Days in Month Calculator
Instantly calculate the number of days in any month and year. Check for leap years, find the first and last weekday, and plan your schedule accurately.
Calculate Days in Any Month
Select a month and year below to instantly see the total number of days, whether it is a leap year, and the exact weekdays the month begins and ends on.
Select Date Parameters
Choose your target month and year
Calendar Evaluation
Detailed breakdown for your selected period
How Month Lengths Are Determined
The Gregorian calendar, used universally today, follows specific astronomical and historical rules to determine the length of each month.
The Solar Year
Earth takes approximately 365.2422 days to orbit the Sun. Our calendar rounds this to 365 days, adding an extra day every four years to prevent seasonal drift over centuries.
Historical Origins
Month lengths date back to the Roman calendar. July and August were named after Julius Caesar and Augustus, both given 31 days to reflect their importance, altering the original sequence.
Leap Year Rules
A year is a leap year if divisible by 4. However, century years (like 1900) are not leap years unless they are also divisible by 400 (like 2000). This keeps the calendar accurate.
Standard Days per Month
A quick lookup table for the number of days in each month during both common and leap years.
| Month | Common Year | Leap Year |
|---|---|---|
| January | 31 days | 31 days |
| February | 28 days | 29 days |
| March | 31 days | 31 days |
| April | 30 days | 30 days |
| May | 31 days | 31 days |
| June | 30 days | 30 days |
| July | 31 days | 31 days |
| August | 31 days | 31 days |
| September | 30 days | 30 days |
| October | 31 days | 31 days |
| November | 30 days | 30 days |
| December | 31 days | 31 days |
Calendar & Leap Year FAQ
Everything you need to know about calculating days, months, and leap years.
January, March, May, July, August, October, and December have 31 days. April, June, September, and November have 30 days. February has 28 days in a common year and 29 days in a leap year.
A year is a leap year if it is evenly divisible by 4. However, if the year is also divisible by 100, it is not a leap year, unless it is also divisible by 400. For example, 2000 was a leap year, but 1900 was not.
A solar year (the time it takes Earth to orbit the Sun) is approximately 365.2422 days. Adding an extra day to February every four years helps keep our calendar year synchronized with the astronomical year.
Yes. Simply select your desired month and year, and the calculator will instantly display the exact weekday for both the first and last day of that month, along with the total number of days.