Choose paving or a wall, then enter the area (or the length and height), the brick size, the joint width and the waste factor. The bricks per pallet, price, mortar bag and bricks you have can be left blank (then they are not calculated).
Table of Contents
-
What you can do on this page
-
What is this calculation used for?
-
How to Use
-
Formulas and figures
-
Symbols and terms
-
Good to know before you start
-
How to calculate it in Excel
-
How to calculate it in Google Sheets
-
How to calculate it in Python
-
How to write it in LaTeX and other math languages (copy and paste)
-
How to have ChatGPT do the calculation
-
DataChef Features
-
Related Features
-
NumberChef Calculators List
What you can do on this page
- For paving (paths, patios, the floor of a garden bed), enter the area (length × width, square feet or a circle), the brick size, how the bricks lie and the joint width, and you get the number of bricks on the spot
- For a wall (garden bed edges, low walls), the page finds the bricks per course, the number of courses and the total from the length and height (or the courses)
- Choose a modular brick (7-5/8 × 3-5/8 × 2-1/4 in) or a firebrick (9 × 4-1/2 × 2-1/2 in) from the list, or type in the size of used or other bricks
- At the same time you get the bricks needed with waste (breakage, cuts and spares), the number of pallets, the joint mortar (ft³, pounds and bags), and an estimated cost if you enter a price
- Enter the bricks you have, and you also find the area you can pave or the length of wall you can build with them
What is this calculation used for?
For example, the edge around a 5 × 3 ft garden bed is 16 ft (192 in) long. With modular bricks and 3/8 in joints, each course takes \(\lceil 192 \div 8 \rceil = 24\) bricks, 3 courses (about 7-7/8 in high) take 72 net, and with a 5% waste factor you need \(\lceil 72 \times 1.05 \rceil = 76\) bricks.
A bed has four corners where bricks are cut or offset, so buying a few extra keeps the work from stopping. You can work out the soil to fill it with the "Soil Calculator".
A path 2 ft wide and 12 ft long (24 ft²) laid flat with 1/8 in sand joints gives an area per brick of \(7.75 \times 3.75 \approx 29.06\) in², so the net count is \(24 \times 144 \div 29.06 \approx 118.9\), and with a 5% waste factor, \(\lceil 24 \times 144 \times 1.05 \div 29.06 \rceil = 125\) bricks.
A path is narrow, so the edges make up a large share and you cut bricks more often. For a curved path, a waste factor closer to 10% is safer.
A 10 × 6 ft (60 ft²) patio of modular bricks laid flat with 3/8 in joints takes 270 net, or 284 with a 5% waste factor, and about 1.53 ft³ of joint mortar. The same area with the bricks on end (the 3-5/8 × 2-1/4 in face up) gives an area per brick of \(4 \times 2.625 = 10.5\) in², so the net count is \(60 \times 144 \div 10.5 \approx 823\), more than three times as many.
The larger the area, the more the way the bricks lie affects the count and the cost, so compare both the look and the numbers before you decide.
For a firebox wall 5 ft (60 in) long and 18 in high in firebrick (9 × 4-1/2 × 2-1/2 in) with 1/8 in joints, each course takes \(\lceil 60 \div 9.125 \rceil = 7\) bricks and the courses are \(\lceil 18 \div 2.625 \rceil = 7\), so 49 net, or 54 with a 10% waste factor.
Firebrick costs more per brick than common brick, so an accurate count goes straight into the cost. For the refractory mortar and how to use it, follow the product instructions.
A contractor's estimate lists quantities such as "brick paving 60 sq ft" or "brick edging 10 LF × 4 courses". Knowing these formulas, you can follow which sizes and which waste factor the brick count came from, and sort out what to ask in the meeting. (A real estimate also includes the gravel base, bedding sand, mortar and labor, so the brick count alone cannot tell you whether the price is fair.)
When volunteers build garden beds at a school or park, working out the bricks in advance helps with budget requests and cuts down on supply runs. For example, a bed 26 ft around with a 2-course edge takes \(\lceil 312 \div 8 \rceil = 39\) bricks per course × 2 = 78 net, or 82 with a 5% waste factor.
If bricks are left from last time, following the formula backward tells you how long an edge they will make. For example, 40 bricks in 2 courses is 20 per course, and at an 8 in horizontal pitch that is 160 in, about 13.3 ft of edging.
Formulas and figures
Symbols and terms
Symbols
| \(l\) | el | The brick length (the longest side), from the first letter of "length". 7-5/8 in (7.625 in) for a modular brick. |
| \(w\) | double-u | The brick width (the shorter side seen from above), from the first letter of "width". 3-5/8 in for a modular brick. |
| \(h\) | aitch | The brick height (thickness), from the first letter of "height". 2-1/4 in for a modular brick. |
| \(p,\ q\) | pee, cue | The long and short sides of the face (the side on top when paving, or on the front of a wall). Which two of \(l, w, h\) they are depends on how the brick lies (laid flat, \(p = l,\ q = w\)). |
| \(g\) | gee | The joint width (the gap between bricks), from the first letter of "gap". 0 to 1/8 in for sand joints, 3/8 in for mortar joints. |
| \(a\) | ay | The area per brick with joint, found with \(a = (p+g)(q+g)\). From the first letter of "area". |
| \(S\) | ess | The paving area (the size of the path, patio or bed floor), given as length × width, total area (ft²) or the diameter of a circle. |
| \(r\) | ar | The waste factor, the extra for breakage, cuts and spares. In the formulas it is a decimal (0.05 for 5%) applied as "1 + r". From the first letter of "rate". |
| \(N_{0}\) | N sub zero | The net bricks (without waste). \(S \div a\) for paving and \(n \times C\) for a wall. |
| \(N\) | en | The bricks needed with waste, found with \(N = \lceil N_{0}(1+r) \rceil\). From the first letter of "number". |
| \(L\) | capital el | The wall length (for a garden bed edge, the total around the bed). |
| \(H\) | capital aitch | The wall height. It is not used when you enter the courses directly. |
| \(n\) | small en | The bricks per course, found with \(n = \lceil L \div (l+g) \rceil\). |
| \(C\) | see | The number of courses, found with \(C = \lceil H \div (h+g) \rceil\) or entered directly. From the first letter of "course". |
| \(t\) | tee | The joint depth, which is the depth of the brick (the dimension that does not show). The height \(h\) when laid flat, the width \(w\) in a wall. From the first letter of "thickness". |
| \(V\) | vee | The joint mortar (volume), found with \(V = N_{0}(a - pq)t\). From the first letter of "volume". |
| \(k\) | kay | The bricks per pallet. |
| \(B\) | bee | The pallets needed, found with \(B = \lceil N \div k \rceil\). From the first letter of "bundle". |
| \(u\) | you | The brick price (per brick or per pallet), from the first letter of "unit price". |
| \(Q\) | capital cue | The quantity that matches the price unit (bricks or pallets), from the first letter of "quantity". |
| \(T\) | capital tee | The estimated cost (bricks only), from the first letter of "total". |
| \(\lceil x \rceil\) | ceiling of x | The symbol for rounding up to a whole number, called the ceiling function. (Example - \(\lceil 283.5 \rceil = 284\), \(\lceil 4 \rceil = 4\)) |
Terms
| brick | A building unit of fired clay. The common US size is the modular brick, 7-5/8 × 3-5/8 × 2-1/4 in (8 × 4 × 2-2/3 in nominal with a 3/8 in joint), used for garden edges, paths, patios and walls. Paving bricks (pavers) are often a full 4 × 8 in, and used or imported bricks vary, so measure them and enter the size. |
| firebrick | A brick made to stand high heat, used for pizza ovens, barbecue pits, fire pits and around wood stoves. The standard size is 9 × 4-1/2 × 2-1/2 in (the "9-inch straight"), a little larger than a common brick, so choose the right size when counting. |
| joint | The gap between bricks. Mortar joints are about 3/8 in, and sand joints (bricks laid tight with sand swept in) are 0 to 1/8 in. The joint makes each brick take a little more area, so the count goes down slightly. |
| face | The side of the brick that shows, on top when paving or on the front of a wall. Which side shows depends on how the brick lies. |
| laid flat | Paving with the largest face (length × width, 7-5/8 × 3-5/8 in) on top. Each brick covers the most area, so the same area takes the fewest bricks. This is the most common way for paths and patios. |
| laid on edge | Paving with the brick on its long edge, showing the length × height face (7-5/8 × 2-1/4 in). The narrow faces are used for path borders and accent patterns, and a paving laid on edge is also very strong. |
| laid on end | Setting the brick upright with the smallest face (width × height, 3-5/8 × 2-1/4 in) on top. It is often used for a garden bed edge of bricks standing in a row (a soldier course edging), and takes the most bricks for the same area. |
| running bond | The most basic pattern, with each row offset by half a brick. The joints do not line up, which makes it strong, and the other half of a brick cut at the end can start the next row, so there is little waste. The figures on this page use this pattern. |
| herringbone | A pattern of bricks set at right angles to each other in a zigzag (like a fish skeleton). It looks striking, but the edges need many 45° cuts, so allow 10 to 15% waste. |
| basket weave | A pattern of pairs of bricks laid alternately across and along, like a woven basket. It works because two brick widths plus a joint equal about one brick length (for pavers, a full 4 × 8 in fits exactly). The waste is about the same as running bond. |
| sand joint | Laying bricks tight (or with a gap of up to about 1/8 in) and sweeping fine sand (such as polymeric sand) into the joints. With no mortar, it is easy to redo or replace bricks, but weeds and settling happen more easily. |
| mortar joint | Filling the gap between bricks (about 3/8 in) with mortar to set them. Walls are always built this way, with each course set on a bed of mortar and the head joints filled too. The joint mortar can be estimated with the formula on this page. |
| waste factor | The extra, in percent, for cuts, cut-offs, breakage and spares on top of the net amount. 5 to 10% is common, and 10 to 15% for angled patterns or shapes with many corners. |
| cut-off | The leftover piece when a brick is cut to fit at an edge or corner. How much there is depends on the pattern and shape, and not all of it can be used again, so it is covered by the waste factor. |
| net | The bare minimum amount, without waste or spares. On this page, "paving area ÷ area per brick" and "bricks per course × courses" are the net counts. |
| course | One horizontal row of bricks in a wall. A garden edge "4 courses high" is 4 rows stacked (about 10-1/2 in with modular bricks and joints). |
| mixed mortar | Mortar after cement, sand and water are mixed, ready to use. An 80 lb bag of mortar mix makes roughly 0.6 to 0.7 ft³ (follow the bag). Mixed mortar weighs about 125 lb per ft³. |
| pallet | A unit for buying bricks in bulk, often about 500 (called a cube). Buying by the pallet from a masonry supplier can lower the price per brick. Enter the bricks per pallet to get the pallets needed, rounded up. |
| rounding up | Changing a number with a decimal part to the next whole number. Bricks are sold one at a time, so bricks, courses, pallets and bags are always rounded up. |
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.
| Area of rectangles and circles (Grades 3–7) |
|
| Converting units of length and area (Grades 4–6) |
|
| Multiplying and dividing decimals (Grade 5) |
|
| Percents (Grade 6) |
|
| Rounding (Grades 3–4) |
|
| Volume of a box (Grade 5) |
|
How to calculate it in Excel
| Long side of the face p (in) | 7.625 |
| Short side of the face q (in) | 3.625 |
| Joint width g (in) | 0.375 |
| Area per brick a (in²) | =(B1+B3)*(B2+B3) |
| Paving area S (ft²) | 60 |
| Waste factor r (%) | 5 |
| Area per brick with joint a (in²) | 32 |
| Net bricks (before rounding up) | =B1*144/B3 |
| Bricks needed with waste N | =ROUNDUP(B1*144*(1+B2/100)/B3,0) |
| Wall length L (ft) | 10 |
| Wall height H (in) | 12 |
| Brick length l (in) | 7.625 |
| Brick height h (in) | 2.25 |
| Joint width g (in) | 0.375 |
| Bricks per course n | =ROUNDUP(B1*12/(B3+B5),0) |
| Courses C | =ROUNDUP(B2/(B4+B5),0) |
| Bricks per course n | 15 |
| Courses C | 5 |
| Waste factor r (%) | 5 |
| Net bricks | =B1*B2 |
| Bricks needed with waste N | =ROUNDUP(B1*B2*(1+B3/100),0) |
| Net bricks N0 | 270 |
| Area per brick with joint a (in²) | 32 |
| Face area of one brick pq (in²) | 27.640625 |
| Joint depth t (in) | 2.25 |
| Joint mortar V (ft³) | =B1*(B2-B3)*B4/1728 |
| Unit price ($) | 0.75 |
| Quantity (bricks or pallets) | 284 |
| Estimated cost ($) | =B1*B2 |
"ROUNDUP(value, 0)" rounds up to a whole number (the ⌈ ⌉ in the formulas).
Square feet are turned into square inches with "*144", feet into inches with "*12", and cubic inches into cubic feet with "/1728". B4 in the first table shows 32.
In the second table, B4 is 270 and B5 is 284 bricks. In the third, B6 is 15 bricks and B7 is 5 courses. In the fourth, B4 is 75 and B5 is 79 bricks. In the fifth, B5 is about 1.53 ft³. In the sixth, B3 is $213. Just change column B to your own numbers.
How to calculate it in Google Sheets
| Long side of the face p (in) | 7.625 |
| Short side of the face q (in) | 3.625 |
| Joint width g (in) | 0.375 |
| Area per brick a (in²) | =(B1+B3)*(B2+B3) |
| Paving area S (ft²) | 60 |
| Waste factor r (%) | 5 |
| Area per brick with joint a (in²) | 32 |
| Net bricks (before rounding up) | =B1*144/B3 |
| Bricks needed with waste N | =ROUNDUP(B1*144*(1+B2/100)/B3,0) |
| Wall length L (ft) | 10 |
| Wall height H (in) | 12 |
| Brick length l (in) | 7.625 |
| Brick height h (in) | 2.25 |
| Joint width g (in) | 0.375 |
| Bricks per course n | =ROUNDUP(B1*12/(B3+B5),0) |
| Courses C | =ROUNDUP(B2/(B4+B5),0) |
| Bricks per course n | 15 |
| Courses C | 5 |
| Waste factor r (%) | 5 |
| Net bricks | =B1*B2 |
| Bricks needed with waste N | =ROUNDUP(B1*B2*(1+B3/100),0) |
| Net bricks N0 | 270 |
| Area per brick with joint a (in²) | 32 |
| Face area of one brick pq (in²) | 27.640625 |
| Joint depth t (in) | 2.25 |
| Joint mortar V (ft³) | =B1*(B2-B3)*B4/1728 |
| Unit price ($) | 0.75 |
| Quantity (bricks or pallets) | 284 |
| Estimated cost ($) | =B1*B2 |
How to calculate it in Python
import math
# ===== Brick and joint (in) =====
brick_length_in = 7.625 # brick length (7-5/8)
brick_width_in = 3.625 # brick width (3-5/8)
brick_height_in = 2.25 # brick height, thickness (2-1/4)
gap_in = 0.375 # joint width (0 for sand joints)
loss_rate = 0.05 # waste factor (5% -> 0.05)
# ===== Paving: laid flat (length x width face up) =====
area_ft2 = 10 * 6 # paving area (10 ft x 6 ft)
face_p = brick_length_in # long side of the face (in)
face_q = brick_width_in # short side of the face (in)
joint_depth = brick_height_in # joint depth = brick height when laid flat (in)
brick_area = (face_p + gap_in) * (face_q + gap_in) # area per brick with joint (in2)
net_count = area_ft2 * 144 / brick_area # net bricks (before rounding up)
bricks_needed = math.ceil(area_ft2 * 144 * (1 + loss_rate) / brick_area) # bricks needed with waste
mortar_ft3 = net_count * (brick_area - face_p * face_q) * joint_depth / 1728 # joint mortar (ft3)
print(f"[Paving] Area per brick: {brick_area:.4f} in2")
print(f"[Paving] Net bricks: {net_count:.2f} -> rounded up {math.ceil(net_count)}")
print(f"[Paving] Bricks needed with waste: {bricks_needed}")
print(f"[Paving] Joint mortar: {mortar_ft3:.2f} ft3")
# ===== Wall: 10 ft long, 12 in high =====
wall_length_in = 10 * 12
wall_height_in = 12
per_course = math.ceil(wall_length_in / (brick_length_in + gap_in)) # bricks per course
courses = math.ceil(wall_height_in / (brick_height_in + gap_in)) # courses
stack_net = per_course * courses # net bricks
stack_needed = math.ceil(stack_net * (1 + loss_rate)) # bricks needed with waste
print(f"[Wall] {per_course} per course x {courses} courses = {stack_net} net bricks")
print(f"[Wall] Bricks needed with waste: {stack_needed}")
How to write it in LaTeX and other math languages (copy and paste)
a = (p + g) × (q + g)
a = (p + g)(q + g)
<math xmlns="http://www.w3.org/1998/Math/MathML" display="block">
<mrow>
<mi>a</mi>
<mo>=</mo>
<mrow><mo>(</mo><mi>p</mi><mo>+</mo><mi>g</mi><mo>)</mo></mrow>
<mo>⁢</mo>
<mrow><mo>(</mo><mi>q</mi><mo>+</mo><mi>g</mi><mo>)</mo></mrow>
</mrow>
</math>
a = (p + g)(q + g)
(p + g)*(q + g)
a := (p + g)*(q + g);
a = (p + g)*(q + g);
a = (p + g)(q + g)
N = ⌈S × (1 + r) ÷ a⌉
N = \left\lceil \frac{S (1 + r)}{a} \right\rceil
<math xmlns="http://www.w3.org/1998/Math/MathML" display="block">
<mrow>
<mi>N</mi>
<mo>=</mo>
<mo>⌈</mo>
<mfrac>
<mrow><mi>S</mi><mo>⁢</mo><mo>(</mo><mn>1</mn><mo>+</mo><mi>r</mi><mo>)</mo></mrow>
<mi>a</mi>
</mfrac>
<mo>⌉</mo>
</mrow>
</math>
N = |~ (S (1 + r)) / a ~|
Ceiling[s (1 + r)/a]
N := ceil(S*(1 + r)/a);
N = ceil(S*(1 + r)/a);
N = ⌈S(1 + r)/a⌉
n = ⌈L ÷ (l + g)⌉, C = ⌈H ÷ (h + g)⌉
n = \left\lceil \frac{L}{l + g} \right\rceil,\quad C = \left\lceil \frac{H}{h + g} \right\rceil
<math xmlns="http://www.w3.org/1998/Math/MathML" display="block">
<mrow>
<mi>n</mi>
<mo>=</mo>
<mo>⌈</mo>
<mfrac><mi>L</mi><mrow><mi>l</mi><mo>+</mo><mi>g</mi></mrow></mfrac>
<mo>⌉</mo>
<mo>,</mo>
<mi>C</mi>
<mo>=</mo>
<mo>⌈</mo>
<mfrac><mi>H</mi><mrow><mi>h</mi><mo>+</mo><mi>g</mi></mrow></mfrac>
<mo>⌉</mo>
</mrow>
</math>
n = |~ L / (l + g) ~|, C = |~ H / (h + g) ~|
{Ceiling[L/(l + g)], Ceiling[H/(h + g)]}
n := ceil(L/(l + g)); C := ceil(H/(h + g));
n = ceil(L/(l + g)); C = ceil(H/(h + g));
n = ⌈L/(l + g)⌉, C = ⌈H/(h + g)⌉
N = ⌈n × C × (1 + r)⌉
N = \lceil n C (1 + r) \rceil
<math xmlns="http://www.w3.org/1998/Math/MathML" display="block">
<mrow>
<mi>N</mi>
<mo>=</mo>
<mo>⌈</mo>
<mi>n</mi><mo>⁢</mo><mi>C</mi><mo>⁢</mo>
<mo>(</mo><mn>1</mn><mo>+</mo><mi>r</mi><mo>)</mo>
<mo>⌉</mo>
</mrow>
</math>
N = |~ n C (1 + r) ~|
Ceiling[n c (1 + r)]
N := ceil(n*C*(1 + r));
N = ceil(n*C*(1 + r));
N = ⌈nC(1 + r)⌉
V = N₀ × (a − p q) × t
V = N_{0} (a - p q) t
<math xmlns="http://www.w3.org/1998/Math/MathML" display="block">
<mrow>
<mi>V</mi>
<mo>=</mo>
<msub><mi>N</mi><mn>0</mn></msub>
<mo>⁢</mo>
<mrow><mo>(</mo><mi>a</mi><mo>-</mo><mi>p</mi><mo>⁢</mo><mi>q</mi><mo>)</mo></mrow>
<mo>⁢</mo>
<mi>t</mi>
</mrow>
</math>
V = N_0 (a - p q) t
n0 (a - p q) t
V := N0*(a - p*q)*t;
V = N0*(a - p*q)*t;
V = N_0 (a − pq) t
T = u × Q
T = u \times Q
<math xmlns="http://www.w3.org/1998/Math/MathML" display="block">
<mrow>
<mi>T</mi>
<mo>=</mo>
<mi>u</mi>
<mo>×</mo>
<mi>Q</mi>
</mrow>
</math>
T = u * Q
u*q
T := u*Q;
T = u*Q;
T = u × Q
How to have ChatGPT do the calculation
You are a quantity calculation assistant for brick work. 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). I am using modular bricks (7-5/8 in × 3-5/8 in × 2-1/4 in). The joint width is 3/8 in and the waste factor is 5%. 1. For a 10 ft × 6 ft patio with the bricks laid flat (7-5/8 × 3-5/8 in face up), find the area per brick with joint (in²), the net bricks (area ÷ area per brick, with 1 ft² = 144 in²), and the bricks needed with waste (net × 1.05, rounded up). 2. For a garden bed edge 10 ft long and 12 in high, find the bricks per course (length ÷ (7-5/8 + 3/8) in, rounded up), the courses (height ÷ (2-1/4 + 3/8) in, rounded up), and the bricks needed with waste. 3. For item 1, find the joint mortar (net bricks × (area per brick − 7.625 × 3.625) × 2.25 in) in cubic feet (1 ft³ = 1,728 in³). Show the formulas you used and the numbers from the execution result.
How to Use
-
1Enter your numbersType the numbers you want to calculate with into the input fields
-
2CalculatePress the "Calculate" button
-
3Check the resultThe result appears on the spot. The same page also explains the idea behind the calculation and the formula
DataChef Features
No technical knowledge required.
Intuitive and user-friendly operation.
Can be used without registering personal information.
Automatic file deletion by clicking "download".
and rapid file conversion.
No attribution required.
No need to contact us for commercial use permission.
