A date difference calculator counts the days between two dates and also shows the gap in weeks and in years, months and days. From 1 January 2026 to 21 October 2026 is 293 days, or 41 weeks and 6 days.
On this page
How to use the date difference calculator
- Enter the start date.
- Enter the end date.
- Read the total days, weeks and the years, months and days breakdown.
- Add 1 if you need to include both the start and end dates.
What formula does the date difference calculator use?
- Days between = end date − start date, counting the start date as day 0 (the end date is not added as an extra day)
- Weeks = days ÷ 7, with the remainder shown as days
- Years, months and days: count whole years, then whole months, then the days left over
- To include both the start and end dates, add 1 to the day count
Date difference calculator worked example
| Start | End | Days | Weeks | Years, months, days |
|---|---|---|---|---|
| 01 Jan 2026 | 21 Oct 2026 | 293 | 41 wk 6 d | 0 y 9 m 20 d |
| 01 Feb 2024 | 01 Mar 2024 | 29 | 4 wk 1 d | 0 y 1 m 0 d |
| 01 Feb 2025 | 01 Mar 2025 | 28 | 4 wk 0 d | 0 y 1 m 0 d |
| 15 Jun 2020 | 21 Oct 2026 | 2,319 | 331 wk 2 d | 6 y 4 m 6 d |
| 21 Oct 2026 | 25 Dec 2026 | 65 | 9 wk 2 d | 0 y 2 m 4 d |
From 1 January 2026 to 21 October 2026 is 293 days: 31 + 28 + 31 + 30 + 31 + 30 + 31 + 31 + 30 days for January to September, plus 20 days into October. 2026 is not a leap year, so February has 28 days.
Leap years in the date difference
Under the Gregorian calendar a year is a leap year if it divides by 4, except century years, which must divide by 400. So 2024 and 2028 are leap years, 2000 was, and 1900 and 2100 are not. The table shows the effect: 1 February to 1 March is 29 days in 2024 but 28 days in 2025.
Inclusive vs exclusive counting
The tool counts the gap between dates. If you are counting days on which something happens, such as a hotel stay counted by nights versus days, or a notice period that includes the first and last day, add 1. Contracts and legal deadlines often have their own counting rules, so check the wording; some exclude weekends or public holidays.
Why months are not a fixed length
Months have 28 to 31 days, so “one month” from 31 January has no matching day in February. Different tools resolve this differently, which is why a years-months-days answer can vary by a day between calculators while the total day count is always the same. If an exact figure matters, rely on the total days, which every date difference calculator should agree on.
Working days
The tool counts calendar days, including weekends and holidays. For a rough count of working days, multiply the weeks by 5 and add the weekdays in the remaining days, then subtract public holidays in the period.
Estimates for planning only. Check important figures with an official source or a qualified professional.
Common uses for a date difference
People use a date difference calculator for many everyday tasks: counting days until a holiday or deadline, checking how long a contract has run, working out notice periods, or tracking how long ago an event happened. Businesses use day counts for invoices, interest and warranties. For age calculations, the years, months and days breakdown is usually what you want, while for interest or penalties the total day count matters.
Before you rely on a day count for something official, check the counting rule. Some rules exclude the first day, some include the last, and some count only business days. Enter the dates in the date difference calculator, then add or subtract a day to match the rule you need.
Dates across time zones
Dates can shift across time zones: an event late in the evening in New York happens on the next calendar day in London. If two dates come from different places, convert them to one time zone first. The calculator counts whole calendar days, so the time of day does not affect the result.
Related converters and calculators
Related calculators:
- Time duration calculator: hours
- Age calculator: age
- Due date calculator: pregnancy
Sources
timeanddate.com: Leap year rules; NIST: A Walk Through Time (calendars).
Days between dates: quick answers
Pick two dates to see total days, then weeks and leftover days, plus a years-months-days breakdown. Common ranges: 7 days = 1 week; 14 days = 2 weeks; 30 days is not always one calendar month because months have 28 to 31 days.
Weeks between two dates
Weeks between = floor(total days ÷ 7), with the remainder shown as extra days. Example: 293 days = 41 weeks and 6 days.
Add or subtract days mode
Use the Mode menu to add days to a date or subtract days from a date, or keep Days between two dates for a gap count. Guide: how to add or subtract days from a date.
Questions about this calculator
How many days are there between two dates?
Subtract the start date from the end date; the tool does this and accounts for leap years.
Does the count include the end date?
No. Add 1 to include both the start and end dates.
How many days from 1 Jan to 21 Oct 2026?
293 days.
Are leap years included?
Yes. February has 29 days in leap years such as 2024 and 2028.
Does it count working days?
No, it counts calendar days including weekends and holidays.
Check the assumptions and units before relying on a result. Financial, tax and health estimates do not replace advice for your individual circumstances.
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