About ISO week numbers
October 23, 2026 is in ISO week 43 of 2026. Some years, including 2026, have 53 ISO weeks. Around New Year, a date can belong to the previous or next year's week numbering (for example, January 1, 2021 was in week 53 of 2020).
Related tools
- Days until any dateCountdown in days and weeks
- Date differenceDays between two dates
- Add or subtract daysFind a date N days away
- Age calculatorExact age in years, months, days
Frequently asked questions
Why does January 1 sometimes show week 53?
Under ISO 8601, week 1 is the week with the year's first Thursday, so early January days can belong to the last week of the previous year.