Can I add months to the end of a month?

Yes. If the target month is shorter, the result clamps to the last valid day of that month.

Can I subtract dates too?

Yes. Choose subtract, enter the amount and pick days, weeks, months or years.

Can I turn the result into a countdown?

Yes. Open the countdown from the result to track time until that date.

Date Calculator

Add or subtract days, weeks, months and years from any date.

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Answer Ready

Choose dates to calculate.

Start date End date Include end date

Start date Operation Amount Unit

Date of birth Age on

Start date End date Include end date

Open countdown

Calculation rules

Days and weeks are added as exact calendar-day steps. Months and years use real calendar dates, so end-of-month results clamp to the last valid day when the target month is shorter. That keeps impossible dates from rolling into the following month.

Input	Result rule
January 31 + 1 month	February 28, or February 29 in a leap year.
March 31 - 1 month	February 28, or February 29 in a leap year.
February 29 + 1 year	February 28 when the target year is not a leap year.

Related date tools

Days between dates Age calculator Business days Create countdown

Questions

Can I add months to the end of a month?: Yes. If the target month is shorter, the result clamps to the last valid day of that month.
Can I subtract dates too?: Yes. Choose subtract, enter the amount and pick days, weeks, months or years.
Can I turn the result into a countdown?: Yes. Open the countdown from the result to track time until that date.

Use it with confidence

Quick operating notes for this browser-based tool.

Keyboard: Use Tab to move through controls and Enter or Space to activate them. This tool has no global shortcuts.
Mobile: Controls are touch-sized and stack on narrow screens. Rotate the device only when a wider view helps.
Offline: The calculation runs in your browser. The route must have loaded once before it can reopen from cache without a connection.
Browser limits: Date results use local calendar values in the browser; confirm timezone and date inputs before relying on the answer.