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Time & Duration

Advanced Days Calculator

The ultimate tool for date arithmetic. Calculate exact differences, skip weekends (business days), or add/subtract time units from any date instantly.

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Date Difference Add / Subtract

Total Duration

-

Alternative Units

Distribution

Target Date Day

Monday

Mastering Date Calculations

Counting days might seem simple, but when leap years, different month lengths, and business hours come into play, errors are common. This advanced tool removes the guesswork.

Business Days vs Calendar Days

By default, calendar days count every single day from start to finish. Business days (Commonly Mon-Fri) are essential for HR systems, logistics, and legal deadlines.

Date Arithmetic Explained

Want to know where you'll be in exactly 100 days? Or what 6 months ago was? Use the Add / Subtract tab to find target dates by shifting time forward or backward.

How does "Include End Day" work?

Normally, calculators subtract one date from another. Feb 1 to Feb 2 is 1 day. If you check "Include End Day", it counts both as active days, resulting in 2 days.

Are leap years supported?

Yes. Our logic uses the JavaScript Date object which fully supports Gregorian leap year rules (like 2024 or 2028).

Can I calculate work days?

Absolutely. Toggle "Business Days Only" to automatically filter out all Saturdays and Sundays from your result.