Add ISO 8601 Duration to Date/Time

Add standard ISO 8601 duration strings (e.g. P1Y2M10DT2H30M) to any base date-time with calendar arithmetic.

How It Works & Processing Standards

Add standard ISO 8601 duration strings (e.g. P1Y2M10DT2H30M) to any base date-time with calendar arithmetic.

Your input data is never sent to any server and is securely processed on your device.

Current Limits

  • Maximum input length: 100,000 characters

Add ISO 8601 Duration to Date/Time is a 100% free, browser-based online utility. All calculations and file conversions run locally inside your browser (Local-First) without sending data to remote servers, keeping your documents and inputs strictly private.

How to Use Add ISO 8601 Duration to Date/Time

  1. 1
    Enter Date/TimeInput base date-time (e.g. 2026-05-15T12:00:00).
  2. 2
    Enter DurationType duration string (e.g. P1D, P1Y2M, PT4H).
  3. 3
    Copy ResultInspect resulting date-time.

Common Use Cases

  • Parsing XML/JSON feeds with ISO 8601 duration tokens and calendar event scheduling
Have feedback or ideas for this tool? Suggest & Inquire →