Date Calculator

How to use the date calculator

1. Choose Days between dates, Add days to a date or Subtract days from a date.
2. Select the required dates, or select one date and enter a whole number of days. Today uses the current date on your device when you press it.
3. Read the answer and its counting rule. For a date difference, turn on Count both dates only if you want to include both date labels. Copy or print the qualified result if you need it.

A simple calendar-day calculator

• Three everyday tasks share one small form. Only the two values needed for the selected task are shown.
• Days between dates accepts either date order. The optional inclusive count is shown explicitly, so you can see which convention was used.
• Adding and subtracting days follows actual Gregorian month lengths and leap years. You do not need to convert days into weeks or months.
• Your entries stay in the calculator's memory. The calculation does not require sending dates to a calculation service; the surrounding website still uses its normal assets and consent-controlled integrations.

When a date calculator helps

• Find the calendar-day gap between two personal milestones without counting each month by hand.
• Work out an ordinary future or past date, such as 30 days after a chosen starting date.
• Count all date labels in a period when both endpoints matter. For hotel nights, billing terms, working days or official deadlines, use the relevant rules rather than assuming this answer applies.

What the result means

The standard difference is the absolute gap between the dates. From 1 April to 2 April it is 1 day; reversing the two dates keeps the answer at 1 day. Two equal dates have a difference of 0 days.

Count both dates adds 1 to that difference. From 1 April to 2 April the inclusive count is 2 days. Two equal dates count as 1 day. This option does not change the add-days or subtract-days tasks.

When shifting a date, the starting date is day zero: adding 1 day gives the following date, subtracting 1 gives the previous date, and 0 leaves the date unchanged. The result is a calendar date, not an exact 24-hour duration.

The calculator uses the proleptic Gregorian calendar: Gregorian month and leap-year rules apply across the whole supported range. It does not switch calendars at a country's historical adoption date, skip dates changed by local time-zone policy or adjust for weekends and holidays.

Checked examples

From 8 October 2026 to 7 November 2026, the difference is 30 days. Counting both dates gives 31 days. Reversing the dates gives the same respective counts.

Adding 30 days to 8 October 2026 gives 7 November 2026. Subtracting 30 days from 7 November 2026 returns 8 October 2026.

Adding 1 day to 28 February 2024 gives 29 February 2024, because 2024 is a leap year. Adding 1 day to 28 February 2025 gives 1 March 2025.

Subtracting 1 day from 1 January 2027 gives 31 December 2026. Adding 0 days to 1 January 2027 keeps the result at 1 January 2027.

Limits and counting conventions

Supported dates run from 0001-01-01 to 9999-12-31. A day amount must be a whole number from 0 to 3652058. A shift that leaves the date range is rejected, not shortened or wrapped around.

There are no working-day, holiday, time-of-day or time-zone settings. A spring clock change does not turn a date difference into a 23-hour count; the tool counts Gregorian date labels.

This is a general calendar aid, not an authoritative deadline, visa-stay, age-eligibility, accommodation-night or billing calculator. For ancient or historical records, check the calendar actually used in the source.

Your entries and copied results

Entered dates and day amounts are not placed in the page address or saved by this calculator. Switching language through the site's normal navigation may reload the page and clear them.

Copy and Print include the task, entered values, result and counting convention. Once copied to your system clipboard or handed to the browser's print dialog, a summary cannot be recalled by editing the calculator.