By the Age-Finder team · Last updated 7 November 2026
Quick answer
Measure the gap between 1 January and 31 December 2026: 364 days, exactly 52 weeks. Enter a start date and an end date, and the calculator counts the days between them, in years, months and days, in weeks and in hours.
The Days Between Dates calculator counts the exact number of days from one date to another, and also shows the same span in calendar terms: years, months and days. Tick one box to include the end date in the count.
How to Use the Days Between Dates Calculator
Pick the start date: set the day and month, then type the year. Enter the end date the same way. The order does not matter; if the end date comes first, the calculator swaps them. Tick “Include the end date” if you want to count both the first and the last day.
Select Calculate to see the number of days, the calendar breakdown, and the span in weeks, months and hours. To count down from today to a future date, the Countdown Calculator shows the days until it. To find the date a number of days after a start date, use the Date Calculator.
How the Count Works
The calculator counts the number of days you move forward to get from the start date to the end date. From 1 January to 2 January is 1 day. This is the standard way to count the days between two dates, and it is how spreadsheets subtract one date from another.
One wording on the result line is wrong, and it is worth knowing about. The line reads “not counting the end date”, but the count includes the end date and excludes the start date.
From 1 January to 5 January the tool counts 4 days: 2, 3, 4 and 5 January. The start date is day zero; the end date is the last day counted. The wording will be corrected in the tool; the number it shows is already right.
Including the end date
Sometimes you need to count both the first and the last day, for example the number of days in a booking or an event that runs from Monday to Friday. Ticking “Include the end date” adds one day: 1 January to 2 January then counts as 2 days.
| Start | End | Days between | Counting both days |
|---|---|---|---|
| 1 January 2026 | 31 December 2026 | 364 | 365 |
| 29 February 2024 | 28 February 2025 | 365 | 366 |
| 1 January 2000 | 1 January 2026 | 9,497 | 9,498 |
| 14 May 1990 | 3 September 1995 | 1,938 | 1,939 |
Total Days or Months and Days?
The calculator shows two answers because both are useful, and they cannot be converted into each other with a fixed formula. The total in days is exact and unambiguous. The calendar breakdown counts completed years, then completed months, then the days left over.
Months have different lengths, so the same number of days can be a different number of months: 1 February to 1 March 2026 is 28 days and exactly 1 month.
1 March to 1 April 2026 is 31 days and also exactly 1 month. That is why dividing a day count by 30 or 30.44 only ever gives an approximate number of months. When a precise month count matters, use the calendar breakdown.
Month-end dates
When the start date is the 29th, 30th or 31st, a month is completed on the last day of a shorter month. From 31 January to 28 February 2026 is 28 days and counts as 1 month.
The same rule applies to 29 February start dates in common years: 29 February 2024 to 28 February 2025 is exactly 1 year. This is the rule used across Age-Finder and explained on the methodology page.
Leap Years and Long Spans
Every leap day between the two dates is included automatically. A leap year holds 366 days, with 29 February as the extra day. The rule is that a year ending in 00 is a leap year only when it divides by 400, while any other year is a leap year when it divides by 4.
That is why 2000 was a leap year and 2100 will not be. Over long spans this adds up: from 1 January 2000 to 1 January 2026 is 26 years but 9,497 days, because seven leap days fall in that period (2000, 2004, 2008, 2012, 2016, 2020 and 2024).
Days, Weeks and Hours
The result also shows the span in weeks and days, in completed months and in hours. Weeks are counted as whole 7-day blocks with any days left over: 364 days is exactly 52 weeks, while 365 days is 52 weeks and 1 day.
Hours are the number of days multiplied by 24. They are useful for very short spans and for comparing against rules written in hours. The calculator works with whole calendar dates, so it does not adjust for the hour lost or gained when clocks change for daylight saving time.
Business Days, Worked by Hand
The calculator counts every calendar day. It has no business-day count. When a deadline is written in working days, work them out by hand or use the Business Days Calculator.
The business-day figure below counts Monday to Friday, with the start date excluded and the end date included, the same convention as the calendar-day count on this page. A spreadsheet’s NETWORKDAYS counts both ends, which gives one more when both dates are weekdays.
| Start | End | Calendar days | Business days |
|---|---|---|---|
| 1 January 2026 | 31 December 2026 | 364 | 260 |
| 1 October 2026 | 25 December 2026 | 85 | 61 |
| 8 October 2026 | 25 December 2026 | 78 | 56 |
| 1 January 2026 | 1 April 2026 | 90 | 64 |
| 7 November 2026 | 5 February 2027 | 90 | 65 |
The first row shows why the convention matters: 1 January and 31 December 2026 are both Thursdays, so counting both ends gives 261 weekdays, one more than the 260 in the table. The last row shows the opposite: 7 November 2026 is a Saturday, so excluding the start changes nothing and both conventions give 65.
In Excel and Google Sheets
Put the earlier date in A1 and the later date in B1:
| What you want | Formula | Notes |
|---|---|---|
| Days between (exclusive) | =B1-A1 |
The standard count, the same as this calculator. |
| Days between (inclusive) | =B1-A1+1 |
Counts both the first and the last day. |
| Days between, direct | =DAYS(B1,A1) |
End minus start, the same as =B1-A1. |
| Complete days | =DATEDIF(A1,B1,"d") |
The same exclusive day count. |
| Complete months | =DATEDIF(A1,B1,"m") |
Whole months only, month-end rule applied. |
| Complete years | =DATEDIF(A1,B1,"y") |
Whole years only. |
| Business days | =NETWORKDAYS(A1,B1) |
Counts both ends, Monday to Friday only. |
| Business days, minus holidays | =NETWORKDAYS(A1,B1,C1:C5) |
List the holidays in C1:C5. |
Common Uses
Counting the days until or since an event, a project start or a deadline. Working out the length of a stay, a booking or a contract in days.
Checking how many days you have been in a job, a city or a relationship. Finding the number of days between two birthdays. For two people’s ages, the Age Difference Calculator also shows who is older.
What other days between dates calculators offer
Most days between dates calculators on the first page return the same number this one does. What sets them apart is whether they count business days and whether they offer an inclusive mode. The comparison below is against the three days between dates calculators that rank highest.
| Feature | Age-Finder | calxy | thetoolskit | scholarlytoolkit |
|---|---|---|---|---|
| Days between two dates | Yes | Yes | Yes | Yes |
| Inclusive mode (count both ends) | Yes, a checkbox | Yes | Yes | Yes |
| Years, months and days breakdown | Yes | Yes | Not shown | Yes |
| Weeks and hours shown | Yes | Yes | Yes | Yes |
| Business-day count | No, in the guide | Yes | Yes | Yes |
| Skip public holidays in business days | No | Yes, US federal | Not shown | Not shown |
| Add or subtract mode in the same tool | No | Yes | Yes | Not shown |
| Quick ranges | No | Not shown | Not shown | Yes, Today to +1 year |
| Free, no download or account | Yes | Yes | Yes | Yes |
What the tool still lacks: no business-day count, it cannot skip public holidays, it has no add or subtract mode, and it offers no quick ranges for common spans. What it adds is the years, months and days breakdown with the month-end rule stated, and the business days worked through by hand in the guide.
Frequently Asked Questions
Does the count include the start date and the end date?
By default the calculator counts the days you move forward, so the start date is not counted and the end date is. Tick “Include the end date” to count both days, which adds one.
Why does a month sometimes have 28 days and sometimes 31?
Calendar months have different lengths: February has 28 days (29 in a leap year), and other months have 30 or 31. A one-month span therefore covers 28 to 31 days depending on where it starts.
Can I enter the later date first?
Yes. If the end date is before the start date, the calculator swaps them and tells you. The number of days is the same either way.
Are leap days counted?
Yes. Every 29 February between the two dates is included in the total.
How many days are in a year?
A common year has 365 days and a leap year has 366. From a date to the same date one year later is therefore 365 or 366 days, depending on whether a 29 February falls in between.
How do I find the number of weeks between two dates?
Enter both dates and look at Weeks and days in the result. It shows the number of complete 7-day weeks and the days left over. For example, 1 January to 31 December 2026 is 364 days, which is exactly 52 weeks.
Does the calculator count only working days?
No, it counts every calendar day. Working-day counts exclude weekends and public holidays, which differ by country.
Sources
- The U.S. Naval Observatory leap years page is the source for the leap-year rule on this page.
- The U.S. Naval Observatory Julian Date Converter counts days continuously across months and years, the same idea as the day count on this page.
- Age-Finder methodology (how the month-end rule works on every calculator).