End of Month Calculator
Find the last calendar day of any month for any year, with leap-year support.
How to use this tool
- Enter any date in the month in the fields above.
- Results update instantly as you type — or click Calculate.
- Read your last day of month and the full breakdown beneath it.
Find the last calendar day of any month for any year, with leap-year support.
How it works
This tool returns the last calendar day of the month for any date you enter. For example, if you enter any date in March 2025, the tool returns March 31, 2025. For any date in February 2024, it returns February 29, 2024 (a leap year).
Enter any date within the month you are interested in. The tool identifies the month and year, then looks up the correct number of days in that month (accounting for leap years for February) and returns the final date.
This is commonly used in accounting to close a ledger period, in database queries to build date ranges that end on the last day of a month, in payroll to calculate pay period end dates, and in financial models that reference month-end values.
The tool also shows the day of the week the month end falls on, which is useful for scheduling month-end meetings or knowing whether the deadline lands on a weekend.
Worked example
Find the last day of the current quarter for closing books
- Enter any date in September: 2025-09-10
- Click Calculate
- Result: September 30, 2025
- Note: September 30, 2025 is a Tuesday
September 30, 2025 (Tuesday)
Common mistakes to avoid
- Assuming February always ends on February 28 -- in leap years it ends on February 29.
- Using a fixed value like the 30th for month-end calculations in months that have 31 days.
- Not checking whether the month-end falls on a weekend when scheduling dependent tasks.
Key terms
- Month-end date
- The last calendar day of a specific month, used as a reference point in financial reporting and scheduling.
- Period close
- The accounting process of finalizing transactions for a reporting period, typically done on or just after the month-end date.
Frequently asked questions
- Does this handle February in leap years?
- Yes — it returns February 29 in leap years and February 28 in common years.
- How do I use this?
- Pick any date within the month you are interested in. The calculator always returns the last day of that month.