Date & Time Calculator
Days in Month Calculator
Find the number of days in any month and year.
Calculator
Results
Days in month
30
MonthSeptember
Year2026
Leap year?No
Results are calculated instantly in your browser using the inputs shown. Date and time calculations follow the stated assumptions below.
How it works
Find the number of days in any month and year.
Days in month = last calendar day of the selected month. February has 29 days in leap years and 28 otherwise.
Example
| Example | Result |
|---|---|
| September 2026 has 30 days. | See calculator |
Important notes
- Calendar calculations use Gregorian calendar rules.
- Business-day calculations exclude Saturday and Sunday unless stated otherwise.
- Time-zone calculations depend on the browser's IANA time-zone data.
- For planning purposes, verify dates and times when a contractual or legal deadline is involved.
Frequently Asked Questions
How many days does February have?
28 in a common year and 29 in a leap year.
Does this use Gregorian leap-year rules?
Yes.
How to use this calculator
What to enter
Enter or select the following as requested: Month; Year. Follow the units, valid ranges, examples, and options displayed beside each field.
What the result means
The date or duration result is calculated from the entered dates, times, calendar rules, and exclusions. Check inclusive versus exclusive counting, time zone, daylight-saving changes, and whether weekends or holidays are excluded.
When to use it
Use this to plan a date, measure elapsed time, or estimate a deadline. Verify the relevant calendar, location, and legal or workplace rules when they affect the answer.