How to use the date difference calculator
- Choose what you want to know. Difference between two dates compares any start and end date. Days from today until a date counts the days left to a deadline, trip, birthday or exam, using today's date on your device as the start.
- Pick the dates with the date fields. On a phone, the built-in calendar opens; on a computer, you can type the month, day and year or use the arrow keys.
- Decide whether to count both ends. By default the start day is not counted and the end day is, which is how most people count "days between". Tick the inclusive box when both the first and last day count, such as a hotel stay or a leave request.
- Tick Also count business days if you need working days, and optionally subtract US federal holidays. Then press Calculate.
Calculate the number of days between two dates
Whether you are counting down to a wedding, working out how long a contract has run or checking how many days remain before a visa expires, the question is always the same: how far apart are these two dates? The answer sounds easy, but months have different lengths, leap years add a day in February and people disagree about whether to count the first day. This calculator does the careful bookkeeping for you and shows the result in several forms at once: total days, weeks and days, years-months-days and total hours.
Everything is computed in your browser from the calendar dates you pick. There are no clock times or time zones involved, so a daylight saving change cannot add or remove a day from your result. Nothing you enter is sent to a server.
How the result is calculated
Each date is converted into a day number, the count of days since January 1, 1970. The difference between the two numbers is the number of days. For the "years, months and days" breakdown, the tool first adds whole months to the start date for as long as the result does not pass the end date, then counts the days left over. When the start day does not exist in a later month, for instance January 31 plus one month, the date is clamped to the last day of that month, February 28 or 29. This is the same convention that most spreadsheets and legal calculations follow.
| Start | End | Days | Years, months, days |
|---|---|---|---|
| Jan 1, 2026 | Dec 31, 2026 | 364 (365 inclusive) | 0 years, 11 months, 30 days |
| Feb 28, 2024 | Mar 1, 2024 | 2 (leap year) | 0 years, 0 months, 2 days |
| Feb 28, 2025 | Mar 1, 2025 | 1 | 0 years, 0 months, 1 day |
| Jul 4, 2025 | Jul 4, 2026 | 365 | 1 year, 0 months, 0 days |
Inclusive or exclusive counting
If you ask how many days there are from Monday to Friday, most people say four: Tuesday, Wednesday, Thursday and Friday. That is exclusive counting of the start day. Hotels count nights the same way, so a check-in on the 10th and check-out on the 14th is four nights. Others say five, because they count Monday itself as a day of the week, and that is inclusive counting. Rental agreements, leave requests, project plans and court deadlines can use either approach, so always confirm which one the document uses. Tick or untick the inclusive box and the tool recalculates all figures accordingly.
Business days and federal holidays
Switch on Also count business days to see how many Monday-to-Friday days fall in your range and how many weekend days are left out. Many deadlines are expressed in business days, such as "payment within 10 business days" or "allow 3 to 5 business days for delivery". When you tick the holiday option, the tool also removes the US federal holidays that land on weekdays: New Year's Day, Martin Luther King Jr. Day, Presidents' Day, Memorial Day, Juneteenth, Independence Day, Labor Day, Columbus Day, Veterans Day, Thanksgiving Day and Christmas Day.
The dates of floating holidays are calculated for any year from the rule, for example the third Monday of January or the fourth Thursday of November. When a fixed-date holiday falls on a Saturday, the federal government observes it on the preceding Friday; when it falls on a Sunday, the observed day is the following Monday. The calculator follows that convention. Keep in mind that banks, courts, states, schools and employers publish their own calendars. The Federal Reserve, for instance, does not observe a Saturday holiday on Friday, and many companies give extra days off. Treat the business-day figure as a solid estimate and confirm exact dates with the organization that sets your deadline. Dates outside the United States, such as UK bank holidays, are not deducted.
Everyday uses
- Countdowns: days until a wedding, graduation, holiday, tax filing deadline or product launch. Choose "Days from today" and enter the target date.
- Work and legal deadlines: how many days remain in a 30-day notice period, a return window or a statute of limitations check. Always verify the official counting rule.
- Project planning: business days between a kick-off and a milestone, excluding weekends and holidays.
- Travel: length of a trip, nights at a hotel, or days until a passport or visa expires. Many countries require a passport to be valid for six months beyond your stay.
- Personal milestones: days since you quit a habit, started a job or moved to a new city, and how long until the next anniversary.
- Pregnancy and health tracking: days between appointments or since a start date. This tool does not give medical advice, and due dates should always come from your clinician.
Common date-counting mistakes
The most frequent error is forgetting that February has 29 days in a leap year. A year is a leap year when it is divisible by 4, except for century years that are not divisible by 400, so 2024 and 2028 are leap years, 1900 and 2100 are not, and 2000 was. Another trap is month arithmetic: "one month after January 31" has no obvious answer, which is why this tool shows the difference both as total days and as years, months and days. A third pitfall is mixing date formats. In the United States dates are written month/day/year, while most of the world writes day/month/year, so 04/05/2026 means April 5 in New York and May 4 in London. The date picker avoids ambiguity because it displays and stores the date in a fixed way, and the result text spells out the month name.
When you copy a result into an email or contract, include both dates and say whether the first day is counted. That one sentence prevents most disputes about a deadline.
Limits
The calculator accepts dates from 1900 to 2100 and uses the Gregorian calendar throughout. Results are for planning and information. They are not legal advice, and for official deadlines such as court filings or tax returns you should rely on the rules of the relevant authority.
Private by design
The dates you enter are processed entirely in your browser tab. Nothing is uploaded or stored, there is no account, and the page keeps working offline after it has loaded.
Frequently asked questions
How do I calculate the number of days between two dates?
Pick a start date and an end date and press Calculate. The tool converts both dates to day numbers and subtracts them, giving the exact number of days, including leap days. By default the start day is not counted and the end day is; tick the inclusive box to count both.
What is the difference between inclusive and exclusive counting?
Exclusive counting leaves out the first day, so Monday to Friday is 4 days. Inclusive counting includes both ends, so the same range is 5 days. Hotel nights follow the exclusive method, while leave requests and event durations often use the inclusive one. Check which rule your document uses.
How are business days counted?
Business days are Monday to Friday within your range. Saturdays and Sundays are excluded, and if you tick the holiday option, US federal holidays that fall on weekdays are removed as well. Company, state and school holidays are not included, so adjust manually if they apply.
Which US federal holidays are deducted, and how are observed dates handled?
The tool deducts New Year's Day, MLK Day, Presidents' Day, Memorial Day, Juneteenth, Independence Day, Labor Day, Columbus Day, Veterans Day, Thanksgiving and Christmas. A holiday on a Saturday is observed on Friday and one on a Sunday is observed on Monday. The dates work for any year in the supported range.
Does the calculator handle leap years?
Yes. Leap years follow the Gregorian rule: years divisible by 4 are leap years, except century years not divisible by 400. For example, there are 366 days from March 1, 2024 to March 1, 2025, because February 29, 2024 is in between, but only 365 days the following year.
Why does the years-months-days result differ from the total days?
Months have between 28 and 31 days, so a month is not a fixed number of days. The years-months-days breakdown counts whole calendar months first and then the leftover days, while total days is the plain count. Both are correct; they just answer different questions.
Can I find how many days are left until a future date, like a deadline?
Yes. Switch to "Days from today until a date" and enter the target. The tool uses today's date from your device's clock, so the answer changes every day. If the target is in the past, it tells you how many days ago it was.
Are my dates stored or sent anywhere?
No. All calculations happen in your browser, nothing is uploaded and no account is needed. The tool is free with no limit on how often you use it.
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