A days between dates calculator counts how many days lie between two dates, and also shows the answer in weeks, in years, months and days, and as working days. Pick a start date and an end date and the count appears at once, with an option to include the end date and the working shown.
Quick answer: days between two dates = end date minus start date. From October 8 to December 25, 2026 there are 78 days (79 if the end date is included), which is 11 weeks and 1 day, or 2 months and 17 days, with 56 working days.
How to use this days between dates calculator
- Pick the start date. It opens on today.
- Pick the end date. If it is earlier than the start, the days between dates calculator swaps them and tells you.
- Tick Include the end date only if both the first and the last day count (for example, a hotel stay that includes the checkout day or a leave request).
- Read the number of days, then the weeks, months, working days and the weekday table. Tap Copy result to paste the numbers.
| Result | What it shows | Example (Oct 8 to Dec 25, 2026) |
|---|---|---|
| Days | The count of days between the two dates | 78 days |
| Weeks and days | Days divided by 7 with the remainder | 11 weeks and 1 day |
| Years, months, days | Whole calendar months, then leftover days | 0 years, 2 months, 17 days |
| Working days | Monday to Friday only; holidays are not removed | 56 working days |
| Hours and minutes | Whole days times 24 and times 1,440 | 1,872 hours |
How many days between two dates: the formula
To find how many days between two dates, subtract the earlier date from the later one: days = end date − start date. Inside the days between dates calculator each date becomes a day number, a count of days from a fixed starting point, so the subtraction is exact across months and years, and leap years are handled correctly. Weeks are the days divided by 7. Hours are the days times 24.
Worked example 1: October 8 to December 25, 2026
- Days left in October after the 8th: 23 (to October 31). November has 30 days. December 1 to 25 adds 25.
- Add them: 23 + 30 + 25 = 78 days.
- Weeks: 78 ÷ 7 = 11 remainder 1, so 11 weeks and 1 day.
- Years, months, days: October 8 plus 2 months is December 8, and December 8 to December 25 is 17 days, so 2 months and 17 days.
- Working days: 78 days contain 11 full weeks (55 working days) plus 1 leftover day, a Thursday, making 56.
Worked example 2: all of 2026
January 1 to December 31, 2026 is 364 days with the end date left out, and 365 days with the end date included, which is every day of the year. It contains 52 full weeks plus 1 day, and 261 working days, because 2026 starts and ends on a Thursday.
Include the end date: when to add one day
The include end date option adds one day, because it counts both the first and the last date. Without it, the result counts the days that pass after the start date, so Monday to Friday is 4 days. With it, the same dates cover 5 days, which is how people usually count days of leave, days of a trip and days of a course.
| Situation | Include the end date? | Why |
|---|---|---|
| Days of annual leave from Mon to Fri | Yes | Both days are days off |
| Nights in a hotel | No | You pay for nights, not for the checkout day |
| Days until a deadline | Usually no | Today is not yet counted |
| Days between two birthdays or anniversaries | No | The usual elapsed time |
| Contract that says “inclusive of both dates” | Yes | The wording decides |
Working days between dates
Working days between dates are the Monday to Friday days in the range. The days between dates calculator counts each full week as 5 working days and checks the leftover days one by one. Public holidays are not removed, because they differ by country, state and employer; subtract them yourself, or use the business days calculator. Official holiday lists: the US federal holidays and UK bank holidays.
| Month | Days 2026 | Working days 2026 | Days 2027 | Working days 2027 |
|---|---|---|---|---|
| January | 31 | 22 | 31 | 21 |
| February | 28 | 20 | 28 | 20 |
| March | 31 | 22 | 31 | 23 |
| April | 30 | 22 | 30 | 22 |
| May | 31 | 21 | 31 | 21 |
| June | 30 | 22 | 30 | 22 |
| July | 31 | 23 | 31 | 22 |
| August | 31 | 21 | 31 | 22 |
| September | 30 | 22 | 30 | 22 |
| October | 31 | 22 | 31 | 21 |
| November | 30 | 21 | 30 | 22 |
| December | 31 | 23 | 31 | 23 |
| Whole year | 365 | 261 | 365 | 261 |
Weeks between two dates, and months and years
To get the weeks between two dates, divide the days by 7. The whole weeks are the quotient and the remainder is extra days. Months and years are harder because months vary from 28 to 31 days, so the days between dates calculator reports whole calendar months and leftover days, not a rough number. The decimal columns here use average lengths: 30.4369 days per month and 365.2425 days per year.
| Days | Weeks and days | Weeks (decimal) | Months (average) | Years (average) |
|---|---|---|---|---|
| 7 | 1 week | 1.00 | 0.23 | 0.019 |
| 14 | 2 weeks | 2.00 | 0.46 | 0.038 |
| 30 | 4 weeks and 2 days | 4.29 | 0.99 | 0.082 |
| 60 | 8 weeks and 4 days | 8.57 | 1.97 | 0.164 |
| 90 | 12 weeks and 6 days | 12.86 | 2.96 | 0.246 |
| 100 | 14 weeks and 2 days | 14.29 | 3.29 | 0.274 |
| 180 | 25 weeks and 5 days | 25.71 | 5.91 | 0.493 |
| 365 | 52 weeks and 1 day | 52.14 | 11.99 | 0.999 |
| 1,000 | 142 weeks and 6 days | 142.86 | 32.85 | 2.738 |
Days until a date from today
To find days until a date, use today as the start date and the target date as the end date. From October 8, 2026 these are popular targets. The result is the same whether you call it days until, days left or days remaining. For a countdown that always starts from today, use the days until calculator.
| Date | Calendar date | Weekday | Days from Oct 8, 2026 | Weeks and days |
|---|---|---|---|---|
| Halloween | Oct 31, 2026 | Saturday | 23 days | 3 weeks and 2 days |
| Thanksgiving (US) | Nov 26, 2026 | Thursday | 49 days | 7 weeks |
| Christmas Day | Dec 25, 2026 | Friday | 78 days | 11 weeks and 1 day |
| Last day of 2026 | Dec 31, 2026 | Thursday | 84 days | 12 weeks |
| New Year’s Day | Jan 1, 2027 | Friday | 85 days | 12 weeks and 1 day |
| Valentine’s Day | Feb 14, 2027 | Sunday | 129 days | 18 weeks and 3 days |
| Start of summer (June 21) | Jun 21, 2027 | Monday | 256 days | 36 weeks and 4 days |
Days between dates calculator: quick examples
These are the questions people type into a days between dates calculator most often, with the answers worked out from the same start date, October 8, 2026. Each one can be repeated in the tool by typing the two dates.
| Question | Days | Weeks and days |
|---|---|---|
| Days since January 1, 2026 | 280 days | 40 weeks |
| Days left in 2026 after October 8 | 84 days | 12 weeks |
| Days between Christmas 2026 and Christmas 2027 | 365 days | 52 weeks and 1 day |
| Days in the first quarter of 2027 (Jan 1 to Mar 31, both days counted) | 90 days | 12 weeks and 6 days |
| Days from Oct 8, 2026 to June 1, 2027 | 236 days | 33 weeks and 5 days |
| A 14-night stay checking in Oct 8, 2026 | 14 days | 2 weeks |
How the days between dates calculator handles month ends and leap years
The days between dates calculator never assumes that a month has 30 days. It turns each date into a day number from a fixed starting point, so February 28 to March 1 is 1 day in 2027 and 2 days in 2028.
The years, months and days line works differently: it adds whole calendar months to the start date, and if the day does not exist in a month, it uses that month’s last day. A start of January 31 plus 1 month is February 28 or 29, so January 31 to March 1 comes out as 1 month and 1 or 2 days. The total in days is always exact, whatever the month lengths.
Counting days for stays, leases and notices
Use the days between dates calculator for any limit expressed in days: how long a trip lasts, how many days remain on a lease or a notice period, how many days a warranty has left, or how long a project took. Each document sets its own rule for the first and last day, so read the wording and tick the include end date box if both days count. For visa and immigration stays, always follow the official counting rules of the country concerned, because they can differ from a simple count.
Days in a year, a month and a leap year
A common year has 365 days and a leap year has 366, because February gains a 29th day. A year is a leap year when it divides by 4, except century years, which must divide by 400 (see leap year). That is why 2000 was a leap year and 2100 will not be.
| Year | Leap year? | Days in the year | Rule |
|---|---|---|---|
| 2024 | Yes | 366 | Divisible by 4 |
| 2026 | No | 365 | Not divisible by 4 |
| 2028 | Yes | 366 | Divisible by 4 |
| 2100 | No | 365 | Divisible by 100 but not by 400 |
| 2000 | Yes | 366 | Divisible by 400 |
Days from January 1 to the first of each month
These numbers let you do the subtraction in your head: find the day of the year of each date and subtract. Day of the year = days elapsed to the first of the month + the day of the month, plus 1 for dates after February in a leap year.
| Month | Days in month | Days elapsed before the 1st (common year) | Days elapsed before the 1st (leap year) |
|---|---|---|---|
| January | 31 | 0 | 0 |
| February | 28 (29 in leap years) | 31 | 31 |
| March | 31 | 59 | 60 |
| April | 30 | 90 | 91 |
| May | 31 | 120 | 121 |
| June | 30 | 151 | 152 |
| July | 31 | 181 | 182 |
| August | 31 | 212 | 213 |
| September | 30 | 243 | 244 |
| October | 31 | 273 | 274 |
| November | 30 | 304 | 305 |
| December | 31 | 334 | 335 |
Example: February 28 to March 1 is 1 day in 2027 but 2 days in 2028, because 2028 has a February 29.
Days between dates in Excel, Google Sheets, SQL and code
Spreadsheets and programs store dates as numbers, so the subtraction works anywhere. These are the standard ways, with the start date in A1 and the end date in B1 for spreadsheets.
| Tool | Formula | Notes |
|---|---|---|
| Excel | =B1-A1 | Also =DAYS(B1,A1) and =DATEDIF(A1,B1,”d”) |
| Google Sheets | =B1-A1 | Also =DAYS(B1,A1) |
| Working days (Excel, Sheets) | =NETWORKDAYS(A1,B1) | Counts both end dates; add a holiday list as a third argument |
| Python | (date2 – date1).days | With datetime.date objects |
| JavaScript | (Date.UTC(y2,m2-1,d2) – Date.UTC(y1,m1-1,d1)) / 86400000 | UTC avoids daylight saving shifts |
| SQL (MySQL) | DATEDIFF(end_date, start_date) | SQL Server: DATEDIFF(day, start_date, end_date) |
Be careful with programs that subtract timestamps and divide by 86,400,000 milliseconds: a daylight saving change makes some days 23 or 25 hours, which can give an answer off by one unless you use UTC or whole dates. Finance has its own rules too, called day count conventions, such as actual/365 or 30/360 for interest.
Common mistakes when counting days between dates
- Off by one. Decide first whether the end date counts. The answer changes by 1.
- Using 30 days for every month. Months have 28 to 31 days, so the real count differs.
- Mixing date formats. 05/06/2026 is May 6 in the US and June 5 in most other countries.
- Forgetting that working days skip weekends. 90 days is not 90 working days; it is about 64.
- Ignoring holidays. Subtract public holidays that fall on weekdays if you need exact working days.
Real-life uses for a days between dates calculator
A days between dates calculator is one of the most used date tools, because so many decisions are phrased in days.
- Leave and travel: days of a trip, a stay limit or a notice period.
- Projects and school: days to a deadline, weeks in a term, days left in the semester.
- Money: days between invoice and payment, days of interest, days in a billing period.
- Health and family: days since or until an event; use the age calculator for exact age in days.
- Planning: add a number of days to a date with the date calculator.
Frequently asked questions
9 quick answers
How many days are there between two dates?
Subtract the earlier date from the later date. From October 8 to December 25, 2026 there are 78 days, or 79 if you count both the first and the last day.
How do I calculate the number of days between dates by hand?
Count the days left in the start month, add the days of each full month in between, then add the day number of the end date. For October 8 to December 25 that is 23 + 30 + 25 = 78.
Does the days between dates calculator include the end date?
Not by default. It counts the days that pass after the start date. Tick Include the end date to add one day, so that both the first and the last day are counted.
How many working days are between two dates?
Count the Monday to Friday days. Each full week has 5, and the leftover days are checked one by one. October 8 to December 25, 2026 has 56 working days. Public holidays are not removed.
How many days are in a year?
A common year has 365 days and a leap year has 366. 2026 has 365 days and 2028 has 366.
How many weeks between two dates?
Divide the days by 7. Seventy-eight days is 11 weeks and 1 day. The days between dates calculator shows weeks and days and the decimal number of weeks.
How do I calculate days between dates in Excel?
Type the end date in B1 and the start date in A1, then use =B1-A1 or =DAYS(B1,A1). For working days use =NETWORKDAYS(A1,B1).
How many days until a date from today?
Leave today as the start date, pick the target date as the end date and read the days. Use the days until calculator for a countdown that always starts from today.
How many months are between two dates?
Count whole calendar months from the start date, then the leftover days. October 8 to December 25 is 2 months and 17 days. The days between dates calculator also shows the average-month decimal.
Related calculators
- Date calculator: add or subtract days, weeks, months and years
- Days until calculator: a countdown to any date
- Business days calculator: working days with holidays
- Age calculator: exact age in years, months and days
- Time calculator: add and subtract hours and minutes
- Printable calendars and the full calculator list
Sources and further reading
- Leap year (Wikipedia)
- Gregorian calendar (Wikipedia)
- Federal holidays (US Office of Personnel Management)
- UK bank holidays (gov.uk)
Last updated: October 2026.