Days Between Dates Calculator

Count the days, weeks, months and business days between two dates — right in your browser.

How to use

  1. Pick the start date and the end date — the order does not matter, the tool always counts forward from the earlier one.
  2. Read the total in calendar days, plus the breakdown in weeks and days, months and days, and years, months and days.
  3. The business-day count (Monday to Friday) appears beside it. Everything is calculated in your browser.

About this tool

Counting the days between two dates looks like simple subtraction until the calendar gets in the way: months have 28, 29, 30 or 31 days, February changes length every four years, and daylight saving shifts the clock without changing the date. This calculator handles all of it and answers the question in four different shapes at once — total days, weeks plus days, months plus days, and the full years-months-days breakdown that people actually use to describe a period of time.

Internally each date is converted to a Julian day number, an integer that counts days on a continuous line, and the difference is a plain subtraction. That makes the result immune to time zones and daylight saving. The calendar breakdown is not an approximation: instead of dividing by 30, the tool finds the largest whole number of months that fits between the two dates — clamping to the end of shorter months, so 31 January to 1 March is one month and one day — and then counts the days left over.

The business-day figure counts only Mondays to Fridays, using whole weeks times five plus the remaining weekdays. Public holidays are not included: they differ by country, state and city, and a generic tool that guessed them would be wrong more often than right. For deadlines that depend on official holidays, use this number as the starting point and subtract the holidays that apply to you. Both dates stay on your device — the page performs no network requests with your data.

The formula

Calendar days = JDN(end) − JDN(start), where JDN is the Julian day number of each date. Calendar breakdown: take the largest whole number of months M that fits between the dates (clamping the day to the last day of shorter months), then years = M ÷ 12, months = M mod 12, and days = the remainder in days. Business days = ⌊days ÷ 7⌋ × 5 + the Monday-to-Friday days left in the incomplete week.

Frequently asked questions

Does the count include the first and the last day?

It counts the days elapsed between the two dates, so the start day is not counted and the end day is. From 1 March to 3 March the answer is 2 days. If you need the number of days a period occupies — the classic "counting both ends" — add 1 to the result.

Why is the difference in months not just the days divided by 30?

Because real months are not 30 days long. Dividing by 30 drifts by about five days per year. The tool walks the calendar month by month instead, which is why 1 January to 1 March is exactly 2 months even though it can be 59 or 60 days.

Are public holidays subtracted from the business days?

No. The business-day count only removes Saturdays and Sundays. Holidays vary by country and even by city, so the tool does not guess them — subtract the ones that apply to your case.

Does it handle leap years and daylight saving?

Yes. Leap days are counted like any other day, and the calculation uses whole-day arithmetic, so a clock change never adds or removes a day from the total.

Do my dates leave my browser?

No. The whole calculation runs in JavaScript on your device. Nothing is uploaded, logged or stored.

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