Date Calculator

How to Calculate Days Between Dates

To find the number of days between two dates, subtract the earlier date from the later date. This calculator handles all the complexity of varying month lengths, leap years, and crossing year boundaries. Simply enter your start and end dates and get an instant result showing total days, weeks and remaining days, and months and remaining days.

For example, the number of days from January 1 to July 1 in a non-leap year is 181 days (25 weeks and 6 days). In a leap year, it is 182 days because February has 29 days instead of 28.

How to Calculate Days Between Two Dates

If you want to know exactly how many days from date to date, this date calculator between two dates does the math automatically. Pick a start date with the first date picker and an end date with the second one. The tool counts every calendar day between them and updates the result in real time, so you can experiment with different ranges without reloading the page.

The same workflow answers questions like how many days is from date to date, how many days between two dates, and how many weeks between two dates. Because everything runs in your browser, there is no waiting on a server and no data sent over the network — it is essentially an instant online datediff tool.

Business Days vs Calendar Days

Calendar days count every day including weekends and holidays. Business days (or working days) typically exclude Saturdays, Sundays, and public holidays. This calculator counts calendar days. As a rough guide, multiply calendar days by 5/7 to estimate business days, though this does not account for holidays.

For example, 30 calendar days is approximately 21–22 business days. A 90-day deadline is roughly 64 business days.

The distinction matters depending on what you are tracking. Legal notice periods, contract deadlines, and SLAs are usually expressed in business days, while age, anniversaries, vacation length, and historical date counts are almost always measured in calendar days. If your contract says "10 business days," count Monday through Friday only and skip any public holiday in your jurisdiction; if it says "10 days" without qualification, the default in most regions is calendar days.

This datediff calculator always reports the calendar-day total so you have a precise baseline. From there you can convert to business days yourself, or simply use the result as your date count for billing, age verification, deadline tracking, or any other purpose.

Common Use Cases

Deadlines: Calculate how many days until a project is due, or find the exact date N days from now.
Countdowns: Find out how many days until a holiday, birthday, wedding, or other event.
Age and duration: Calculate the exact number of days between two life events.
Legal and financial: Many contracts, leases, and financial instruments reference specific day counts (30-day notice, 90-day warranty, 365-day return policy).

Days Between Common Date Pairs (2026)

Frequently Asked Questions

How many days are between two dates?

Enter both dates into this calculator to find the exact number of calendar days. For example, from January 1 to March 1 in a non-leap year is 59 days.

How many days until the year ends?

Enter today's date as the start date and December 31 of the current year as the end date. The calculator shows exactly how many calendar days remain in the year, plus weeks and months.

How many days are in each month of 2026?

January: 31, February: 28 (2026 is not a leap year), March: 31, April: 30, May: 31, June: 30, July: 31, August: 31, September: 30, October: 31, November: 30, December: 31. Total: 365 days.

What date is 90 days from today?

Use the Add / Subtract Days tab. Select today's date, enter 90, and choose Add. The result shows the exact date 90 days from now, the day of the week, and the breakdown in weeks.

How do I add or subtract days from a date?

Use the Add / Subtract Days tab. Pick a starting date, enter the number of days, select Add or Subtract, and get the resulting date instantly.

How do I calculate the number of days between two dates?

Pick a start date and an end date in the calculator above. The tool counts every calendar day between the two dates and shows the result instantly, along with the equivalent in weeks, months, and years.

What is the difference between calendar days and business days?

Calendar days include every day of the week, including Saturdays, Sundays, and public holidays. Business days (or working days) only count Monday through Friday and exclude public holidays. This date to date calculator counts calendar days; multiply by 5/7 to estimate business days.

How many weeks are between two dates?

The calculator reports the number of full weeks plus any leftover days alongside the total day count. For example, 100 days equals 14 weeks and 2 days.

Can I calculate dates across different years?

Yes. The date calculator works across any year range and automatically accounts for leap years and varying month lengths. You can calculate the days between dates that span multiple decades.

What is a datediff calculator?

A datediff calculator (date difference calculator) computes how many days, weeks, months, or years separate two dates. The name comes from the DATEDIFF function found in SQL and spreadsheets. This online datediff tool gives you the same answer instantly, with no formula to write.