Date Difference Calculator

Calculate the exact difference between two dates in years, months, weeks, days, hours, and minutes. See weekdays vs weekends.

Free to use. Runs in your browser.

Select two dates to instantly see the difference in years, months, weeks, days, hours, and minutes, plus weekday/weekend breakdown.

Start Date

End Date

Why Date Calculations Are Harder Than They Look

Counting days between dates sounds trivial until you actually think about it. Months have 28, 29, 30, or 31 days. Years are 365 days, except leap years, which are 366. And "one month from January 31st" doesn't neatly land on February 31st because that date doesn't exist.

This calculator handles all of that complexity. It uses the date-fns library to correctly compute differences across month boundaries, leap years, and varying month lengths. The result breaks down into years, months, weeks, and remaining days, plus total counts in each unit separately for when you need a single number.

It also splits the count into weekdays and weekends, which is useful for project planning and business calculations. If you need only business days, use our dedicated Business Days Calculator.

Quick Reference: Days in Each Month

Month	Days	Month	Days
January	31	July	31
February	28/29	August	31
March	31	September	30
April	30	October	31
May	31	November	30
June	30	December	31

What this means for you: February is the wildcard, 28 days normally, 29 in leap years (every 4 years, except centuries not divisible by 400). The next leap year is 2028.

When You Need Date Differences

Age Verification

Calculate exact age in years, months, and days from a date of birth. Useful for forms, legal age checks, and milestone tracking.

Contract Duration

How long has a lease been running? When does the notice period end? Date differences remove the guesswork from legal timelines.

Travel Planning

Knowing the exact number of nights between departure and return dates helps with hotel bookings, travel insurance, and itinerary planning.

Fitness & Health Tracking

Track how many days you've been on a programme, how long until a race, or the gap between medical appointments.

Common Date Difference Calculations

Scenario	Typical Duration	Watch For
UK notice period (1 month)	28-31 days	Calendar month, not 30 days
Probation period (3 months)	89-92 days	Check if it's calendar or working days
Standard pregnancy	280 days (40 weeks)	Counted from last menstrual period
UK passport renewal	3-10 weeks	Longer during peak periods
Cooling-off period (online)	14 days	Calendar days from delivery date

Related Tools

Business Days Calculator

Count working days between dates

Countdown Calculator

Count down to any future date

Age Calculator

Calculate exact age from date of birth

Time Zone Converter

Convert times between time zones

Work Hours Calculator

Calculate weekly work hours

Unix Timestamp Converter

Convert Unix timestamps to dates

How to use this tool

Enter the start date

Enter the end date

Click Calculate to see the full breakdown

Common uses

Calculating exact age or time elapsed since a date
Determining contract and lease durations
Planning travel with accurate day counts
Tracking time between medical appointments or milestones

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Frequently Asked Questions

Does the order of dates matter?

No. If you enter the later date first, we automatically swap them to give the correct difference.

Are leap years accounted for?

Yes. The date-fns library correctly handles leap years, varying month lengths, and all calendar edge cases.

What counts as a weekday?

Monday through Friday are weekdays. Saturday and Sunday are weekends. The breakdown shows both counts separately.

Can I calculate business days?

The weekday count shows working days excluding Saturdays and Sundays, but not public holidays. For holiday-aware calculations, use our Business Days Calculator.

Why is the month count different from dividing days by 30?

Months aren't uniform, they range from 28 to 31 days. The calculator uses calendar-aware month counting, not simple division. January 15 to March 15 is exactly 2 months, regardless of February's length.

How does it handle time zones?

It uses date-only calculations (no time component), so time zones don't affect the day count. Both dates are treated as midnight in your local zone.

Can I find the difference in hours or minutes?

Yes. The results include total hours and total minutes alongside the year/month/day breakdown.

What's the maximum date range?

You can calculate differences between any two valid dates your browser supports, typically from year 0001 to 9999.

Why might my weekday count not match a manual count?

The calculator includes both the start and end dates. If one or both fall on a weekend, the weekday count may be one less than you'd expect from a simple range.

Can I use this for age calculation?

Yes, though our dedicated Age Calculator provides a more focused experience for age-related calculations including zodiac signs and milestones.

Does it show the result in work weeks?

The total weeks figure divides all days (including weekends). For work weeks, divide the weekday count by 5.

Is my data stored anywhere?

No. All calculations run in your browser. Your dates are never transmitted or saved.

Results are for general informational purposes only and should be checked before use. They are not professional advice. See our Disclaimer and Terms of Service.