How is the difference calculated?

The calculator finds the earlier and later date, then counts full years, remaining full months, and remaining days — just like counting on a calendar. Total days are calculated separately as the absolute difference.

Does the order of dates matter?

No. The calculator automatically detects which date is earlier and computes the positive difference. You can enter either date first.

Are leap years handled?

Yes. The calculation uses actual calendar dates, so leap years with 366 days are counted correctly. February in a leap year has 29 days.

What format should I use for dates?

Use the ISO format YYYY-MM-DD (e.g. 2026-04-07 for 7 April 2026). This ensures consistent, unambiguous parsing regardless of locale.

Can I use this for business day calculations?

This calculator counts calendar days, not business days. It includes weekends and holidays. For business-day calculations, you would need to exclude non-working days separately.

DATDate & Time

Date Difference

Find the exact difference between two dates in years, months, and days. Also shows total days, weeks, and hours between the dates.

Start date

End date

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How It Works

Formula

\text{totalDays} = \frac{\Delta t}{86400000}

\text{totalHours} = \text{totalDays} \times 24

Where

$\Delta t$: Milliseconds between the earlier and later date (UTC)
$\text{totalDays}$: Whole calendar days between the two dates
$\text{totalHours}$: Total hours between the two dates
$86400000$: Milliseconds in one day (24 × 60 × 60 × 1000)

Enter two dates. The calculator determines which is earlier, then computes the difference broken down into years, months, and days. It also calculates the total number of days, weeks, and hours between the two dates.

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