Add seconds to a time

You can add (or subtract) a number of seconds from a time using fractions.
Dates are represented as sequential whole numbers so 1 hour is equivalent to the fraction (1/24).
Times are represented as fractions based on there being 24 hours in a day.
1 Hour is 1/24 = 0.04166
1 Minute is 1/(24*60) = 1/1440
1 Second is 1/(24*60*60) = 1/86400

Example

	A
1	=TODAY() = Friday 01 December 2023
2	=NOW() = Friday 01 December 2023 08:57:05
3	=A2+(200*(1/86400)) = Friday, 01 December, 2023 09:00 AM
4	=A2+TIME(0,0,200) = Friday, 01 December, 2023 09:00 AM
5	=A2+(40/1440)+(50/86400) = Friday, 01 December, 2023 09:37 AM
6	=A2+TIME(0,40,50) = Friday, 01 December, 2023 09:37 AM
7	=A2+(3/24)+(15/1440)+(30/86400) = Friday, 01 December, 2023 12:12 PM
8	=A2+TIME(3,15,30) = Friday, 01 December, 2023 12:12 PM

1 - Displays the current date. Custom format "dddd dd mmmm yyyy".
2 - Displays the current date and time. Custom format "dddd dd mmmm yyyy hh:mm:ss".
3 - Displays the current time plus 200 seconds.
4 - Displays the current time plus 200 seconds using the TIME function to return the correct decimal.
5 - Displays the current time plus 40 minutes and 50 seconds.
6 - Displays the current time plus 40 minutes and 50 seconds using the TIME function to return the correct decimal.
7 - Displays the current time plus 3 hours, 15 minutes and 30 seconds.
8 - Displays the current time plus 3 hours, 15 minutes and 30 seconds using the TIME function to return the correct decimal.
All these cells have been formatted with the custom number format "dddd, dd mmmm, yyyy hh:mm AM/PM".

Built-in Functions

NOW - The date serial number of the current system date and time.
TIME - The time as a decimal given an hour, minute, second.
TODAY - The date serial number representing today's date.

Related Formulas

Add hours to a time
Add minutes to a time
Subtract seconds from a time