Weeknummers in het jaar 1981
| Week | Begint (ma) | Eindigt (zo) | Even / oneven |
|---|---|---|---|
| Week 1 | 29 december 1980 | 4 januari 1981 | oneven week |
| Week 2 | 5 januari 1981 | 11 januari 1981 | even week |
| Week 3 | 12 januari 1981 | 18 januari 1981 | oneven week |
| Week 4 | 19 januari 1981 | 25 januari 1981 | even week |
| Week 5 | 26 januari 1981 | 1 februari 1981 | oneven week |
| Week 6 | 2 februari 1981 | 8 februari 1981 | even week |
| Week 7 | 9 februari 1981 | 15 februari 1981 | oneven week |
| Week 8 | 16 februari 1981 | 22 februari 1981 | even week |
| Week 9 | 23 februari 1981 | 1 maart 1981 | oneven week |
| Week 10 | 2 maart 1981 | 8 maart 1981 | even week |
| Week 11 | 9 maart 1981 | 15 maart 1981 | oneven week |
| Week 12 | 16 maart 1981 | 22 maart 1981 | even week |
| Week 13 | 23 maart 1981 | 29 maart 1981 | oneven week |
| Week 14 | 30 maart 1981 | 5 april 1981 | even week |
| Week 15 | 6 april 1981 | 12 april 1981 | oneven week |
| Week 16 | 13 april 1981 | 19 april 1981 | even week |
| Week 17 | 20 april 1981 | 26 april 1981 | oneven week |
| Week 18 | 27 april 1981 | 3 mei 1981 | even week |
| Week 19 | 4 mei 1981 | 10 mei 1981 | oneven week |
| Week 20 | 11 mei 1981 | 17 mei 1981 | even week |
| Week 21 | 18 mei 1981 | 24 mei 1981 | oneven week |
| Week 22 | 25 mei 1981 | 31 mei 1981 | even week |
| Week 23 | 1 juni 1981 | 7 juni 1981 | oneven week |
| Week 24 | 8 juni 1981 | 14 juni 1981 | even week |
| Week 25 | 15 juni 1981 | 21 juni 1981 | oneven week |
| Week 26 | 22 juni 1981 | 28 juni 1981 | even week |
| Week 27 | 29 juni 1981 | 5 juli 1981 | oneven week |
| Week 28 | 6 juli 1981 | 12 juli 1981 | even week |
| Week 29 | 13 juli 1981 | 19 juli 1981 | oneven week |
| Week 30 | 20 juli 1981 | 26 juli 1981 | even week |
| Week 31 | 27 juli 1981 | 2 augustus 1981 | oneven week |
| Week 32 | 3 augustus 1981 | 9 augustus 1981 | even week |
| Week 33 | 10 augustus 1981 | 16 augustus 1981 | oneven week |
| Week 34 | 17 augustus 1981 | 23 augustus 1981 | even week |
| Week 35 | 24 augustus 1981 | 30 augustus 1981 | oneven week |
| Week 36 | 31 augustus 1981 | 6 september 1981 | even week |
| Week 37 | 7 september 1981 | 13 september 1981 | oneven week |
| Week 38 | 14 september 1981 | 20 september 1981 | even week |
| Week 39 | 21 september 1981 | 27 september 1981 | oneven week |
| Week 40 | 28 september 1981 | 4 oktober 1981 | even week |
| Week 41 | 5 oktober 1981 | 11 oktober 1981 | oneven week |
| Week 42 | 12 oktober 1981 | 18 oktober 1981 | even week |
| Week 43 | 19 oktober 1981 | 25 oktober 1981 | oneven week |
| Week 44 | 26 oktober 1981 | 1 november 1981 | even week |
| Week 45 | 2 november 1981 | 8 november 1981 | oneven week |
| Week 46 | 9 november 1981 | 15 november 1981 | even week |
| Week 47 | 16 november 1981 | 22 november 1981 | oneven week |
| Week 48 | 23 november 1981 | 29 november 1981 | even week |
| Week 49 | 30 november 1981 | 6 december 1981 | oneven week |
| Week 50 | 7 december 1981 | 13 december 1981 | even week |
| Week 51 | 14 december 1981 | 20 december 1981 | oneven week |
| Week 52 | 21 december 1981 | 27 december 1981 | even week |
| Week 53 | 28 december 1981 | 3 januari 1982 | oneven week |
1981 heeft 53 weken, dus week 53 en week 1 van het volgende jaar zijn beide oneven.