Days, weeks and months between two dates, or a date plus or minus days, weeks or months
Runs in your browser. Nothing you type is sent anywhere. Updated on 25 Oct 2026.A date calculator counts the days, weeks and months between two dates, or finds the date a span away. From 15 January to 4 July 2026 is 170 days, 24 weeks and 2 days, or 5 months and 19 days; 90 days after 15 January 2026 is Wednesday 15 April.
Under Work out, choose Time between two dates, or Add or subtract to move a date forward or back.
Pick the From and To dates, or use From today and To today.
Turn on Include the end date if both days should be counted.
Choose how to Show the answer in: Days, Weeks, Months, or Years, months, days.
Read the result with weekdays and weekend days below it, then press Share result to copy a link.
The Date Calculator does two jobs. Between two dates gives the gap as total days, as weeks and days, as months and days, and as years, months and days, plus how many of those days are weekdays and how many are Saturdays and Sundays. Add or subtract takes a date and a span in years, months, weeks and days and gives the date it lands on, with its weekday.
Counting the end date. By default the count runs from the start date up to the end date, the way an age or a loan term is counted: 1 to 31 January is 30 days. Switch on "Include the end date" when both ends count, as for days of leave or a hotel booking counted in days rather than nights; the same dates then give 31 days.
How months are counted. A month is a calendar month with the same day number. When the later month is shorter, the date moves to its last day: 31 January plus one month is 28 February, or 29 February in a leap year. The months between two dates are the most whole months that fit by that rule, and the days are what is left, so the answer always adds back to the end date exactly. Under this rule 31 January to 28 February is one month.
Leap years and time zones. The calendar is the Gregorian one, with 29 February every fourth year except century years not divisible by 400 (2000 was a leap year; 2100 will not be). Dates are counted as whole days, so a daylight saving change or your time zone never adds or removes one. Any date from the year 1000 to 9999 works.
What the calculator does not do: it does not count business days or skip holidays (the Business Days Calculator does), it does not work with times of day or hours, and it does not convert between calendars such as the Hindu or Islamic calendar. Everything runs in your browser and nothing you enter is sent anywhere.
Count the days left in the first month, add every full month in between, then add the day number of the last date. From 15 January to 4 July 2026 that is 16 + 28 + 31 + 30 + 31 + 30 + 4 = 170 days. The calculator does the same count instantly and handles leap years.
By default the count runs from the start date up to the end date without counting the end date, so 1 to 31 January is 30 days. Switch on Include the end date when both days count, as with leave or a booking counted in days, and the answer becomes 31.
Under the calendar-month rule used here, 31 January plus one month is 28 February, or 29 February in a leap year, because February has no 31st. Some spreadsheet functions behave the same way; JavaScript's own date arithmetic would roll over to 3 March instead, which is why this calculator does not use it.
Divide the days between the dates by 7. The whole number is the full weeks and the remainder is the extra days: 170 days is 24 weeks and 2 days, or about 24.29 weeks. The calculator shows both forms so a school term, a pregnancy week or a sprint can be read either way.
Add the days month by month. From 15 January 2026, January has 16 days left and February 28, which makes 44; March adds 31 to reach 75; the remaining 15 days land on Wednesday 15 April 2026. Choose Add or subtract, enter 90 days and the date appears with its weekday.
Leap years follow the Gregorian rule: every fourth year, except century years not divisible by 400, so 2000 had 29 February and 2100 will not. Dates are counted as whole days in UTC, so a daylight saving change or a different time zone can never add or remove a day from the answer.
Formula only: no rates or limits are read from an official source.
Still stuck? Ask about Date Calculator and anybody who knows can answer. No account needed.
Same job, other tools: Butter Cups to Grams – Sticks, tablespoons and cups of butter in grams · Flour Cups to Grams – How many grams in a cup of all-purpose, bread or whole wheat flour · Inches to Feet Converter – Convert inches to feet and inches with fractions, decimal feet and centimeters.
Also works as: Date Difference Calculator · Days Between Dates.