Date Difference Calculator

Measure the gap between two dates

How long have you been in a job, how old is a project, how long is left on a lease? Enter a start date and an end date and the calculator shows the gap the way people say it — years, months, and days — plus the total number of days and weeks. The dates can be in either order. If you only need a day count, the Days Between Dates Calculator is simpler.

How to use the Date Difference Calculator

1. Choose the start date.
2. Choose the end date. If it is earlier than the start date, the calculator measures the same gap and notes that the dates are reversed.
3. Read the difference, the total days, and the weeks and days. Copy Result copies a one-line summary.

The method

Months have 28 to 31 days, so a month can’t be turned into a fixed number of days. The calculator counts forward from the earlier date in whole calendar months and then counts the days that remain. When the starting day doesn’t exist in a month — there is no February 31 — the month ends on that month’s last day, which is why January 31 to February 28 is exactly one month.

Calculated on your device

• The calculation runs in your browser as you choose the dates; nothing is sent to a server.
• The dates you enter and the results are not sent to Looty Tools or stored.
• The calculator area is masked from session-recording analytics, so what you enter isn’t captured in recordings.

Limitations

• The end date isn’t added as an extra day: January 1 to January 2 is 1 day. To count both dates, use the Days Between Dates Calculator.
• Month-end dates follow the last-day rule, so another calculator may split the same dates into months and days differently; the total days is the same either way.
• Calendar dates only — no times of day or time zones.
• Gregorian calendar, years 1 to 9999.

Related calculators

• Age CalculatorFind an age from a birth date.
• Days Between Dates CalculatorCount the days from one date to another.

Date Difference Calculator FAQ

How is the difference between two dates calculated?

Starting from the earlier date, the calculator counts whole years, then whole months, then the days left over. The total days counts every calendar day from one date to the other.

How is this different from the Days Between Dates Calculator?

This one breaks the gap into years, months, and days, which suits ages, anniversaries, and contract lengths. Days Between Dates gives a single day count, with an option to count both the start and end dates.

What if the end date is before the start date?

You get the same difference as with the dates the other way round, plus a note that the end date is earlier. The result is never negative.

Why is January 31 to February 28 exactly one month?

When the starting day doesn’t exist in the target month, the month is counted as complete on that month’s last day. Other tools sometimes count this differently, so month-end results can vary between calculators.

Is the end date counted?

The difference is measured from the start date to the end date, like subtraction: January 1 to January 2 is 1 day. To count both days, use the Days Between Dates Calculator with “Include end date”.

Do leap years or daylight saving time affect the result?

Leap days are counted whenever they fall between the dates. Daylight saving time can’t affect it, because the calculator works with calendar dates rather than clock times.

Are the dates and times I enter sent anywhere?

No. The calculation runs in your browser as you type. The dates and times you enter and the results are not sent to Looty Tools or stored, and the calculator area is masked from session-recording analytics. Refreshing the page clears it.