How to calculate time in Excel - time difference, adding / subtracting times

Formula 1. Subtract one time from the other

As you probably know, times in Excel are usual decimal numbers formatted to look like times. And because they are numbers, you can add and subtract times just as any other numerical values.

The simplest and most obvious Excel formula to calculate time difference is this:

Depending on you data structure, the actual time difference formula may take various shapes, for example:

Remembering that in the internal Excel system, times are represented by fractional parts of decimal numbers, you are likely to get the results similar to this:

The decimals in column D are perfectly true but not very meaningful. To make them more informative, you can apply custom time formatting with one of the following codes:

To apply the custom time format, click Ctrl + 1 to open the Format Cells dialog, select Custom from the Category list and type the time codes in the Type box. Please see Creating a custom time format in Excel for the detailed steps.

And now, let's see how our time difference formula and time codes work in real worksheets. With Start times residing in column A and End times in column B, you can copy the following formula in columns C though E:

=$B2-$A2

The elapsed time is displayed differently depending on the time format applied to the column:

Formula 2. Calculating time difference with the TEXT function

Another simple technique to calculate the duration between two times in Excel is using the TEXT function:

• Calculate hours between two times:

  =TEXT(B2-A2, "h")

• Return hours and minutes between 2 times:

  =TEXT(B2-A2, "h:mm")

• Return hours, minutes and seconds between 2 times:

  =TEXT(B2-A2, "h:mm:ss")

Formula 3. Count hours, minutes or seconds between two times

To get the time difference in a single time unit (hours ,minutes or seconds), you can perform the following calculations.

Calculate hours between two times:

To present the difference between two times as a decimal number, use this formula:

Supposing that your start time is in A2 and end time in B2, you can use a simple equation B2-A2 to calculate the difference between two times, and then multiply it by 24, which is the number of hours in one day:

=(B2-A2) * 24

To get the number of complete hours, use the INT function to round the result down to the nearest integer:

=INT((B2-A2) * 24)

Total minutes between two times:

To calculate the minutes between two times, multiply the time difference by 1440, which is the number of minutes in one day (24 hours * 60 minutes = 1440).

As demonstrated in the following screenshot, the formula can return both positive and negative values, the latter occur when the end time is less than the start time, like in row 5:

=(B2-A2)*1440

Total seconds between times:

To get the total seconds between two times, you multiply the time difference by 86400, which is the number of seconds in one day (24 hours * 60 minutes * 60 seconds = 86400).

In our example, the formula is as follows:

=(B2-A2)* 86400

Formula 4. Calculate difference in one time unit ignoring others

To find the difference between 2 times in a certain time unit, ignoring the others, use one of the following functions.

• Difference in hours, ignoring minutes and seconds:

  =HOUR(B2-A2)

• Difference in minutes, ignoring hours and seconds:

  =MINUTE(B2-A2)

• Difference in seconds, ignoring hours and minutes:

  =SECOND(B2-A2)

When using Excel's HOUR, MINUTE and SECOND functions, please remember that the result cannot exceed 24 for hours and 60 for minutes and seconds.

Formula 5. Calculate elapsed time from a start time to now

In order to calculate how much time has elapsed since the start time to now, you simply use the NOW function to return today's date and the current time, and then subtract the start date and time from it.

Supposing that the beginning date and time is in call A2, the formula below returns the following results, provided you've applied an appropriate time format to column B, h:mm in this example:

=NOW()-A2

In case the elapsed time exceeds 24 hours, use one of these time formats, for example d "days" h:mm:ss like in the following screenshot:

If your starting points contain only time values without dates, you need to use the TIME function to calculate the elapsed time correctly. For example, the following formula returns the time elapsed since the time value in cell A2 up to now:

=TIME(HOUR(NOW()), MINUTE(NOW()), SECOND(NOW())) - A2

Formula 5. Display time difference as "XX days, XX hours, XX minutes and XX seconds"

This is probably the most user-friendly formula to calculate time difference in Excel. You use the HOUR, MINUTE and SECOND functions to return corresponding time units and the INT function to compute the difference in days. And then, you concatenate all these functions in a single formula along with the text labels:

=INT(B2-A2) & " days, " & HOUR(B2-A2) & " hours, " & MINUTE(B2-A2) & " minutes and " & SECOND(B2-A2) & " seconds"

To instruct your Excel time difference formula to hide zero values, embed four IF functions into it:

=IF(INT(B2-A2)>0, INT(B2-A2) & " days, ","") & IF(HOUR(B2-A2)>0, HOUR(B2-A2) & " hours, ","") & IF(MINUTE(B2-A2)>0, MINUTE(B2-A2) & " minutes and ","") & IF(SECOND(B2-A2)>0, SECOND(B2-A2) & " seconds","")

The syntax may seem excessively complicated, but it works :)

Alternatively, you can calculate time difference by simply subtracting the start time from the end time (e.g. =B2-A2), and then apply the following time format to the cell:

d "days," h "hours," m "minutes and" s "seconds"

An advantage of this approach is that your result would be a normal time value that you could use in other time calculations, while the result of the complex formula discussed above is a text value. A drawback is that the custom time format cannot distinguish between zero and non-zero values and ignore the latter. To display the result in other formats, please see How to show time over 24 hours, 60 minutes, 60 seconds.

Method 1. Change Excel Date System to 1904 date system

The fastest and easiest way to display negative time normally (with a minus sign) is switching to the 1904 date system. To do this, click File > Options > Advanced, scroll down to the When calculating this workbook section and put a tick in the Use 1904 date system box.

Click OK to save the new settings, and from now on negative times will be displayed correctly, like negative numbers:

Method 2. Calculate negative time in Excel with formulas

Is changing Excel's default Date System is not an option, then you can force negative times to display properly using one of the following formulas:

=IF(A2-B2>0, A2-B2, "-" & TEXT(ABS(A2-B2),"h:mm"))

=IF(A2-B2>0, A2-B2, TEXT(ABS(A2-B2),"-h:mm"))

Both formulas check if the time difference (A2-B2) is greater than 0, and if it is they return that difference. If the time difference is less than zero, the first formula calculates the absolute difference and concatenates the minus sign. The second formula yields exactly the same result by using a negative time format "-h::mm".

How to add or subtract hours to time in Excel

To add hours to a given time in Excel, you can use one the following formulas.

TIME function to add under 24 hours

For example, if your start time is in cell A2, and you want to add 2 hours to it, the formula is as follows:

=A2 + TIME(2, 0, 0)

Formula to add any number of hours (under or over 24 hours)

The following formula has no limitations to the number of hours you want to add:

For example, to add 28 hours to the start time in cell A2, enter the following formula:

=A2 + (28/24)

To subtract hours from a given time, you use analogous formulas, and just replace "+" with the minus sign:

For example, to subtract 3 hours from the time in cell A2, either of the following formulas will do:

=A2-(3/24)

=A2-TIME(3,0,0)

To subtract more than 23 hours, use the first one.

How to add / subtract minutes to time in Excel

To add minutes to a given time, employ the same techniques that we've just used for adding hours.

To add or subtract under 60 minutes

Use the TIME function and supply the minutes you want to add or subtract in the second argument:

And here are a couple of real-life formulas to calculate minutes in Excel:

To add 20 minutes to the time in A2: =A2 + TIME(0,20,0)

To subtract 30 minutes from the time in A2: =A2 - TIME(0,30,0)

To add or subtract over 60 minutes

In your calculation, divide the number of minutes by 1440, which is the number of minutes in a day, and add the quotient to the start time:

To subtract minutes from time, simply replace plus with the minus sign. For example:

To add 200 minutes: =A2 + (200/1440)

To subtract 300 minutes: =A2 -(300/1440)

How to add / subtract seconds to a given time

Second calculations in Excel are done in a similar fashion.

To add under 60 seconds to a given time, you can use the TIME function:

To add more than 59 seconds, use the following formula:

To subtract seconds, utilize the same formulas with the minus sign (-) instead of plus (+).

In your Excel worksheets, the formulas may look similar to these:

To add 30 seconds to A2: =A2 + TIME(0,0,31)

To add 1200 seconds to A2: =A2 + (1200/86400)

To subtract 40 seconds from A2: =A2 - TIME(0,0,40)

To subtract 900 seconds from A2: =A2 - (900/86400)

How to sum over 24 hours in Excel

In order to add up more than 24 hours, you use the same SUM formula as discussed above, and apply one of the following time formats to the cell:

To see how these custom time formats may look like in your Excel worksheet, please have a look at the screenshot below, where the same SUM formula is entered in cells A9 to A13:

=SUM($B$2:$B$4)

Also, please keep in mind that the time format applied to a cell changes only the display presentation without changing the cell's value. For example, in the screenshot above, cell A13 looks like text, but in fact it's a usual time value, which is stored as a decimal in the internal Excel system. Meaning, you are free to refer to that cell in other formulas and calculations.

For more information, please see How to calculate and show over 24 hours, 60 minutes, 60 seconds.