How is the difference between two dates calculated?

The calculator counts every calendar day from the start date to the end date inclusive, including leap days. The result is also expressed in weeks, months and years, and broken into a Y-M-D component count.

Are weekends and holidays included in the day count?

Calendar days include weekends. The calculator also reports the equivalent in working days (Monday–Friday), which excludes weekends. Public holidays are not subtracted automatically because they vary by country.

How do I add 30 days to today?

Use the 'Add or subtract' tab. Pick today's date, select 'Add', enter 30 in the days field, and the calculator returns the future date.

Why are months and years approximate?

Calendar months have between 28 and 31 days. The calculator returns whole months/years (counting from the same calendar date) plus a remainder in days, which is exact.

📅 Date Difference Calculator

Find the exact number of days between two dates, or add and subtract days from any date.

Start date

End date

ℹ️ Tip. "Working days" counts Monday to Friday only. Public holidays vary by country and are not auto-excluded.

About the Date Difference Calculator

The Date Difference Calculator answers the everyday questions: "how many days between two dates?", "what date is 30 days from now?", and "how many working days until the deadline?". All calculations run locally in your browser — no data is shared.

Mode 1 — Between two dates

Pick a start and end date. The calculator returns:

Total calendar days — including weekends and any leap day in between
Working days — Monday to Friday only
Weeks, months and years — calendar-aware (a year is the same date next year, regardless of length)
Years, months and days — broken-down "Y years, M months, D days" form
Hours — total elapsed hours assuming midnight on each date

Mode 2 — Add or subtract days

Pick a base date, choose Add or Subtract, and enter a number of days. The calculator returns the resulting date in ISO format (YYYY-MM-DD), the day of the week, the day of the year (1–366) and the ISO 8601 week number.

Common uses

Project deadlines — count working days to a milestone
Visa, passport and travel paperwork — compute "X days before/after" requirements
Returns and warranties — when does the 30-day return window expire?
Pregnancy week tracking — see also our Pregnancy Due Date Calculator
Anniversaries, countdowns and event planning
Legal and contract notice periods

Frequently Asked Questions

Are leap days handled correctly? Yes. The calculator counts every calendar day, including 29 February in leap years.

Why does "1 year" sometimes appear as 365 days and sometimes 366? A year is treated as the same calendar date next year. If a leap day falls in the interval the equivalent total in days is 366 rather than 365.

Are public holidays excluded from working days? No — they vary by country. The "working days" count only excludes Saturdays and Sundays. If you need a country-specific business-day count, subtract the official holiday count manually.

How do I count from today? All date pickers default to today on first load. Just change the other date.

Is the data private? Yes — all calculations run entirely in your browser and nothing is uploaded.

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Important Note: This tool is intended to provide estimates and should not be used as a substitute for professional advice. Information generated by these calculators may be incomplete and does not account for all individual circumstances. Always seek the counsel of a certified expert (such as a financial advisor, healthcare provider, or licensed engineer) before taking action based on these results.

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