Date Calculator
Enter two dates to get the gap in days, weeks plus days, months plus days and Monday-to-Friday business days. Or start from one date, add or subtract a number of days, and see the resulting date and weekday. Free, no sign-up.
Mode
Difference Between Two Dates
How to Use the Date Calculator
- 1. Choose a mode. Difference between two dates measures a gap; Add or subtract days moves a date forward or back.
- 2. Enter the dates. The date fields start empty, so pick both dates — to count from today, enter today's date as the start.
- 3. For add or subtract, set the count. Choose Add or Subtract, type a whole number of days, and pick Calendar days or Business days (Mon-Fri).
- 4. Read the result. Difference mode shows total days, business days, weeks plus days and months plus days. Add mode shows the resulting date as year-month-day and its day of the week.
How the Difference Is Counted
The total is the number of days you would step through to get from the earlier date to the later one, so the start date is not counted and the end date is. Monday to Friday of the same week is 4 days. The order of the two dates does not matter — the calculator always measures from the earlier one.
Weeks plus days is the total divided by seven. Months plus days counts complete calendar months from the earlier date, then the days left over. Months are not a fixed length, so use total days for anything contractual and the month figure as a plain-language summary.
| Start | End | Total days | Weeks + days | Months + days | Business days |
|---|---|---|---|---|---|
| 2026-01-15 | 2026-06-30 | 166 | 23w 5d | 5m 15d | 118 |
| 2026-09-01 | 2026-12-18 | 108 | 15w 3d | 3m 17d | 78 |
| 2026-03-02 | 2026-03-27 | 25 | 3w 4d | 0m 25d | 19 |
Business Days and Deadlines
A business day here is any Monday to Friday. The count skips Saturdays and Sundays but not public holidays, which differ by country, employer and school. Adding business days works one day at a time and counts only weekdays: five business days after Friday 16 October 2026 is Friday 23 October, ten is Friday 30 October, and one business day after Saturday 17 October is Monday 19 October.
| From | Operation | Result |
|---|---|---|
| 2026-10-17 | Add 30 calendar days | 2026-11-16, a Monday |
| 2026-03-01 | Add 90 calendar days | 2026-05-30, a Saturday |
| 2026-10-17 | Subtract 30 calendar days | 2026-09-17, a Thursday |
| 2026-11-02 | Add 45 business days | 2027-01-04, a Monday |
| 2026-12-18 | Subtract 10 business days | 2026-12-04, a Friday |
The 45-business-day line shows why holidays matter: the result runs through US Thanksgiving (26 November), Christmas Day and New Year's Day, so a real deadline there would land later. Subtract the holidays that apply to you by hand, then add that many business days again.
Check how your deadline counts days
Rules differ on whether the first day counts. Many legal and academic deadlines exclude the day of the triggering event and include the last day — Federal Rule of Civil Procedure 6(a) is one example. If a policy counts both ends, add 1 to the difference shown here. When it matters, follow the wording of the rule, contract or syllabus.
Which Tool Do You Need?
| You want to… | Use |
|---|---|
| Count the days between two dates or find a deadline | This calculator |
| Find someone's exact age in years, months and days | Age Calculator |
| Add or subtract hours and minutes, or find the time between two clock times | Time Calculator |
| Get the ISO or US week number of a date | Week Number Calculator |
| Find the weekday of any date, including historical ones | Day of the Week Calculator |
Frequently Asked Questions
- How do I calculate the number of days between two dates?
- Choose Difference between two dates, pick the start and end date, and read Total days. It is the end date minus the start date, so 15 January to 30 June 2026 is 166 days. The same screen shows the span as weeks plus days and months plus days.
- Is the end date included in the count?
- The end date is included and the start date is not, so Monday to Friday of one week is 4 days. The business-day count follows the same rule: it counts each weekday after the start date up to and including the end date. To count both ends, add 1.
- What counts as a business day?
- Monday through Friday. Saturdays and Sundays are skipped, but public holidays are not, because they vary by country, employer and institution. If a holiday falls inside your range, subtract it by hand.
- How do I add business days to a date?
- Pick Add or subtract days, enter the date and the number, and set Day type to Business days (Mon-Fri). The calculator steps one day at a time and counts only weekdays, so adding 5 business days to a Friday lands on the Friday of the next week.
- How many days are there until a particular date?
- Enter today's date as the start and the target date as the end. The calculator does not fill in today's date for you, so type it or pick it from the date picker. The Total days figure is the countdown.
- Does it handle leap years and daylight saving time?
- Yes. Dates are counted as calendar dates in UTC, so 29 February is handled by the real calendar and a clock change cannot create an off-by-one-day error.