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Date Difference Calculator

Counting the days between two dates sounds simple until you actually try it. Months have 28, 29, 30 or 31 days, leap years add an extra day, and weekends and public holidays keep getting in the way of a clean answer. That is why a project that feels like "about three months" can turn out to be 94 days, 13 weeks, 67 weekdays or only 62 business days, depending on how you count — and each of those numbers is the right answer to a different question. This free date difference calculator gives you all of them at once. Enter a start date and an end date, choose whether to exclude weekends and US federal holidays, and it shows the total days, the total weeks, the weekdays, the business days, and the difference in calendar months. It runs entirely in your browser, with nothing to install and no account to create. Use it to plan a holiday, count down to a wedding or a deadline, work out how long a project will really take, or check the length of a notice period.

How to Use This Calculator

1. Enter the start date and the end date using the date pickers. Either order works: if the end date is earlier, the dates are swapped.
2. Tick "Exclude weekends" if you only want working days counted, and "Exclude holidays" to also remove US federal holidays.
3. Tap Calculate. Read the total days first, then the weekdays and business days for planning work.
4. Check the holiday list below to see which holidays fall inside your dates, and remember that state holidays and company holidays are not included.

Understanding the Results

The headline figure, total days, is the number of days from the start date up to but not including the end date — the standard way of measuring a period. So from 1 January to 2 January is 1 day, and from 1 January 2026 to 7 November 2026 is 310 days. If you need to count both the first and the last day, for example when counting the days of a holiday that includes the day you leave and the day you return, add one: the inclusive count is shown as a separate row. Total weeks is simply the total days divided by seven, shown with the leftover days, because a period rarely lands on an exact number of weeks.

Weekdays are Monday to Friday, and weekend days are Saturday and Sunday. In the example period there are 222 weekdays and 88 weekend days, which adds up to the 310 total days. Business days go one step further and remove US federal holidays that fall on a weekday. The 2026 federal holidays are listed in the table below. Eight of those fall on a weekday inside the example period, so the business-day count is 222 − 8 = 214. The list is approximate: federal offices observe a holiday on the Friday before when it falls on a Saturday, and on the Monday after when it falls on a Sunday, and your employer or state may observe different days, so always confirm deadlines that depend on a holiday.

Calendar months are counted like age: full months first, then the remaining days. From 1 January to 7 November 2026 is 10 months and 6 days, because ten full months bring you to 1 November and six more days bring you to 7 November. That is often the most natural way to describe a long period, but for contracts and notice periods the exact day count is the one that matters, and that is why both are shown.

Worked Example

Example — 1 January 2026 to 7 November 2026: Subtract the dates: 7 November is the 311th day of 2026 and 1 January is the 1st, so the difference is 311 − 1 = 310 days. That is 310 ÷ 7 = 44 weeks and 2 days, or 311 days counting both dates. Counting Monday to Friday in that span gives 222 weekdays and 88 weekend days. Eight US federal holidays fall on a weekday in the span — New Year's Day, Martin Luther King Jr. Day, Presidents Day, Memorial Day, Juneteenth, Independence Day (observed), Labor Day and Columbus Day — so the business-day count is 222 − 8 = 214 business days. In calendar terms the period is 10 months and 6 days.

Example — a 90-day project starting 1 September 2026: Ninety days after 1 September is 30 November 2026. But if the team only works weekdays, those 90 calendar days contain about 64 weekdays, and after removing Labor Day, Columbus Day and Veterans Day, the real working time is closer to 60 business days.

Frequently Asked Questions

US Federal Holidays in 2026

This list is approximate and covers federal holidays only. State holidays, school holidays and company holidays are not included, and the observed date is used when a holiday falls on a weekend.