Date Difference Calculator

Calculate the difference between two dates in days, weeks, months and years

Enter Dates

Select start and end dates, then click Calculate

Total Difference

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Total Days

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Total Weeks

Weeks & Days

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Months & Days

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How to Use

  1. Select the Start Date using the date picker.
  2. Select the End Date (must be on or after the start date).
  3. Click Calculate to instantly see the difference in years, months, days, total weeks, and total days.
  4. Use the Swap button to reverse start and end dates without re-entering them.

Why Calculate the Date Difference?

Knowing the exact gap between two dates is useful in many everyday situations: calculating someone's exact age, finding out how many days until an event, tracking how long a project has taken, measuring a lease or subscription period, or counting pregnancy weeks from conception date.

How the Calculation Works

The calculator breaks the total span into years, months, and remaining days using calendar arithmetic — accounting for months of different lengths, and leap years. It also shows the total in pure days and weeks for quick reference.

Common Uses

  • Age calculation: Enter your date of birth as the start date and today as the end date.
  • Event countdown: Start = today, End = your event date — see exactly how many days remain.
  • Tenure/experience: Calculate your exact work experience for a resume or application.
  • Lease/contract duration: Verify the exact number of days in a rental or service agreement.
  • Pregnancy tracking: Start = LMP date, End = today — see gestational age in weeks and days.

Leap Year Handling

The calculator automatically accounts for leap years. A leap year occurs every 4 years (except century years not divisible by 400). For example, 2024 was a leap year (366 days), while 2100 will not be.

Frequently Asked Questions

By default the calculator counts calendar days (every day including weekends and holidays). If you need working days, subtract weekends manually or use a business-days calculator. For most personal use-cases — anniversaries, deadlines, countdowns — calendar days are the right measure.

Yes — the result shows the difference in years, months, days, total weeks, and total days. For example, 100 days = 14 weeks and 2 days. This is useful for pregnancy tracking, project timelines, or school terms.

Leap years are handled automatically. February 29 is counted as a valid day, and the extra day is included in the total. So from Jan 1 2024 to Jan 1 2025 = 366 days (2024 is a leap year).

The calculator can handle any date range supported by your browser's JavaScript Date object — effectively from year 100 to year 9999. Practically, it is accurate for all historical and future dates you are likely to need.

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