Convert tools

Add / Subtract from Date

Add signed years, months, days, hours, minutes or seconds to an ISO instant.

Convert in your browser · No sign-up

Calendar operations use UTC. Month and year additions clamp to the last day of the destination month. Negative amounts subtract.

Up to 100,000 UTF-16 units per input and 1,000,000 per result. See the supported formats and examples below.

How to use

  1. Add signed years, months, days, hours, minutes or seconds to an ISO instant.
  2. Choose the mode or options, then run the tool.
  3. Review the result, then copy or download the TXT file.

Example

2024-01-31 + 1 month → 2024-02-29

Details and limitations

Calendar operations use UTC. Month and year additions clamp to the last day of the destination month. Negative amounts subtract.

Text stays in your browser; it is not sent to a conversion server.

FAQ

Add / Subtract from Date — What are the supported inputs and limits?

Calendar operations use UTC. Month and year additions clamp to the last day of the destination month. Negative amounts subtract.

Format references

Tool page updated: