2025 has 52 ISO 8601 weeks. Week 1 starts on 2024-12-30 (Monday).
| Week | Start (Mon) | End (Sun) | Day-of-year range |
|---|---|---|---|
| 1 | 2024-12-30 | 2025-01-05 | cross-year |
| 2 | 2025-01-06 | 2025-01-12 | 6–12 |
| 3 | 2025-01-13 | 2025-01-19 | 13–19 |
| 4 | 2025-01-20 | 2025-01-26 | 20–26 |
| 5 | 2025-01-27 | 2025-02-02 | 27–33 |
| 6 | 2025-02-03 | 2025-02-09 | 34–40 |
| 7 | 2025-02-10 | 2025-02-16 | 41–47 |
| 8 | 2025-02-17 | 2025-02-23 | 48–54 |
| 9 | 2025-02-24 | 2025-03-02 | 55–61 |
| 10 | 2025-03-03 | 2025-03-09 | 62–68 |
| 11 | 2025-03-10 | 2025-03-16 | 69–75 |
| 12 | 2025-03-17 | 2025-03-23 | 76–82 |
| 13 | 2025-03-24 | 2025-03-30 | 83–89 |
| 14 | 2025-03-31 | 2025-04-06 | 90–96 |
| 15 | 2025-04-07 | 2025-04-13 | 97–103 |
| 16 | 2025-04-14 | 2025-04-20 | 104–110 |
| 17 | 2025-04-21 | 2025-04-27 | 111–117 |
| 18 | 2025-04-28 | 2025-05-04 | 118–124 |
| 19 | 2025-05-05 | 2025-05-11 | 125–131 |
| 20 | 2025-05-12 | 2025-05-18 | 132–138 |
| 21 | 2025-05-19 | 2025-05-25 | 139–145 |
| 22 | 2025-05-26 | 2025-06-01 | 146–152 |
| 23 | 2025-06-02 | 2025-06-08 | 153–159 |
| 24 | 2025-06-09 | 2025-06-15 | 160–166 |
| 25 | 2025-06-16 | 2025-06-22 | 167–173 |
| 26 | 2025-06-23 | 2025-06-29 | 174–180 |
| 27 | 2025-06-30 | 2025-07-06 | 181–187 |
| 28 | 2025-07-07 | 2025-07-13 | 188–194 |
| 29 | 2025-07-14 | 2025-07-20 | 195–201 |
| 30 | 2025-07-21 | 2025-07-27 | 202–208 |
| 31 | 2025-07-28 | 2025-08-03 | 209–215 |
| 32 | 2025-08-04 | 2025-08-10 | 216–222 |
| 33 | 2025-08-11 | 2025-08-17 | 223–229 |
| 34 | 2025-08-18 | 2025-08-24 | 230–236 |
| 35 | 2025-08-25 | 2025-08-31 | 237–243 |
| 36 | 2025-09-01 | 2025-09-07 | 244–250 |
| 37 | 2025-09-08 | 2025-09-14 | 251–257 |
| 38 | 2025-09-15 | 2025-09-21 | 258–264 |
| 39 | 2025-09-22 | 2025-09-28 | 265–271 |
| 40 | 2025-09-29 | 2025-10-05 | 272–278 |
| 41 | 2025-10-06 | 2025-10-12 | 279–285 |
| 42 | 2025-10-13 | 2025-10-19 | 286–292 |
| 43 | 2025-10-20 | 2025-10-26 | 293–299 |
| 44 | 2025-10-27 | 2025-11-02 | 300–306 |
| 45 | 2025-11-03 | 2025-11-09 | 307–313 |
| 46 | 2025-11-10 | 2025-11-16 | 314–320 |
| 47 | 2025-11-17 | 2025-11-23 | 321–327 |
| 48 | 2025-11-24 | 2025-11-30 | 328–334 |
| 49 | 2025-12-01 | 2025-12-07 | 335–341 |
| 50 | 2025-12-08 | 2025-12-14 | 342–348 |
| 51 | 2025-12-15 | 2025-12-21 | 349–355 |
| 52 | 2025-12-22 | 2025-12-28 | 356–362 |
2025 ISO Week Numbers
This page lists every ISO 8601 week of 2025, with the start (Monday) and end (Sunday) date of each week.
Pair it with "Day of Year" and the "Year Calendar" for scheduling and reconciliation.
Features
- All weeks of the year — 52 weeks in total, each with its start and end date.
- Cross-year markers — Weeks that spill into an adjacent year are marked "cross-year" to avoid misreading.
How to use
- Browse the table to see the date range of any ISO week in 2025.
FAQ
Why does an ISO year sometimes have 53 weeks?
2025 has 52 ISO weeks; when most days of the week containing Jan 1 fall in the next year, that year gets 53 weeks.