Days Between Dates Calculator

What the days between dates calculator does

The days between dates calculator tells you exactly how much time separates two dates. Pick a start date and an end date, and you get the total number of days at once — plus the same span expressed as weeks, and as a precise breakdown of years, months and days. It’s the fastest way to answer “how many days are there between two dates?” without counting on a calendar or fighting with a spreadsheet.

The tool goes further than a plain count. It can:

• show the gap in calendar days, in weeks, and as an exact years / months / days split;
• count business days only, skipping weekends (you choose which days count as the weekend);
• add or subtract any number of days from a date, optionally skipping weekends, to find a future or past deadline.

It works with any dates in the Gregorian calendar — past, future, across month ends, year ends and centuries — and it handles leap years automatically. Because the maths runs on plain calendar dates, there are no time-zone or daylight-saving surprises.

How to use it

1. Enter the start date. Any date you like — a signing date, a birthday, the first day of a trip.
2. Enter the end date. The calculator shows the total days between the two instantly. If you put the later date first, it quietly swaps them and shows the absolute gap, so the order never trips you up.
3. Open the advanced options if you need them. There you can include the end day in the count, switch the weekend pattern, or flip to add/subtract mode to shift a date forward or backward by a set number of days.

By default the end day is not counted — the result is the number of full days from the start up to (but not including) the end, which is the usual meaning of “days between.” Tick Include the end day when you want both ends counted, the way a booking or a legal term often works.

How the days between dates calculator works

At its core the calculation is a subtraction. The calculator converts each date to a day number on the calendar and subtracts one from the other:

Total days = end date − start date

Everything else is derived from that single, exact day count. Weeks are the total divided by seven: weeks = total days ÷ 7, with the remainder shown as leftover days. The years/months/days breakdown is worked out the calendar way — walking month by month and year by year using the real length of each month — not by dividing by an average of 365.25 days. That means the split lines up with how people actually read a calendar.

Leap years are baked in. February has 29 days in a leap year and 28 otherwise, and the calculator uses the real length every time. For example, February 2028 spans 29 days, while February 2026 spans 28 days.

Step-by-step example

Take 15 January 2026 to 10 July 2026, with the end day not counted.

1. Count the whole days from the start up to the end: that’s 176 days.
2. Express it in weeks: 176 ÷ 7 = 25 weeks and 1 day.
3. Express it as a calendar breakdown: 0 years, 5 months and 25 days.

All three describe the same span — 176 days is just seen through three different lenses. If you switch on Include the end day, the total becomes 177 days, which is 25 weeks and 2 days, or 5 months and 26 days.

Business days, weekends and the three weekend patterns

Alongside calendar days, the calculator counts business days — the days left once weekends are removed. This is the answer to “how many working days are there between two dates?”, the version that matters for delivery times, payment terms and deadlines.

You can choose what counts as the weekend, because it isn’t the same everywhere:

• Saturday + Sunday — the default, used across most of the world.
• Friday + Saturday — common in much of the Middle East.
• Sunday only — for a six-day working week.

Example. From Monday 6 July 2026 to Monday 13 July 2026, with the end day included, that’s 8 calendar days. One weekend falls inside the span — Saturday the 11th and Sunday the 12th — so there are 2 weekend days and 6 business days. Shorten it to Monday 6 July through Friday 10 July and you get a clean 5 business days, a full working week.

One important limit — read this. Business-day mode removes weekends only. It does not subtract public holidays, because holidays differ by country, region and year, and this calculator is global. So the business-day figure is “days that aren’t weekends,” not “days the office is open.” If a national holiday falls inside your range, subtract it yourself. A country-aware holiday option may come later, but today the tool is honest about counting weekends alone.

Adding and subtracting days from a date

Switch to add/subtract mode when you don’t have an end date but a number of days — “what date is 30 days from now?” or “which day was 10 days ago?” Enter a start date, choose add or subtract, and type the number of days.

• Add across a month end: 28 February 2026 plus 1 day lands on 1 March 2026. In a leap year it’s different — 28 February 2028 plus 1 day is 29 February 2028.
• Subtract across a year end: 5 January 2026 minus 10 days goes back to 26 December 2025.

There’s also a skip weekends option that counts only business days as it moves. Adding 1 business day to Friday 10 July 2026 skips the weekend and lands on Monday 13 July 2026. In this mode the weekend is fixed to Saturday and Sunday.

This kind of date arithmetic underpins plenty of everyday questions — a notice period, a return-by date, a project milestone, the running total of days on a visa or a 90-days-in-180 travel window, or someone’s exact age in years, months and days. Those specific cases each have their own rules, but they all start from the same building block: shifting a date by a known number of days.