Tools

ISO Week Converter Between Weeks and Dates

Convert ISO week numbers to calendar dates and back.

ISO Week Converter

Convert between ISO week numbers and calendar dates for reporting and planning. This is useful when teams track sprints or metrics by ISO week.

How to use the ISO Week Converter

  1. Enter an ISO week or a calendar date.
  2. Click Convert.
  3. Review the week number or date range.

Common use cases

  • Translating ISO weeks in reports.
  • Planning sprints or releases.
  • Aligning dates across ISO-based systems.
  • Converting week-based schedules.

Tips & notes

  • ISO weeks start on Monday.
  • Week 1 is the week with the year’s first Thursday.
  • Use Week Number Calculator for single-date lookups.

Related time tools

  • Week Number Calculator
  • Month Calendar Generator
  • Date Range Splitter

FAQ

Which standard?
ISO 8601 week numbering.
Do ISO weeks start on Monday?
Yes. Monday is the first day of the ISO week.
Can week numbers belong to another year?
Yes. ISO week years can differ near year boundaries.