Week 40 of 2025

September 29, 2025 (Monday) to October 5, 2025 (Sunday)

← Week 39 Week 40 of 2025 Week 41 →
ISO Week Number
Week 40
2025 · Week 40 of 52 total weeks

What dates are in Week 40 of 2025?

Week 40 of 2025 runs from September 29, 2025 (Monday) to October 5, 2025 (Sunday). This is the 40th week of the year according to the ISO 8601 standard, in which weeks start on Monday.

Mon
Sep 29
Day 272
Tue
Sep 30
Day 273
Wed
Oct 1
Day 274
Thu
Oct 2
Day 275
Fri
Oct 3
Day 276
Sat
Oct 4
Day 277
Sun
Oct 5
Day 278
Starts September 29, 2025 Monday · Day 272
Ends October 5, 2025 Sunday · Day 278
Duration 7 days 2025 · 52-week year

📅 Nearby weeks in 2025

Week 38Week 39Week 40Week 41Week 42

📋 All 52 weeks in 2025

12345·678910·1112131415·1617181920·2122232425·2627282930·3132333435·3637383940·4142434445·4647484950·5152

📆 Week 40 in other years

Week 40 · 2024Week 40 · 2026

🔧 Related tools

Week Number Calculator Date to Week 2025 Full Calendar

❓ Related questions about Week 40 of 2025

What day of the week is Sep 29?

Sep 29 is a Monday. It is the first day of Week 40 of 2025.

What day of the week is Oct 5?

Oct 5 is a Sunday. It is the last day of Week 40 of 2025.

What is the ISO week number for Sep 29?

Sep 29 is in Week 40 of 2025 according to ISO 8601.

What is the ISO week number for Oct 5?

Oct 5 is in Week 40 of 2025 according to ISO 8601.

❓ Frequently asked questions about Week 40 of 2025

What dates are in Week 40 of 2025?

Week 40 of 2025 runs from September 29, 2025 to October 5, 2025.

Which day of the year does Week 40 start on?

Week 40 of 2025 starts on September 29, 2025, the 272th day of 2025.

Does Week 40 of 2025 fall entirely within 2025?

Yes, all 7 days of Week 40 of 2025 fall within 2025.

How many weeks are in 2025?

2025 has 52 weeks according to ISO 8601.