🗓️ Days Between Dates Calculator: Count Days, Weeks and Business Days
By Shihab Mia · Updated 2026-07-13
Enter a start date and an end date and this calculator instantly counts the exact number of days between them. It also shows the same span as weeks, business days, total hours, and a calendar-aware years, months, and days breakdown. The plain day count is exclusive, meaning it counts the gap between the two dates, so 13 July to 3 August 2026 is 21 days. If you need the end day counted too, use the "days including the end" figure, which is simply the total plus one.
What is the Days Between Dates Calculator?
Counting the days between two dates by hand is slow and error prone because months have different lengths and leap years add a day every four years. This calculator removes that guesswork. It reads each date as a plain calendar date, works out the gap in whole days, and then expresses that same gap in several units at once so you can pick whichever fits your task. Under the hood every date is handled in Coordinated Universal Time (UTC), which means daylight-saving clock changes never add or drop an hour and never push a result off by a day.
The headline number is the total days, an exclusive count. Exclusive means the start date is day zero and you count forward from there, so the number of nights between the dates. From 1 March to 8 March is 7 days, not 8. This is how banks count interest periods and how most contracts count notice periods. When a rule counts both the first and the last day, for example a hotel stay measured in nights versus a festival measured in days attended, you want the inclusive figure instead, which this tool shows separately as total days plus one.
The years, months, and days breakdown is calendar aware, not a rough division. It steps whole years first, then whole months, then leftover days, borrowing the correct number of days from the month before the end date when needed. That is why 15 January 2025 to 20 March 2026 reads as 1 year, 2 months, and 5 days rather than a flat 429 days divided by 30. Weeks are the total days divided by seven, hours are the total days multiplied by 24, and business days count only Monday to Friday within the span, so a 21-day span that starts on a Monday contains exactly 15 business days.
Leap years are handled automatically. A common year has 365 days and a leap year has 366, with the extra day being 29 February. A year is a leap year when it is divisible by 4, except century years, which must also be divisible by 400. So 1900 was not a leap year but 2000 was, and 2024 was. Because these rules are built in, a span that crosses one or more 29 February dates still returns the correct total. For example, all of 2020 measured from 1 January 2020 to 1 January 2021 is 366 days, while the same span in the non-leap year 2019 is 365 days.
When to use it
- Counting how many days are left until a deadline, launch, exam, wedding, or holiday.
- Measuring how long ago something happened, such as days since a purchase, a hire date, or a last payment.
- Working out business days for shipping estimates, service level agreements, or payment terms that exclude weekends.
- Calculating an age or a length of service as an exact number of years, months, and days.
- Checking a stay or rental in nights versus days, where inclusive and exclusive counting differ.
- Converting a date span into weeks or hours for timesheets, project planning, or medical dosing schedules.
How to use the Days Between Dates Calculator
- Enter the start date, or click Start = today to use the current date.
- Enter the end date, or click End = today.
- Read the total days, the inclusive count, weeks, business days, hours, and the years-months-days breakdown.
- Order does not matter: if the end is before the start, the tool uses the absolute difference. Use Swap dates to flip them.
- Click Copy result to copy the full plain-language summary to your clipboard.
Formula & method
Worked examples
How many days between 13 July 2026 and 3 August 2026?
- Read both dates as UTC calendar dates.
- The gap is 21 whole days (the rest of July after the 13th plus the first 3 days of August).
- Divide 21 by 7 to get 3.00 weeks; the span starts on a Monday, so it holds 15 business days.
- Add one for the inclusive count if you need the end day counted.
Result: Result: 21 days, or 22 days including the end, which is 3 weeks and 504 hours.
How many days between 1 January 2020 and 1 January 2021 (a leap year)?
- The year 2020 is divisible by 4 and is a leap year, so it contains 29 February.
- Count every calendar day from 1 January 2020 up to 1 January 2021.
- Because of the leap day, the total is 366 rather than 365.
- Expressed in calendar units this is exactly 1 year and 0 days.
Result: Result: 366 days, equal to 1 year, which is 52.29 weeks and 8,784 hours.
Common spans and their exact day counts
| Span | Total days | Weeks | Business days (approx.) |
|---|---|---|---|
| 1 week | 7 | 1.00 | 5 |
| 2 weeks (fortnight) | 14 | 2.00 | 10 |
| 3 weeks | 21 | 3.00 | 15 |
| 30 days | 30 | 4.29 | 21 to 22 |
| 60 days | 60 | 8.57 | 42 to 44 |
| 90 days | 90 | 12.86 | 63 to 66 |
| 1 common year | 365 | 52.14 | 260 to 262 |
| 1 leap year | 366 | 52.29 | 261 to 262 |
Days in each month (common year vs leap year)
| Month | Days (common year) | Days (leap year) |
|---|---|---|
| January | 31 | 31 |
| February | 28 | 29 |
| March | 31 | 31 |
| April | 30 | 30 |
| May | 31 | 31 |
| June | 30 | 30 |
| July | 31 | 31 |
| August | 31 | 31 |
| September | 30 | 30 |
| October | 31 | 31 |
| November | 30 | 30 |
| December | 31 | 31 |
Common mistakes to avoid
- Counting inclusively when you meant the gap. The plain total is exclusive: it counts the nights between the dates, so 1 March to 8 March is 7 days. If you need both the start and the end day counted, use the days-including-the-end figure, which adds one.
- Treating a month as exactly 30 days. Months range from 28 to 31 days, so 30 days is not one calendar month. The years-months-days breakdown steps real calendar months, which is why 31 January to 28 February reads as 28 days and not 1 month.
- Ignoring leap years. A span that crosses 29 February is one day longer than you might expect. A full year is 365 days in a common year but 366 in a leap year, so subtracting a fixed 365 can miss the correct date by a day.
- Mixing up calendar days and business days. Business days count only Monday to Friday, so a 30 calendar-day span is roughly six working weeks once weekends are removed. This tool counts weekends in the day total but reports business days separately, and it does not subtract public holidays.
Glossary
- Start date
- The earlier reference date you are counting from. If you enter it after the end date, the tool still uses the absolute difference.
- End date
- The later reference date you are counting to. The plain total does not include this day; the inclusive figure does.
- Exclusive count
- A day count that treats the start as day zero, so it measures the gap or number of nights between two dates.
- Inclusive count
- A day count that includes both the start and the end day, equal to the exclusive total plus one.
- Business day
- A weekday from Monday to Friday. Public holidays are not deducted by this calculator.
- Leap year
- A 366-day year containing 29 February. It occurs when the year is divisible by 4, except century years not divisible by 400.
Frequently asked questions
How many days are between two dates?
Enter the start and end dates and the calculator returns the exact number of whole days between them. The count is exclusive, so it measures the gap: from 1 March to 8 March is 7 days. Use the days-including-the-end figure if you need both endpoints counted.
Does the day count include the end date?
The main total is exclusive and does not count the end date, so it shows the number of nights between the two dates. The tool also shows a separate inclusive figure, which is the total plus one, for cases where both the first and last day should count.
How are business days calculated?
Business days are the Monday-to-Friday dates within the span, counted from the start date up to the end date. Weekends are excluded, so a 21-day span starting on a Monday contains 15 business days. Public holidays are not subtracted because they vary by country and region.
Does the calculator handle leap years?
Yes. Leap days are counted automatically, so a span crossing 29 February is one day longer. A full year is 365 days in a common year and 366 days in a leap year. For example, 1 January 2020 to 1 January 2021 is 366 days because 2020 is a leap year.
What if the end date is before the start date?
It still works. The calculator uses the absolute difference, so the order of the two dates does not change the result. You can also click Swap dates to flip them if you want the fields in chronological order.
Why does the time zone not affect the result?
Every date is handled as a plain calendar date in UTC, so daylight-saving clock changes never add or remove an hour and the day count is never pushed off by one. The date you enter and the date you count to are read as calendar days, not moments in time.