Skip to content
Lizely

Date Difference Calculator

Count days, weeks, and months between any two dates.

Privacy: your files never leave your device. All processing happens locally in your browser.

How to use

  1. 1.Pick your start date in the first field (it defaults to today).
  2. 2.Pick your end date in the second field.
  3. 3.Read the days, weeks, months, and years-months-days breakdown instantly below, and tick "weekdays only" to exclude weekends.

About Date Difference Calculator

This date difference calculator tells you exactly how many days between two dates the moment you pick them. Enter a start date and an end date and the answer updates live, with no button to press: the total number of days, the number of weeks between the dates, the total number of whole months, and a plain years, months, and days breakdown so you can read the gap the way people actually say it, such as 1 year, 2 months, and 5 days.

The total days figure is the calendar difference between the two dates. So January 1, 2020 to March 1, 2020 is 60 days, because 2020 is a leap year and February has 29 days that year; in a non-leap year the same span is 59 days. Picking the same date twice returns zero. If you accidentally enter the later date first, the tool measures the gap either way and never shows a negative number, so you always get a clean, positive answer.

The years, months, and days breakdown is calendar-correct rather than a rough division. It is built the same way the date-fns intervalToDuration function works: it fills whole years first, then whole months, then the leftover days, moving the anchor forward at each step. That avoids the classic off-by-one errors you get from naive subtraction around month ends and leap days. Month lengths and leap years follow the full Gregorian rule (divisible by 4, except centuries unless divisible by 400), so February 29 is handled correctly, and the breakdown always adds back up: start date plus the years, months, and days lands exactly on the end date.

Weeks between dates are shown as whole weeks, calculated as the total days divided by seven and rounded down, so 60 days is 8 weeks with a few days left over. Total months counts only complete months, using the same end-of-month clamping as adding months to a date, so a span that is one day short of a full month is not rounded up.

Turn on the optional weekdays only mode to split the span into working days and weekend days. Weekdays are Monday to Friday; Saturdays and Sundays are excluded. The two counts always add up to the total days, which makes it easy to estimate working time for a project, a delivery window, or a notice period. This is a general weekday count and does not subtract public holidays; for a holiday-aware working-day count, use a dedicated business-days calculator.

Common uses include working out how many days until a deadline, how long ago something happened, the length of a trip, a project, a pregnancy, or a subscription term, and how many weeks or months are between two milestones. Everything runs in your browser, so the dates you enter never leave your device and nothing is uploaded, stored, or sent anywhere. There is no signup and no limit on how many calculations you run. To add or subtract time from a single date instead, use a date add-subtract calculator; to work out an age or anniversary from a birth date, use an age calculator; and to find which weekday a date falls on, use a day-of-week calculator.

Frequently asked questions

How many days between two dates does this show?
It shows the exact calendar difference in days between the start and end date, updated the moment you pick them. For example, January 1, 2020 to March 1, 2020 is 60 days because 2020 is a leap year, and the same dates in a non-leap year are 59 days.
How do I find the number of weeks between dates?
The tool shows weeks between the dates automatically as whole weeks, calculated as the total number of days divided by seven and rounded down. So a 60-day gap is shown as 8 weeks, with the leftover days included in the total days figure.
What does the years, months, and days breakdown mean?
It expresses the gap the way people speak, such as 1 year, 2 months, and 5 days. It fills whole years first, then whole months, then leftover days, using the same clamping as date-fns intervalToDuration, so the parts always add back up to the end date exactly.
Does it handle leap years and February 29?
Yes. Month lengths use the full Gregorian rule, so February has 29 days when the year is divisible by 4 but not 100 unless also by 400. That is why spans crossing February 29 count one extra day compared with a non-leap year.
Can it count only weekdays and skip weekends?
Yes. Tick the weekdays only option to split the span into working days (Monday to Friday) and weekend days (Saturday and Sunday); the two always add up to the total days. It does not subtract public holidays, so for that use a business-days calculator.

Related tools

Calculators guides

View all