Date & Time

Add Time to a Date

Add or subtract years, months, weeks, days, hours, minutes, and seconds — in any combination — to a date. Use negative numbers to subtract.

Date or date-time

Settings

Output

Result appears here after you select

{ } How to use

  1. Enter a date (e.g. 2024-01-15) or a date-time (e.g. 2024-01-15 09:30:00).
  2. Fill in any units to add — leave the rest at 0; use negatives to subtract.
  3. The result updates as you change the options; copy or download it.

{ } How it works

Add Time to a Date works on the text you provide. Adjust the options, then select Process ▸ and it runs entirely in your browser — nothing is uploaded to a server — then shows the result in the Output panel.

Inputs

  • Date or date-time — paste or type your input in the left panel (use Sample for an example)
  • Years — a value (default: "0")
  • Months — a value (default: "0")
  • Weeks — a value (default: "0")
  • Days — a value (default: "10")
  • Hours — a value (default: "0")
  • Minutes — a value (default: "0")
  • Seconds — a value (default: "0")

Output

TXT text — copy or download it from the Output panel.

{ } Common uses

  • Work out a deadline thirty days from a start date.
  • Find the date a subscription renews after a year.
  • Step a date backwards by entering a negative number.

{ } Limitations

  • All arithmetic is done in UTC, and a date typed without a timezone is read as UTC. That is deliberate: it makes the same input give the same answer everywhere instead of shifting by each reader’s own offset.
  • Months are added before days, and a month-end date can roll over: 31 January plus one month lands on 2 or 3 March, because there is no 31 February. This is how most date libraries behave, and it is worth checking whenever the day is near the end of a month.
  • A time appears in the result only if you added hours, minutes or seconds, or your input already contained one.

{ } FAQ

Is my data uploaded to a server?

No. Everything runs locally in your browser — your files never leave your device.

Can I process more than one file at once?

This tool works on one input at a time.

Is this tool free?

Yes — it’s completely free and needs no sign-up.

Why did 31 January plus one month give me March?

Because adding a month to the 31st asks for 31 February, which does not exist, so the overflow rolls into March. If you want “the end of next month”, add one month to the 1st and then subtract a day.