure shows how much of the lot the footprint covers
In the US, the lot coverage and FAR limits are set by your city or county zoning code and differ from one zoning district to another. Enter the values for your lot (from the zoning code, the zoning map or the property listing). How areas are counted also differs by place (for example, some codes count driveways and patios toward lot coverage, and some leave basements or garages out of the floor area), and this page does not handle those rules. The maximum areas here are simply "the areas the limits you entered allow". Setbacks, height limits and other rules can make what you can actually build smaller. Always confirm with your local planning or zoning office, or with an architect.
What is this calculation used for?
Sizing up how big a house a lot can hold
Say a listing shows a 5,000 ft² lot in a district where, for example, the zoning code allows 40% lot coverage and an FAR of 0.6. That alone tells you the footprint can be up to \(5000 \times 0.4 = 2000\) ft² and the floor area up to \(5000 \times 0.6 = 3000\) ft².
Compare this with the home you want, say 2,400 ft² of living space, and you can tell whether the lot is big enough before you visit. The exact limits depend on local rules on what counts, so confirm them with the planning office or an architect in the end.
Checking how much you can add before an addition or a rebuild
On a 6,000 ft² lot with limits of 35% lot coverage and 50% FAR, a house with a 1,800 ft² footprint and 2,600 ft² of floor area has \(2100 - 1800 = 300\) ft² of footprint and \(3000 - 2600 = 400\) ft² of floor area left.
A 12 ft × 20 ft (240 ft²) family room on the ground floor fits both margins on paper, but a 20 ft × 20 ft (400 ft²) ground-floor addition goes over the 300 ft² of footprint left. It is a quick check before you hire a designer (whether you can really build it also depends on setbacks, height limits and the structure, so ask an architect).
Seeing how much ground is left for a yard and parking
The lot coverage share goes to buildings, and the rest is left for a yard, a driveway and paths. On a 4,000 ft² lot with a 50% lot coverage limit, the house can cover up to 2,000 ft², leaving 2,000 ft² of open ground.
A standard parking space is about \(9 \times 18 = 162\) ft², so two cars need about 324 ft². That tells you whether "two parking spaces plus a yard" will fit. If your code also limits hard surfaces such as driveways, check that limit too.
Understanding the lot coverage and FAR in zoning rules
Two 5,000 ft² lots can allow very different buildings. With a 40% lot coverage limit and FAR 0.8, the maximum floor area is 4,000 ft². With an 80% lot coverage limit and FAR 4.0, it is 20,000 ft².
The FAR divided by the lot coverage (\(0.8 \div 0.4 = 2\), \(4.0 \div 0.8 = 5\)) is the number of stories that fit when the footprint uses the full lot coverage. It tells you whether an area is meant for low buildings or tall ones.
Planning a multigenerational home or a home with a rental unit
Say you want 1,400 ft² for each of two households, 2,800 ft² in total, on a 5,000 ft² lot with a 30% lot coverage limit. The footprint can be up to 1,500 ft², so you need \(2800 \div 1500 \approx 1.87\) stories, which means a two-story house.
With an FAR limit of 0.6, the maximum floor area is 3,000 ft² and 2,800 ft² fits. With an FAR limit of 0.5, it is only 2,500 ft² on paper, so the plan needs to change.
Formulas and figures
Lot coverage
Figure
Standard notation
(the usual math form)
\(C\)
\(=\)
\(B\)
\(\div\)
\(S\)
\(\times\)
\(100\)
In words
(symbols replaced with words)
③
\(C\): lot coverage
\(=\)
①
\(B\): footprint
\(\div\)
②
\(S\): lot area
\(\times\)
\(100\)
The formula in words
①
Take the
\(B\): footprint
②
divide it by the
\(S\): lot area
and multiply by 100 to get a percentage
③
and you get the
\(C\): lot coverage
Quick example
The lot coverage of a 4,000 ft² lot (40 ft × 100 ft) with a house whose footprint (the area seen from above) is 2,000 ft² is
\(C\): lot coverage
\(=\)
footprint (2,000 ft²)
\(\div\)
lot area (4,000 ft²)
\(\times\)
\(100\)
\(2000 \div 4000 \times 100 = 0.5 \times 100 = 50\ (\%)\)
Key idea
Lot coverage is the share of the lot that is covered by buildings. The footprint on top of the fraction is the area of the building seen from directly above (its horizontal projection). It is often about the same as the first-floor area, but if the second floor sticks out past the first, the overhang counts too.
The lower the lot coverage, the more ground is left for a yard, a driveway and paths. In the example, the house covers 2,000 ft² of the 4,000 ft² lot, so the other 2,000 ft² is open ground. Many zoning codes also count garages, sheds and decks, and some count driveways and patios as well (often called impervious coverage), so check what your code includes.
If you enter the areas in acres, they are converted with 1 acre = 43,560 ft² first. Because this is a ratio, you get the same answer in any unit as long as the top and the bottom use the same unit.
Floor area ratio (FAR)
Figure
Standard notation
(the usual math form)
\(V\)
\(=\)
\(F\)
\(\div\)
\(S\)
\(\times\)
\(100\)
In words
(symbols replaced with words)
③
\(V\): FAR
\(=\)
①
\(F\): gross floor area
\(\div\)
②
\(S\): lot area
\(\times\)
\(100\)
The formula in words
①
Take the
\(F\): gross floor area
②
divide it by the
\(S\): lot area
and multiply by 100 to get a percentage
③
and you get the
\(V\): FAR
Quick example
The FAR of a 4,000 ft² lot with a house of 2,000 ft² on the first floor + 2,000 ft² on the second + 1,000 ft² on the third (5,000 ft² of floor area) is
\(V\): FAR
\(=\)
floor area (5,000 ft²)
\(\div\)
lot area (4,000 ft²)
\(\times\)
\(100\)
\(5000 \div 4000 \times 100 = 1.25 \times 100 = 125\ (\%)\)
Key idea
FAR is the total floor space compared with the size of the lot. It uses the gross floor area, which is all the stories added together. The more stories you stack, the larger the floor area, so the FAR can go over 100%. The 125% in the example says there is 1.25 times as much floor as there is lot. In US zoning codes, FAR is usually written as a ratio, so 125% is the same as "FAR 1.25", and "FAR 0.6" is 60%.
Lot coverage controls how much of the ground a building may cover, and FAR controls how much floor space it may have in total. Put the two together, and you can see the largest building the lot allows (next formula).
Maximum footprint and maximum floor area (working backward)
Standard notation
(the usual math form)
\(B_{\max}\)
\(=\)
\(S\)
\(\times\)
\(C_{\max}\)
\(\div\)
\(100\)
\(F_{\max}\)
\(=\)
\(S\)
\(\times\)
\(V_{\max}\)
\(\div\)
\(100\)
In words
(symbols replaced with words)
④
\(B_{\max}\): maximum footprint
\(=\)
①
\(S\): lot area
\(\times\)
②
\(C_{\max}\): lot coverage limit
\(\div\)
\(100\)
\(F_{\max}\): maximum floor area
\(=\)
\(S\): lot area
\(\times\)
③
\(V_{\max}\): FAR limit
\(\div\)
\(100\)
The formula in words
①
Take the
\(S\): lot area
②
multiply it by the
\(C_{\max}\): lot coverage limit
and divide by 100 (to turn the percentage back into a ratio) to get the maximum footprint. In the same way,
③
multiply the lot area by the
\(V_{\max}\): FAR limit
and divide by 100 to get the maximum floor area. So the
④
\(B_{\max}\): maximum footprint and \(F_{\max}\): maximum floor area
are the lot area times each limit as a ratio
Quick example
For a 5,000 ft² lot where, for example, the lot coverage limit is 40% and the FAR limit is 60% (FAR 0.6), the largest areas you can build are
\(B_{\max}\): maximum footprint
\(=\)
lot area (5,000 ft²)
\(\times\)
lot coverage limit (40%)
\(\div\)
\(100\)
\(F_{\max}\): maximum floor area
\(=\)
lot area (5,000 ft²)
\(\times\)
FAR limit (60%)
\(\div\)
\(100\)
\(5000 \times 40 \div 100 = 2000\ \mathrm{ft^2}\)
\(5000 \times 60 \div 100 = 3000\ \mathrm{ft^2}\)
Key idea
These are the lot coverage and FAR formulas rewritten as "area =". If buildings may cover up to 40% of the lot, the footprint limit is 5,000 ft² × 0.4 = 2,000 ft². If the FAR is 0.6, the floor area limit is 5,000 ft² × 0.6 = 3,000 ft². This is the basic calculation for sizing up "how big a house can go on this lot" when you look at land or plan a rebuild.
In the US, the limits are set by the city or county zoning code for each zoning district, and they vary a lot from place to place. The numbers above are only an example. Codes also differ in what they count: some include decks, sheds or driveways in lot coverage, and some leave basements, attics or garages out of the floor area. Setbacks (the required distance from the lot lines), height limits and other rules can also make the real maximum smaller than this calculation. Treat the answer as "the areas the limits you entered allow", and confirm the actual limits with your planning or zoning office or an architect.
Estimated number of stories
Standard notation
(the usual math form)
\(n\)
\(=\)
\(F\)
\(\div\)
\(B\)
In words
(symbols replaced with words)
③
\(n\): estimated stories
\(=\)
①
\(F\): gross floor area
\(\div\)
②
\(B\): footprint
The formula in words
①
Take the
\(F\): gross floor area
②
divide it by the
\(B\): footprint
③
and you get the
\(n\): estimated stories
(how many times the footprint the floor area is)
Quick example
For the house in the earlier example, with a 2,000 ft² footprint and 5,000 ft² of floor area, the estimated number of stories is
\(n\): estimated stories
\(=\)
floor area (5,000 ft²)
\(\div\)
footprint (2,000 ft²)
\(5000 \div 2000 = 2.5\)
Key idea
This is the number of stories you would get if every story were as large as the footprint. A value of 2.5 tells you that a two-story house would leave some floor area unused, and a three-story house would have a third floor about half the size of the others. A value of exactly 2 is a full two-story house, with both floors the same size. In the maximum area mode it is the maximum floor area ÷ the maximum footprint, which is \(V_{\max} \div C_{\max}\) (for example, 60% ÷ 40% = 1.5). It shows how many stories fit under the FAR limit when the footprint uses the full lot coverage.
The real number of stories depends on how each floor is laid out, height limits and other rules, so this is only a rough guide.
Room left under the limits (how many more square feet you can build)
Standard notation
(the usual math form)
\(\Delta B\)
\(=\)
\(B_{\max}\)
\(-\)
\(B\)
\(\Delta F\)
\(=\)
\(F_{\max}\)
\(-\)
\(F\)
In words
(symbols replaced with words)
③
\(\Delta B\): footprint left
\(=\)
①
\(B_{\max}\): maximum footprint
\(-\)
②
\(B\): current footprint
\(\Delta F\): floor area left
\(=\)
\(F_{\max}\): maximum floor area
\(-\)
\(F\): current floor area
The formula in words
①
Take the
\(B_{\max}\): maximum footprint
②
subtract the
\(B\): current footprint
③
and you get the
\(\Delta B\): footprint left
. In the same way, the maximum floor area \(F_{\max}\) minus the current floor area \(F\) is the floor area left \(\Delta F\)
Quick example
On a 6,000 ft² lot with limits of 35% lot coverage and 50% FAR (maximum footprint 2,100 ft², maximum floor area 3,000 ft²), a house with a 1,800 ft² footprint and 2,600 ft² of floor area has this much room left
\(\Delta B\): footprint left
\(=\)
maximum footprint (2,100 ft²)
\(-\)
current footprint (1,800 ft²)
\(\Delta F\): floor area left
\(=\)
maximum floor area (3,000 ft²)
\(-\)
current floor area (2,600 ft²)
\(2100 - 1800 = 300\ \mathrm{ft^2}\)
\(3000 - 2600 = 400\ \mathrm{ft^2}\)
Key idea
This is the "how much more can I build" calculation for an addition or a rebuild. In the example, a ground-floor addition can be up to 300 ft², and new floor space can total up to 400 ft². A room added on top of the existing first floor does not change the footprint, so only the 400 ft² of floor area left matters. Which margin limits you depends on how you add on.
If a margin comes out negative, the current areas you entered are over the limit. This can happen when the rules changed after the house was built (a "legal nonconforming" building) or when areas are counted differently, so do not treat it as the final word. Check with your planning or zoning office or an architect.
Lot coverage is "footprint ÷ lot area × 100", and FAR is "gross floor area ÷ lot area × 100". Working backward, multiply the lot area by each limit as a ratio to get the maximum footprint and the maximum floor area for the lot. Use the limits in your local zoning code, and check with your planning or zoning office or an architect on how areas are counted.
Symbols and terms
Symbols
| \(S\) | S | The lot area (the area of the land the building stands on), from "site". It is calculated in ft² (areas entered in acres are converted to ft²). |
| \(B\) | B | The building footprint (the area seen from directly above), from "building". In the maximum area mode it is the current footprint. |
| \(F\) | F | The gross floor area (all stories added together), from "floor". In the maximum area mode it is the current floor area. |
| \(C\) | C | The lot coverage in %, from "coverage". Found with \(C = B \div S \times 100\). |
| \(V\) | V | The floor area ratio (FAR) in %. The letter comes from "volume", since FAR controls the bulk of a building, but it is calculated from floor area, not volume. Found with \(V = F \div S \times 100\). |
| \(C_{\max}\), \(V_{\max}\) | C max, V max | The lot coverage and FAR limits in %. "max" is short for maximum. Enter the values in your local zoning code. |
| \(B_{\max}\), \(F_{\max}\) | B max, F max | The maximum footprint and maximum floor area found backward from the limits. Found with \(B_{\max} = S \times C_{\max} \div 100\) and \(F_{\max} = S \times V_{\max} \div 100\). |
| \(n\) | n | The estimated number of stories, from "number". It is the floor area ÷ the footprint: the number of stories if every story were as large as the footprint. |
| \(\Delta B\), \(\Delta F\) | delta B, delta F | The room left under the limits (how many more square feet you can build). \(\Delta\) (delta) is the Greek letter used for "difference". Found with \(\Delta B = B_{\max} - B\) and \(\Delta F = F_{\max} - F\). |
Terms
| lot coverage | The building footprint as a percentage of the lot area. It shows how much of the lot may be covered by buildings. Limits are set to keep light, air, open space and room for rainwater to soak into the ground. Some codes use "building coverage" for this. |
| floor area ratio | The gross floor area divided by the lot area, usually shortened to FAR. It shows how much floor space may be built on the lot, and limits keep the size and density of buildings in check. US codes usually write it as a ratio (FAR 0.6); this page uses the same value in % (60%). Because stories stack up, it can go above 1 (100%). |
| lot area | The area of the land the building stands on, shown as the "lot size" in property listings and records. It is the bottom of the fraction in both lot coverage and FAR. |
| footprint | The area inside the outline of the building seen from directly above (its horizontal projection). It is often about the same as the first-floor area, but a second floor that sticks out past the first also counts. |
| gross floor area | The floor areas of all stories added together. For a two-story house, it is the first-floor area plus the second-floor area. Also called total floor area. |
| horizontal projection | The shadow a building would cast on the ground if lit from directly above, in other words "the area seen from above". The footprint is measured this way. |
| zoning district | An area on the local zoning map with its own rules on what kind and size of building may be built (residential, commercial, industrial and so on). The lot coverage and FAR limits are set for each district. You can find your district on the city or county zoning map or at the planning office. |
| zoning code | The local law (also called a zoning ordinance) in which a city or county sets how land may be used and how large buildings may be. The lot coverage and FAR limits for each zoning district are written in it. |
| setback | The minimum distance a building must keep from the front, side and rear lot lines. Even when lot coverage and FAR allow more, setbacks can make the buildable area smaller. This page does not calculate setbacks. |
| impervious coverage | The share of a lot covered by hard surfaces that water cannot soak through, such as buildings, driveways and patios. Some codes limit this separately from lot coverage, or count these surfaces in lot coverage. This page does not handle these rules. |
| full two-story | A two-story house whose second floor is the same size as the first, like a simple box. The floor area is the footprint × 2, so the estimated number of stories is exactly 2. |
| acre | A unit of land area used in the US. 1 acre = 43,560 ft² (about 4,047 m²). Larger lots are often listed in acres, such as "0.25 acres" (10,890 ft²). |
Good to know before you start
Here is what helps you use the calculation on this page with real understanding, not just by pressing the button.
| Ratios and percentages (Grades 6–7) |
|
| Area and its units (Grades 3–6) |
|
| Converting units (Grades 5–7 and up) |
|
| Multiplying and dividing decimals (Grades 5–6) |
|
How to calculate it in Excel
Copy the whole table below and paste it into cell A1 in Excel. It works as is.
Table to find the lot coverage
| Lot area (ft²) | 4000 |
| Footprint (ft²) | 2000 |
| Lot coverage (%) | =B2/B1*100 |
Table to find the FAR
| Lot area (ft²) | 4000 |
| Gross floor area (ft²) | 5000 |
| FAR (%) | =B2/B1*100 |
Table to find the maximum footprint and maximum floor area
| Lot area (ft²) | 5000 |
| Lot coverage limit (%) | 40 |
| FAR limit (%) | 60 |
| Maximum footprint (ft²) | =B1*B2/100 |
| Maximum floor area (ft²) | =B1*B3/100 |
Table to find the estimated number of stories
| Gross floor area (ft²) | 5000 |
| Footprint (ft²) | 2000 |
| Estimated stories | =B1/B2 |
Table to find the room left under the limits
| Maximum footprint (ft²) | 2100 |
| Current footprint (ft²) | 1800 |
| Maximum floor area (ft²) | 3000 |
| Current floor area (ft²) | 2600 |
| Footprint left (ft²) | =B1-B2 |
| Floor area left (ft²) | =B3-B4 |
After pasting, the upper rows in column B are your inputs and the last rows are calculated automatically.
"/" is division and "*" is multiplication. B3 in the first table shows 50 (%), and B3 in the second table shows 125 (%).
The third table turns the % back into a ratio with "/100" before multiplying by the lot area (B4 shows 2000 and B5 shows 3000). If your code gives the FAR as a ratio such as 0.6, enter 60 in B3.
B3 in the fourth table shows 2.5, and the fifth table shows 300 in B5 and 400 in B6. To enter an area in acres, type it in the cell as "=0.25*43560" and it is converted to ft².
"/" is division and "*" is multiplication. B3 in the first table shows 50 (%), and B3 in the second table shows 125 (%).
The third table turns the % back into a ratio with "/100" before multiplying by the lot area (B4 shows 2000 and B5 shows 3000). If your code gives the FAR as a ratio such as 0.6, enter 60 in B3.
B3 in the fourth table shows 2.5, and the fifth table shows 300 in B5 and 400 in B6. To enter an area in acres, type it in the cell as "=0.25*43560" and it is converted to ft².
How to calculate it in Google Sheets
Copy the whole table below and paste it into cell A1 in Google Sheets. It works as is.
Table to find the lot coverage
| Lot area (ft²) | 4000 |
| Footprint (ft²) | 2000 |
| Lot coverage (%) | =B2/B1*100 |
Table to find the FAR
| Lot area (ft²) | 4000 |
| Gross floor area (ft²) | 5000 |
| FAR (%) | =B2/B1*100 |
Table to find the maximum footprint and maximum floor area
| Lot area (ft²) | 5000 |
| Lot coverage limit (%) | 40 |
| FAR limit (%) | 60 |
| Maximum footprint (ft²) | =B1*B2/100 |
| Maximum floor area (ft²) | =B1*B3/100 |
Table to find the estimated number of stories
| Gross floor area (ft²) | 5000 |
| Footprint (ft²) | 2000 |
| Estimated stories | =B1/B2 |
Table to find the room left under the limits
| Maximum footprint (ft²) | 2100 |
| Current footprint (ft²) | 1800 |
| Maximum floor area (ft²) | 3000 |
| Current floor area (ft²) | 2600 |
| Footprint left (ft²) | =B1-B2 |
| Floor area left (ft²) | =B3-B4 |
The same formulas as in Excel work as is. Copy the whole table, paste it into cell A1, and replace the numbers in column B with your own.
How to calculate it in Python
site_area = 4000.0 # lot area (ft²). For acres, convert like 0.25 * 43560
building_area = 2000.0 # building footprint (ft²)
floor_area = 5000.0 # gross floor area (ft²)
# lot coverage and FAR (%), and the estimated number of stories
coverage_ratio = building_area / site_area * 100
floor_area_ratio = floor_area / site_area * 100
floors_estimate = floor_area / building_area
print(f"Lot coverage: {coverage_ratio:.2f} %")
print(f"FAR: {floor_area_ratio:.2f} %")
print(f"Estimated stories: {floors_estimate:.2f}")
# working backward: maximum areas from the limits, and the room left for the current building
coverage_limit = 60.0 # lot coverage limit (%), from your local zoning code
far_limit = 150.0 # FAR limit (%); FAR 1.5 = 150 %
max_building_area = site_area * coverage_limit / 100
max_floor_area = site_area * far_limit / 100
building_margin = max_building_area - building_area
floor_margin = max_floor_area - floor_area
print(f"Maximum footprint: {max_building_area:.2f} ft² (room left {building_margin:.2f} ft²)")
print(f"Maximum floor area: {max_floor_area:.2f} ft² (room left {floor_margin:.2f} ft²)")
Runs with the standard library only. Replace the areas at the top and the limits in % with your own numbers and run it. If a "room left" value is negative, the current area is over the limit.
How to write it in LaTeX and other math languages (copy and paste)
Lot coverage
C = B ÷ S × 100
C = \frac{B}{S} \times 100
<math xmlns="http://www.w3.org/1998/Math/MathML" display="block">
<mrow>
<mi>C</mi>
<mo>=</mo>
<mfrac><mi>B</mi><mi>S</mi></mfrac>
<mo>×</mo>
<mn>100</mn>
</mrow>
</math>
C = B / S xx 100
b/s*100
C := B/S*100;
C = B/S*100;
C = B/S × 100
Floor area ratio (FAR)
V = F ÷ S × 100
V = \frac{F}{S} \times 100
<math xmlns="http://www.w3.org/1998/Math/MathML" display="block">
<mrow>
<mi>V</mi>
<mo>=</mo>
<mfrac><mi>F</mi><mi>S</mi></mfrac>
<mo>×</mo>
<mn>100</mn>
</mrow>
</math>
V = F / S xx 100
f/s*100
V := F/S*100;
V = F/S*100;
V = F/S × 100
Maximum footprint and maximum floor area (working backward)
Bmax = S × Cmax ÷ 100, Fmax = S × Vmax ÷ 100
B_{\max} = S \times \frac{C_{\max}}{100},\quad F_{\max} = S \times \frac{V_{\max}}{100}
<math xmlns="http://www.w3.org/1998/Math/MathML" display="block">
<mrow>
<msub><mi>B</mi><mi>max</mi></msub>
<mo>=</mo>
<mi>S</mi><mo>×</mo>
<mfrac><msub><mi>C</mi><mi>max</mi></msub><mn>100</mn></mfrac>
<mo>,</mo>
<msub><mi>F</mi><mi>max</mi></msub>
<mo>=</mo>
<mi>S</mi><mo>×</mo>
<mfrac><msub><mi>V</mi><mi>max</mi></msub><mn>100</mn></mfrac>
</mrow>
</math>
B_max = S xx C_max / 100, F_max = S xx V_max / 100
{s*cmax/100, s*vmax/100}
Bmax := S*Cmax/100; Fmax := S*Vmax/100;
Bmax = S*Cmax/100; Fmax = S*Vmax/100;
B_max = S × C_max/100, F_max = S × V_max/100
Estimated number of stories
n = F ÷ B
n = \frac{F}{B}
<math xmlns="http://www.w3.org/1998/Math/MathML" display="block">
<mrow>
<mi>n</mi>
<mo>=</mo>
<mfrac><mi>F</mi><mi>B</mi></mfrac>
</mrow>
</math>
n = F / B
f/b
n := F/B;
n = F/B;
n = F/B
Room left under the limits (how many more square feet you can build)
ΔB = Bmax − B, ΔF = Fmax − F
\Delta B = B_{\max} - B,\quad \Delta F = F_{\max} - F
<math xmlns="http://www.w3.org/1998/Math/MathML" display="block">
<mrow>
<mi>Δ</mi><mi>B</mi>
<mo>=</mo>
<msub><mi>B</mi><mi>max</mi></msub>
<mo>−</mo>
<mi>B</mi>
<mo>,</mo>
<mi>Δ</mi><mi>F</mi>
<mo>=</mo>
<msub><mi>F</mi><mi>max</mi></msub>
<mo>−</mo>
<mi>F</mi>
</mrow>
</math>
Delta B = B_max - B, Delta F = F_max - F
{bmax - b, fmax - f}
dB := Bmax - B; dF := Fmax - F;
dB = Bmax - B; dF = Fmax - F;
ΔB = B_max − B, ΔF = F_max − F
How to have ChatGPT do the calculation
You are an assistant for house and lot area calculations. Do the following calculation by actually running Python code, and base your answer only on the numbers from the execution result (do not answer by mental math or guessing). A 4,000 ft² lot has a house with a 2,000 ft² footprint and 5,000 ft² of gross floor area. Find each of the following: 1. The lot coverage (footprint ÷ lot area × 100) 2. The floor area ratio, FAR (gross floor area ÷ lot area × 100) 3. The estimated number of stories (floor area ÷ footprint) 4. If the lot coverage limit is 60% and the FAR limit is 150% (FAR 1.5), the maximum footprint and maximum floor area, and the room left for the current house (maximum − current) Show the formulas you used and the numbers from the execution result. Do not apply any local exceptions or exclusions.
How to Use
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1Enter your numbersType the numbers you want to calculate with into the input fields
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2CalculatePress the "Calculate" button
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3Check the resultThe result appears on the spot. The same page also explains the idea behind the calculation and the formula
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