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Date Difference Calculator

Measure the exact gap between two dates in years, months, days, weeks, and business days.

How this calculator works

Pick any two dates and the calculator reports the gap four ways: a calendar-accurate breakdown in years, months, and days; the total number of days; the equivalent in weeks plus leftover days; and an approximate count of business days (five-sevenths of the total). Enter the dates in either order — it measures the distance between them regardless.

The calendar breakdown respects real month lengths and leap years rather than assuming every month has 30 days, so the answer matches what you'd get counting forward on a physical calendar.

Worked example

From 15 January 2026 to 20 July 2026 is 6 months and 5 days — 186 total days, or 26 weeks and 4 days, roughly 133 business days. That's the difference between "about six months" and a number you can actually plan a project, notice period, or visa application around.

Everyday uses

  • Deadlines and notice periods — exactly how many days between signing and completion, or between resignation and last day.
  • Billing and prorating — count the precise days in a partial rental or subscription period.
  • Countdowns — days until a wedding, race, exam, or product launch.
  • Durations in hindsight — how long a project, job, or trip really lasted.

A note on the business-days figure

The business-day count is an approximation: it scales the total by 5/7 without knowing which weekday the range starts on, and it can't account for public holidays, which vary by country. For contractual deadlines defined in working days, verify against a calendar for your jurisdiction — but for planning purposes the approximation is normally within a day or two.

Frequently asked questions

Are both the start and end dates counted?

The calculator measures elapsed time between the two dates — from the start date up to (but not including) the end date. So 1 January to 2 January is 1 day. If your context counts both endpoints inclusively, add one to the total.

Does it account for leap years?

Yes. Total days are computed from real calendar dates, so 29 February is included whenever the range crosses one, and the years/months/days breakdown borrows correctly across months of different lengths.

How accurate is the business-days estimate?

It assumes exactly five working days per seven calendar days and ignores public holidays, so treat it as an estimate within a day or two. For legal or contractual working-day deadlines, count against an official calendar for your country.