Productivity & Planning

Date & Duration Calculator

Date difference, add/subtract, working days, age and deadlines.

Difference between two dates

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About Date & Duration Calculator

Everything you need to calculate with dates: difference between two dates in years, months and days, add or subtract durations, count working days excluding weekends and holidays, compute exact age, find week numbers and plan deadlines.

What it does

How to use it

  1. Pick the calculation from the tabs: difference, add or subtract, working days, or age.
  2. Enter the dates involved.
  3. Results appear immediately with a full breakdown in years, months, days, weeks and hours.
  4. Add your own holiday list so business-day counts match your office calendar.

Date & Duration Calculator is one of 50 free tools from CRMTECH Solutions. See all Productivity & Planning tools or browse every tool.

Frequently asked questions

How is the difference in years and months calculated?

Calendar-aware, the way a person counts. From 31 January to 28 February is one month, not 28 days divided by 30. The tool walks forward month by month and then counts the leftover days, which matches how contracts and notice periods are read.

Which days count as working days?

Monday to Friday by default, minus any dates in your holiday list. You can switch to a six-day week or mark alternate Saturdays, which many Indian offices use.

Does the age calculator handle leap years?

Yes. Someone born on 29 February has their age incremented on 28 February in common years, which is the convention used for most legal and administrative purposes in India.

Can I add business days rather than calendar days?

Yes. The Add and subtract tab has a business-day mode that skips weekends and holidays, which is how delivery and SLA deadlines are usually expressed.

Are the calculations affected by time zones?

No. All arithmetic is done on calendar dates at local midnight, so daylight-saving transitions and time zones cannot shift a result by a day.

Is Date & Duration Calculator free?

Yes. Date & Duration Calculator is free for everyone and needs no sign-up to use. An account is only needed to export, download or print, because every export is recorded.

Are my files uploaded to a server?

No. Date & Duration Calculator works inside your web browser, so the files you open are processed on your own device. If you sign in, the work you save (such as drafts and registers) is also kept in your account so it follows you to other devices.

Does it work on a phone?

Yes. It works in current versions of Chrome, Edge, Safari and Firefox on phones, tablets and computers, with nothing to install.