Time Calculator (Add and Subtract Days, Hours, Minutes and Seconds)

Enter time 1 and time 2 in days, hours, minutes and seconds. You get both the sum (time 1 + time 2) and the difference (time 1 − time 2) at once.

Time 1: days

Time 1: hours

Time 1: minutes

Time 1: seconds

Time 2: days

Time 2: hours

Time 2: minutes

Time 2: seconds

Fields you do not need can be left blank (or 0). Large numbers such as 90 minutes or 36 hours can be entered as they are. When the difference is negative, it is shown with a minus sign in front.

Result

Enter two times (days, hours, minutes, seconds) in the fields on the left and press "Calculate". The result will appear here.

[ CLOSE ]

What you can do on this page
What is this calculation used for?
How to Use
Formula
Symbols and terms
- Symbols
- 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

Add or subtract two lengths of time given in days, hours, minutes and seconds, such as "1 day 2 hours 30 minutes + 23 hours 45 minutes 10 seconds"
The sum (time 1 + time 2) and the difference (time 1 − time 2) are calculated and shown together
Carrying and borrowing at 60 seconds = 1 minute, 60 minutes = 1 hour and 24 hours = 1 day are done for you, and the steps in seconds are shown too
When a subtraction comes out negative, the result is shown clearly, as in "−1 day 2 hours"
A plain-language explanation of the formulas and copy-and-paste formulas for Excel, Google Sheets and Python are all on this page

This page adds and subtracts lengths of time, such as "2 hours 30 minutes". To add time to a date and time on the calendar, as in "What is 36 hours after 8:30 AM on July 12?", use the date and time calculator among the related pages.

What is this calculation used for?

Adding up hours worked and overtime (time card totals)

If you work 8 hours 45 minutes on Monday and 7 hours 50 minutes on Tuesday, the total for the two days is 16 hours 35 minutes (minutes: 45 + 50 = 95, which carries to 1 hour 35 minutes; hours: 8 + 7 + 1 = 16).
Payroll and time tracking add up each day's hours like this, and in the US, hours over 40 in a week are usually paid as overtime. Adding and subtracting time goes straight into everyone's paycheck.

Finding the difference between race times (sports)

If your marathon time this year is 3:28:50 and last year's was 3:45:30, you improved by 16 minutes 40 seconds (3:45:30 − 3:28:50 = 0:16:40).
In timed sports such as running, swimming and cycling, athletes calculate the gap to their personal best, or to a rival, down to the second to check their progress and pacing.

Estimating the total length of videos and audio (editing, playlists)

Watching a 1 hour 48 minute movie and a 2 hour 15 minute movie back to back takes 4 hours 3 minutes in total (minutes: 48 + 15 = 63, which carries over).
Adding up the lengths of clips in video editing, or estimating how long a playlist or a set of meeting recordings runs, is exactly this kind of time addition.

Adding up the time for cooking and tasks (planning)

A dish with 30 minutes of prep and 1 hour 45 minutes of simmering takes 2 hours 15 minutes in total from the start.
Adding up the time for each step tells you how long the whole thing takes, and subtracting it from mealtime tells you when to start. The same calculation helps you plan the steps of any job.

Finding how much sleep you are missing (health)

If your sleep goal is 7 hours and you actually slept 5 hours 30 minutes, you are 1 hour 30 minutes short.
Sleep tracking apps find "the gap from your goal" with this same subtraction. Seeing the shortfall as a number makes it easier to decide "I should go to bed early tonight".

Formula

Adding and subtracting times (sum and difference)

Standard notation (the usual math form)

\(S\) \(=\) \(T_1\) \(+\) \(T_2\)

\(D\) \(=\) \(T_1\) \(-\) \(T_2\)

In words (symbols replaced with words)

③ \(S\): sum of the two times \(=\) ① \(T_1\): time 1 \(+\) ② \(T_2\): time 2

\(D\): difference of the two times \(=\) \(T_1\): time 1 \(-\) \(T_2\): time 2

The formula in words

① Take \(T_1\): time 1

② add \(T_2\): time 2

③ and you get the \(S\): sum of the two times (subtract time 2 from time 1 instead, and you get the difference \(D\))

Quick example

For the sum of "1 day 2 hours 30 minutes" and "23 hours 45 minutes 10 seconds", putting each into seconds (formula 2 below) gives 95400 seconds and 85510 seconds, so

sum (2 days 2 hours 15 minutes 10 seconds) \(=\) time 1 (1 day 2 hours 30 minutes) \(+\) time 2 (23 hours 45 minutes 10 seconds)

\(95400 + 85510 = 180910\)

\(180910 = 86400 \times 2 + 3600 \times 2 + 60 \times 15 + 10\)

Key idea

Add and subtract days, hours, minutes and seconds unit by unit, and carry into the next larger unit when you pass 60 seconds, 60 minutes or 24 hours (for example, 30 minutes + 45 minutes = 75 minutes → 1 hour 15 minutes). Working with mixed units makes it easy to slip when carrying or borrowing, so this calculator first puts everything into seconds and does a single addition or subtraction (formulas 2 and 3 below). When a difference is negative, a single minus sign goes in front, as in "−1 day 2 hours", to show how much time is missing.

Putting a time into seconds

Standard notation (the usual math form)

\(T\) \(=\) \(86400\) \(\times\) \(d\) \(+\) \(3600\) \(\times\) \(h\) \(+\) \(60\) \(\times\) \(m\) \(+\) \(s\)

In words (symbols replaced with words)

⑧ \(T\): time in seconds \(=\) ② \(86400\): seconds in a day \(\times\) ① \(d\): days \(+\) ④ \(3600\): seconds in an hour \(\times\) ③ \(h\): hours \(+\) ⑥ \(60\): seconds in a minute \(\times\) ⑤ \(m\): minutes \(+\) ⑦ \(s\): seconds

The formula in words

① Take the \(d\): days

② and multiply by \(86400\): seconds in a day

③ take the \(h\): hours

④ and multiply by \(3600\): seconds in an hour

⑤ take the \(m\): minutes

⑥ and multiply by \(60\): seconds in a minute

⑦ add all of these and the \(s\): seconds

⑧ and you get the \(T\): time in seconds

Quick example

"1 day 2 hours 30 minutes" in seconds is

time in seconds (95400 s) \(=\) seconds in a day (86400) \(\times\) days (1 day) \(+\) seconds in an hour (3600) \(\times\) hours (2 hours) \(+\) seconds in a minute (60) \(\times\) minutes (30 minutes)

\(T = 86400 \times 1 + 3600 \times 2 + 60 \times 30 = 95400\)

Key idea

1 day = 24 hours, 1 hour = 60 minutes and 1 minute = 60 seconds, so a day has \(24 \times 60 \times 60 = 86400\) seconds and an hour has \(60 \times 60 = 3600\) seconds. A time in mixed units, such as "1 day and 2 hours 30 minutes", becomes a single addition or subtraction once everything is in the smallest unit, seconds. The "Step by step" part of this calculator's result shows time 1 and time 2 put into seconds with this formula.

Turning seconds back into days, hours, minutes and seconds (quotient and remainder)

Standard notation (the usual math form)

\(T\) \(=\) \(86400\) \(\times\) \(q\) \(+\) \(r\)

In words (symbols replaced with words)

④ \(T\): time in seconds \(=\) ① \(86400\): seconds in a day \(\times\) ② \(q\): days \(+\) ③ \(r\): seconds left over

The formula in words

① Take \(86400\): seconds in a day

② multiply by the \(q\): days

③ add the \(r\): seconds left over

④ and you get the \(T\): time in seconds (to find them, divide \(T\) by \(86400\). The quotient is the days \(q\) and the remainder is the seconds left over \(r\). Divide \(r\) by \(3600\) and then by \(60\) in the same way to split it into hours, minutes and seconds)

Quick example

To turn the sum in the formula 1 example, 180910 seconds, into days, hours, minutes and seconds, divide by 86400, 3600 and 60 in turn and use the quotients and remainders

time in seconds (180910 s) \(=\) seconds in a day (86400) \(\times\) days (2 days) \(+\) seconds left over (8110 s)

\(180910 = 86400 \times 2 + 8110\)

\(8110 = 3600 \times 2 + 910\)

\(910 = 60 \times 15 + 10\)

Key idea

Just by repeating division with remainders, a large number of seconds turns back into an easy-to-read form such as "2 days 2 hours 15 minutes 10 seconds". When a difference is negative, split the absolute value (the number without its sign) with this formula, then put a single minus sign in front (for example, −93784 seconds → −1 day 2 hours 3 minutes 4 seconds). This calculator leaves out units that are 0, and shows "0 seconds" when the whole result is 0.

The basics of adding and subtracting times: put the days, hours, minutes and seconds into seconds, add or subtract, then divide by 86400, 3600 and 60 in turn to get back to days, hours, minutes and seconds. Working in seconds turns everything into one calculation, with no mistakes in carrying or borrowing.

Symbols and terms

Symbols

\(T_1\), \(T_2\)	T sub 1, T sub 2	The two times (lengths of time) you calculate with: time 1 (\(T_1\)) and time 2 (\(T_2\)). (Example - \(T_1\) = 1 day 2 hours 30 minutes, \(T_2\) = 23 hours 45 minutes 10 seconds)
\(S\)	S	The sum of the two times (time 1 + time 2), from the first letter of "sum".
\(D\)	D (capital)	The difference of the two times (time 1 − time 2), from the first letter of "difference". Do not confuse it with lowercase \(d\) (days).
\(d\), \(h\), \(m\), \(s\)	d, h, m, s	The parts of a time: days (\(d\)), hours (\(h\)), minutes (\(m\)) and seconds (\(s\)). For "1 day 2 hours 30 minutes", \(d = 1\), \(h = 2\), \(m = 30\) and \(s = 0\). They are the first letters of day, hour, minute and second.
\(T\)	T (capital)	A time written in seconds. Found with \(T = 86400d + 3600h + 60m + s\). (Example - 1 day 2 hours 30 minutes → 95400 seconds)
\(q\), \(r\)	q, r	When a time in seconds is divided by 86400, the quotient (the days \(q\)) and the remainder (the seconds left over \(r\)). For \(180910 \div 86400 = 2\) remainder \(8110\), \(q = 2\) and \(r = 8110\).

Terms

time of day	A point in time, such as 8:30. It is different from a length of time, such as 2 hours 30 minutes. For calculations with a time of day ("What time will it be in 5 hours?"), use the date and time calculator among the related pages.
duration	A length of time, such as 2 hours 30 minutes. It is different from a time of day, such as 8:30. This page adds and subtracts durations.
base 60	A way of counting where 60 makes one of the next larger unit (also called sexagesimal). 60 seconds carry to 1 minute, and 60 minutes carry to 1 hour. Note that between hours and days, you carry at 24 instead.
carrying	In addition, moving the part that goes past the limit of a unit into the next larger unit (30 minutes + 45 minutes = 75 minutes → 1 hour 15 minutes). With time, you carry at 60 or 24.
borrowing	In subtraction, taking what you are short from the next larger unit (1 hour 15 minutes − 30 minutes → 75 minutes − 30 minutes = 45 minutes). With time, you borrow 60 or 24.
quotient	The answer to "how many times does it fit?" in a division. For \(180910 \div 86400 = 2\) remainder \(8110\), the quotient is \(2\), which is the number of days.
remainder	What is left over when a division does not come out even. For \(180910 \div 86400 = 2\) remainder \(8110\), the remainder is \(8110\), the seconds left over that do not make a full day.
absolute value	The size of a number without its sign (plus or minus). The absolute value of −93784 seconds is 93784 seconds. To split a negative time into days, hours, minutes and seconds, split the absolute value and then put a minus sign in front.

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.
If you get stuck, going back over these topics is the quickest way forward.

Time of day and elapsed time (Grades 2–3)	Knowing the difference between a time of day (a point in time, such as 8:30) and a duration (a length of time, such as 2 hours 30 minutes) Knowing that 1 day = 24 hours, 1 hour = 60 minutes and 1 minute = 60 seconds
Adding and subtracting with regrouping (Grade 2)	Being able to do 2-digit addition and subtraction such as 30 + 45 = 75 and 60 − 30 = 30 Seeing that "minutes past 60 carry into hours, and hours past 24 carry into days" is the same idea as regrouping
Division with remainders (Grade 4)	Being able to find the quotient and remainder, as in 36 ÷ 24 = 1 remainder 12 Seeing that division with a remainder splits a large number of seconds into days, hours, minutes and seconds
Positive and negative numbers (Grades 6–7)	Knowing that when you subtract a larger number, the answer is negative, as in 60 − 90 = −30 Knowing that a negative answer means "short by that much"

How to calculate it in Excel

Copy the whole table below and paste it into cell A1 in Excel. It works as is.

Table for the sum and difference of two times

Time 1: days	1
Time 1: hours	2
Time 1: minutes	30
Time 1: seconds	0
Time 2: days	0
Time 2: hours	23
Time 2: minutes	45
Time 2: seconds	10
Time 1 in seconds	=B186400+B23600+B3*60+B4
Time 2 in seconds	=B586400+B63600+B7*60+B8
Sum (seconds)	=B9+B10
Difference (seconds)	=B9-B10
Sum: days	=QUOTIENT(B11,86400)
Sum: hours	=QUOTIENT(MOD(B11,86400),3600)
Sum: minutes	=QUOTIENT(MOD(B11,3600),60)
Sum: seconds	=MOD(B11,60)
Difference: days	=QUOTIENT(ABS(B12),86400)
Difference: hours	=QUOTIENT(MOD(ABS(B12),86400),3600)
Difference: minutes	=QUOTIENT(MOD(ABS(B12),3600),60)
Difference: seconds	=MOD(ABS(B12),60)

Table to put a time into seconds

Days	1
Hours	2
Minutes	30
Seconds	0
Time in seconds	=B186400+B23600+B3*60+B4

Table to turn seconds back into days, hours, minutes and seconds

Time in seconds	180910
Days	=QUOTIENT(B1,86400)
Hours	=QUOTIENT(MOD(B1,86400),3600)
Minutes	=QUOTIENT(MOD(B1,3600),60)
Seconds	=MOD(B1,60)

In the first table, enter the days, hours, minutes and seconds of time 1 and time 2 in B1 to B8. B9 and B10 put them into seconds (95400 and 85510 seconds), B11 shows the sum (180910 seconds) and B12 shows the difference (9890 seconds). B13 to B16 split the sum into days, hours, minutes and seconds with QUOTIENT (the quotient of a division) and MOD (the remainder of a division), giving 2 days, 2 hours, 15 minutes and 10 seconds. B17 to B20 split the difference, giving 0 days, 2 hours, 44 minutes and 50 seconds.
The split of the difference uses ABS (absolute value). When B12 is negative, B17 to B20 show the parts without the sign, so look at the sign of B12 and read the result with a minus sign in front.
The second table gives 95400 (seconds), and the third gives 2 days, 2 hours, 15 minutes and 10 seconds. Just replace column B with your own numbers.

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 for the sum and difference of two times

Time 1: days	1
Time 1: hours	2
Time 1: minutes	30
Time 1: seconds	0
Time 2: days	0
Time 2: hours	23
Time 2: minutes	45
Time 2: seconds	10
Time 1 in seconds	=B186400+B23600+B3*60+B4
Time 2 in seconds	=B586400+B63600+B7*60+B8
Sum (seconds)	=B9+B10
Difference (seconds)	=B9-B10
Sum: days	=QUOTIENT(B11,86400)
Sum: hours	=QUOTIENT(MOD(B11,86400),3600)
Sum: minutes	=QUOTIENT(MOD(B11,3600),60)
Sum: seconds	=MOD(B11,60)
Difference: days	=QUOTIENT(ABS(B12),86400)
Difference: hours	=QUOTIENT(MOD(ABS(B12),86400),3600)
Difference: minutes	=QUOTIENT(MOD(ABS(B12),3600),60)
Difference: seconds	=MOD(ABS(B12),60)

Table to put a time into seconds

Days	1
Hours	2
Minutes	30
Seconds	0
Time in seconds	=B186400+B23600+B3*60+B4

Table to turn seconds back into days, hours, minutes and seconds

Time in seconds	180910
Days	=QUOTIENT(B1,86400)
Hours	=QUOTIENT(MOD(B1,86400),3600)
Minutes	=QUOTIENT(MOD(B1,3600),60)
Seconds	=MOD(B1,60)

In Google Sheets, QUOTIENT (the quotient of a division), MOD (the remainder of a division) and ABS (absolute value) work exactly as in Excel. Copy the whole table, paste it into cell A1, and replace column B with your own numbers. The answers are the same as in Excel.

How to calculate it in Python

# Time 1 and time 2 (days, hours, minutes, seconds)
days1, hours1, minutes1, seconds1 = 1, 2, 30, 0
days2, hours2, minutes2, seconds2 = 0, 23, 45, 10

total_seconds1 = days1 * 86400 + hours1 * 3600 + minutes1 * 60 + seconds1
total_seconds2 = days2 * 86400 + hours2 * 3600 + minutes2 * 60 + seconds2
sum_seconds = total_seconds1 + total_seconds2    # sum (seconds)
diff_seconds = total_seconds1 - total_seconds2   # difference (seconds)

def format_duration(total_seconds):
    # Turn seconds back into "2 days 2 hours 15 minutes 10 seconds" (units that are 0 are left out; a single minus sign in front)
    if total_seconds == 0:
        return "0 seconds"
    sign = "−" if total_seconds < 0 else ""
    rest = abs(total_seconds)
    days, rest = divmod(rest, 86400)
    hours, rest = divmod(rest, 3600)
    minutes, seconds = divmod(rest, 60)
    parts = []
    if days: parts.append(f"{days} day{'s' if days != 1 else ''}")
    if hours: parts.append(f"{hours} hour{'s' if hours != 1 else ''}")
    if minutes: parts.append(f"{minutes} minute{'s' if minutes != 1 else ''}")
    if seconds: parts.append(f"{seconds} second{'s' if seconds != 1 else ''}")
    return sign + " ".join(parts)

print(f"Time 1: {total_seconds1} seconds, time 2: {total_seconds2} seconds")
print(f"Sum: {format_duration(sum_seconds)} ({sum_seconds} seconds)")
print(f"Difference: {format_duration(diff_seconds)} ({diff_seconds} seconds)")

Runs with the standard library only. divmod is a function that returns the quotient and the remainder of a division at the same time. Dividing by 86400, 3600 and 60 in turn splits the seconds into days, hours, minutes and seconds. Change the numbers for time 1 and time 2 at the top, then run it.

How to write it in LaTeX and other math languages (copy and paste)

Adding and subtracting times (sum and difference)

S = T₁ + T₂,  D = T₁ − T₂

S = T_1 + T_2, \quad D = T_1 - T_2

<math xmlns="http://www.w3.org/1998/Math/MathML" display="block">
  <mrow>
    <mi>S</mi><mo>=</mo>
    <msub><mi>T</mi><mn>1</mn></msub><mo>+</mo>
    <msub><mi>T</mi><mn>2</mn></msub>
    <mo>,</mo><mspace width="0.7em"/>
    <mi>D</mi><mo>=</mo>
    <msub><mi>T</mi><mn>1</mn></msub><mo>&#x2212;</mo>
    <msub><mi>T</mi><mn>2</mn></msub>
  </mrow>
</math>

S = T_1 + T_2, D = T_1 - T_2

sum = t1 + t2; difference = t1 - t2

S := T1 + T2; difference := T1 - T2;

S = T1 + T2; D = T1 - T2;

S = T_1 + T_2, D = T_1 - T_2

Putting a time into seconds

T = 86400d + 3600h + 60m + s

T = 86400d + 3600h + 60m + s

<math xmlns="http://www.w3.org/1998/Math/MathML" display="block">
  <mrow>
    <mi>T</mi><mo>=</mo>
    <mn>86400</mn><mi>d</mi>
    <mo>+</mo><mn>3600</mn><mi>h</mi>
    <mo>+</mo><mn>60</mn><mi>m</mi>
    <mo>+</mo><mi>s</mi>
  </mrow>
</math>

T = 86400d + 3600h + 60m + s

totalSeconds = 86400*d + 3600*h + 60*m + s

T := 86400*d + 3600*h + 60*m + s;

T = 86400*d + 3600*h + 60*m + s;

T = 86400d + 3600h + 60m + s

Turning seconds back into days, hours, minutes and seconds (quotient and remainder)

T = 86400q + r

T = 86400q + r

<math xmlns="http://www.w3.org/1998/Math/MathML" display="block">
  <mrow>
    <mi>T</mi><mo>=</mo>
    <mn>86400</mn><mi>q</mi>
    <mo>+</mo><mi>r</mi>
  </mrow>
</math>

T = 86400q + r

q = Quotient[t, 86400]; r = Mod[t, 86400]

q := iquo(T, 86400); r := irem(T, 86400);

q = floor(T/86400); r = mod(T, 86400);

T = 86400q + r

How to have ChatGPT do the calculation

You are a time calculation assistant. 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).

For time 1 "1 day 2 hours 30 minutes 0 seconds" and time 2 "0 days 23 hours 45 minutes 10 seconds", find the sum (time 1 + time 2) and the difference (time 1 − time 2).
Put each into seconds before adding and subtracting, then turn the results back into the form "X days Y hours Z minutes W seconds", carrying at 60 seconds = 1 minute, 60 minutes = 1 hour and 24 hours = 1 day. If the difference is negative, split its absolute value and put a minus sign in front.

Show the code you used, the values in seconds along the way, and the final results.

How to Use

1

Enter your numbers

Type the numbers you want to calculate with into the input fields
2

Calculate

Press the "Calculate" button
3

Check the result

The result appears on the spot. The same page also explains the idea behind the calculation and the formula