Week 40 of 2026

September 28, 2026 (Monday) to October 4, 2026 (Sunday)

← Week 39 Week 40 of 2026 Week 41 →
ISO Week Number
Week 40
2026 · Week 40 of 53 total weeks

What dates are in Week 40 of 2026?

Week 40 of 2026 runs from September 28, 2026 (Monday) to October 4, 2026 (Sunday). This is the 40th week of the year according to the ISO 8601 standard, in which weeks start on Monday.

Mon
Sep 28
Day 271
Tue
Sep 29
Day 272
Wed
Sep 30
Day 273
Thu
Oct 1
Day 274
Fri
Oct 2
Day 275
Sat
Oct 3
Day 276
Sun
Oct 4
Day 277
Starts September 28, 2026 Monday · Day 271
Ends October 4, 2026 Sunday · Day 277
Duration 7 days 2026 · 53-week year

📅 Nearby weeks in 2026

Week 38Week 39Week 40Week 41Week 42

📋 All 53 weeks in 2026

12345·678910·1112131415·1617181920·2122232425·2627282930·3132333435·3637383940·4142434445·4647484950·515253

📆 Week 40 in other years

Week 40 · 2025Week 40 · 2027

🔧 Related tools

Week Number Calculator Date to Week 2026 Full Calendar

❓ Related questions about Week 40 of 2026

What day of the week is Sep 28?

Sep 28 is a Monday. It is the first day of Week 40 of 2026.

What day of the week is Oct 4?

Oct 4 is a Sunday. It is the last day of Week 40 of 2026.

What is the ISO week number for Sep 28?

Sep 28 is in Week 40 of 2026 according to ISO 8601.

What is the ISO week number for Oct 4?

Oct 4 is in Week 40 of 2026 according to ISO 8601.

❓ Frequently asked questions about Week 40 of 2026

What dates are in Week 40 of 2026?

Week 40 of 2026 runs from September 28, 2026 to October 4, 2026.

Which day of the year does Week 40 start on?

Week 40 of 2026 starts on September 28, 2026, the 271th day of 2026.

Does Week 40 of 2026 fall entirely within 2026?

Yes, all 7 days of Week 40 of 2026 fall within 2026.

How many weeks are in 2026?

2026 has 53 weeks according to ISO 8601.