Seven months have 31 days (January, March, May, July, August, October, December), four have 30 days (April, June, September, November), and February has 28 days, or 29 in a leap year.
30.4369 days
1 month = 30.4369 days
| Unit | Amount |
|---|---|
| Milliseconds | 2,629,746,000 |
| Seconds | 2,629,746 |
| Minutes | 43,829.1 |
| Hours | 730.485 |
| Days | 30.4369 |
| Weeks | 4.3481 |
| Years | 0.0833 |
| Decades | 0.0083 |
| Centuries | 0.0008333 |
A month is 30.436875 days on average (a year ÷ 12). Calendar months have 28 to 31 days.
How it’s calculated
Every unit is converted through seconds: 1 minute = 60 s, 1 hour = 3,600 s, 1 day = 86,400 s, 1 week = 604,800 s. Months and years use the Gregorian average: 1 year = 365.2425 days = 31,556,952 s, 1 month = 1/12 year = 2,629,746 s.
Worked example with your numbers
- 1 month × 2,629,746 seconds per month = 2,629,746 seconds.
- 2,629,746 seconds ÷ 86,400 seconds per day = 30.4369 days.
Quick answer
Seven months have 31 days (January, March, May, July, August, October, December), four have 30 days (April, June, September, November), and February has 28 days, or 29 in a leap year.
- 31 days
- 7 months
- 30 days
- 4 months
- February
- 28 or 29 days
- Average
- 30.44 days
| Month | Days | Weeks | Hours | Weekdays |
|---|---|---|---|---|
| January | 31 | 4 weeks + 3 days | 744 | 22 |
| February | 28 | 4 weeks + 0 days | 672 | 20 |
| March | 31 | 4 weeks + 3 days | 744 | 22 |
| April | 30 | 4 weeks + 2 days | 720 | 22 |
| May | 31 | 4 weeks + 3 days | 744 | 21 |
| June | 30 | 4 weeks + 2 days | 720 | 22 |
| July | 31 | 4 weeks + 3 days | 744 | 23 |
| August | 31 | 4 weeks + 3 days | 744 | 21 |
| September | 30 | 4 weeks + 2 days | 720 | 22 |
| October | 31 | 4 weeks + 3 days | 744 | 22 |
| November | 30 | 4 weeks + 2 days | 720 | 21 |
| December | 31 | 4 weeks + 3 days | 744 | 23 |
Average month (365.2425 ÷ 12): 30.436875 days = 4.348 weeks = 730.485 hours. “Thirty days hath September, April, June and November; all the rest have thirty-one, except February” — 28 days, 29 in a leap year.
How it works
The knuckle trick: make two fists and count months across the knuckles and the gaps between them — months on a knuckle have 31 days, months in a gap have 30 (or 28/29 for February).
Frequently asked questions
Which months have 31 days?
January, March, May, July, August, October and December.
Which months have 30 days?
April, June, September and November.