Date Calculator
Date calculator: days between two dates in years, months and days, with weekdays and business days counted. Free, no sign-up, and it runs in your browser.
Dedicated page: /en/date-calculator
2026 list, checked 10 Nov 2026 against OPM. Check the current value here.
Independence Day falls on Saturday, 4 July 2026, and is observed on Friday, 3 July. Only one of the two dates is counted as a holiday.
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Quick answer
A date calculator finds the time between two dates. From 1 January 2026 to 25 December 2026 is 358 calendar days, or 11 months and 24 days, or 51 weeks and 1 day. It also counts weekdays, weekend days and business days, with the 2026 US federal holidays built in.
About this Date Calculator
Date calculator: days between two dates in years, months and days, with weekdays and business days counted. It is one of the Work and School on ToolUstad, and like every tool here it runs entirely in your browser: nothing you type, paste or open is uploaded to a server, and there is no sign-up or usage limit.
What is a date calculator?
A date calculator does the calendar arithmetic people get wrong by hand: how many days are there between two dates, what date is 100 days from now, and what day of the week was a date? The answers look simple, but months have different lengths, February changes in leap years, and weekends and holidays have to be counted separately. From 1 January 2026 to 25 December 2026 is 358 calendar days: 11 months and 24 days, or 51 weeks and 1 day. Of those, 256 are weekdays and 102 are weekend days, and with the 10 US federal holidays inside the span subtracted, business days are 246.
The calculator has three modes. Add or subtract from a date takes a start date and a number of days, weeks, months or years, and gives the resulting date and its weekday. The weekday mode takes a single date and gives the day of the week, whether the year is a leap year, and the Monday and Sunday of the same week.
Calendar days, weekdays and business days
Three counts describe the same span, and they answer different questions. Calendar days count every day, including weekends and holidays: that is the number for countdowns, pregnancies, and ages. Weekdays count Monday to Friday, and weekend days count Saturday and Sunday. Business days count Monday to Friday minus public holidays, and that is the number for project deadlines, delivery dates and notice periods. The calculator counts business days by stepping through the span day by day, skipping Saturdays and Sundays, and skipping US federal holidays when the holiday option is on. State holidays, bank holidays and school calendars vary, so they are not included: the list is the federal list only.
US federal holidays 2026
The 2026 list is built in, checked 10 November 2026 against the Office of Personnel Management schedule. There are 11 federal holidays: New Year's Day on Thursday 1 January, Martin Luther King Jr. Day on Monday 19 January, Washington's Birthday on Monday 16 February, Memorial Day on Monday 25 May, Juneteenth on Friday 19 June, Independence Day on Saturday 4 July, Labor Day on Monday 7 September, Columbus Day on Monday 12 October, Veterans Day on Wednesday 11 November, Thanksgiving Day on Thursday 26 November, and Christmas Day on Friday 25 December.
Best practices
- Decide the end-day rule before you quote a deadline: between-count and inclusive-count differ by exactly one day, and contracts usually mean one of them.
- Check state holidays separately: the federal list is the baseline, not the whole calendar for any one state.
Common mistakes to avoid
- Counting weekends as business days: a 358-day span has 102 weekend days in it, nearly a third of the total.
- Forgetting leap years: 2028 adds a day to any span that crosses 29 February.
Who is the date calculator for?
Project managers counting business days to a deadline, HR teams working out notice periods, travellers counting down to a trip, and anyone who needs to know what date is 90 days from now, or what day of the week a date falls on.
Related terms: days between dates, date difference calculator, business days calculator, add days to a date, what day of the week, federal holidays 2026, calendar days vs business days.
The holiday list is the 2026 US federal list, checked 10 November 2026. State and local holidays are not included.
Learn: how to use the Date Calculator
- Pick days between two dates, add or subtract from a date, or the day of the week for a date.
- Enter the dates, and choose whether to include the end day and subtract US federal holidays.
- Read the breakdown in years, months, weeks and days, plus the business-day count.
Features
- Days between dates in years, months, weeks and days
- Weekdays, weekend days and business days counted
- US federal holidays 2026 built in, editable on or off
- Include the end day or count between the dates
- Add or subtract days, weeks, months or years from a date
- Day of the week for any date, with leap-year check
- Holiday table for every federal holiday in the span
Worked example
From 1 January 2026 to 25 December 2026 is 358 calendar days: 11 months and 24 days, or 51 weeks and 1 day. Of those, 256 are weekdays and 102 are weekend days. Ten US federal holidays fall on weekdays inside the span, so business days are 246. Christmas Day is the end date, so it sits outside the counted days.
Frequently asked questions
How many days are there between two dates?
Subtract the start date from the end date. From 1 January 2026 to 25 December 2026 is 358 calendar days. The calculator also gives the breakdown: 11 months and 24 days, or 51 weeks and 1 day. Leap years are handled automatically.
What is the difference between calendar days and business days?
Calendar days count every day, including weekends and holidays. Business days count Monday to Friday only, minus US federal holidays when the holiday option is on. From 1 January to 25 December 2026 there are 358 calendar days but 246 business days.
What are the US federal holidays in 2026?
New Year's Day 1 Jan, Martin Luther King Jr.
Does the calculator include the end day?
Only if you choose it. By default it counts the days between the dates, so 1 January to 3 January is 2 days. With include end day on, the same span is 3 days. Most date-difference tools use the between count by default.
How do I add 100 days to a date?
Pick the add-or-subtract mode, enter the date and 100 days. 1 January 2026 plus 100 days is 11 April 2026. Use a negative number to subtract: 1 January 2026 minus 100 days is 23 September 2025.
What day of the week was 1 January 2026?
Thursday. The calculator gives the weekday for any date, plus whether the year is a leap year. 2026 is not a leap year; 2028 is. The same week runs Monday 29 December 2025 to Sunday 4 January 2026.
Why is Independence Day observed on 3 July in 2026?
Because 4 July 2026 falls on a Saturday. Under federal rules, a holiday that falls on a Saturday is observed on the preceding Friday for most federal employees, so federal offices close on Friday 3 July. Only one of the two dates is counted as a holiday.
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