How to use the date calculator
In Days between mode, pick a From date and a To date — type them or use the picker. The gap appears at once as a total in days, then as weeks and days and as years, months and days. Below that you get a table of totals, the weekday each date falls on, and which day of the year the end date is.
Switch to Add / subtract to go the other way: pick a start date, choose Add or Subtract, and enter any mix of years, months, weeks and days. The calculator returns the resulting date and its weekday.
How many days between two dates
The plain day count is the number of calendar days from the start date to the end date. By default the start date is not counted and the end date is — the same as counting nights between them. If you need both the first and last day included, tick Include the end date and the total goes up by one.
How days, weeks, months and years are counted
Total weeks is the day count divided by seven, with any remainder shown as extra days. The years, months and days figure is a calendar breakdown: whole years first, then whole months, then the days left over — so 1 January to 1 March reads as "2 months", not "59 days". Month lengths and leap years are handled automatically.
Add or subtract days from a date
Adding a period works calendar-first. Add one month to 31 January and you land on 28 February (or 29 in a leap year), because February has no 31st — the date clamps to the last valid day. Weeks and days are then added as exact 7-day and 1-day steps. Subtracting works the same way in reverse.
Business days only (excluding weekends and holidays)
Tap Go advanced and turn on Count business days only to count just Monday-to-Friday dates in the range; the weekend days are shown separately and shaded on the timeline. Turn on the second option to also drop the 11 US federal holidays (New Year's Day, MLK Day, Presidents' Day, Memorial Day, Juneteenth, Independence Day, Labor Day, Columbus Day, Veterans Day, Thanksgiving and Christmas), each shifted to its observed weekday.
Why "include end date" changes the answer
"How many days from Monday to Friday" has two right answers. If you mean how many nights, it's 4. If you mean how many days are you there, counting both Monday and Friday, it's 5. Leaving the box unticked gives the first; ticking it gives the second. Rental periods, trip lengths and notice periods usually want the end date included.
Counting days from today
To find how many days until a deadline, set the From date to today and the To date to the target. The day-of-year line tells you how far through the year that date sits, and the timeline puts a today marker in place so you can see the run-up at a glance.
Date math and leap years
A leap year adds 29 February, so any span crossing late February of a leap year is one day longer than the same span in a common year. The calculator uses real calendar dates throughout, so leap days, month lengths and year boundaries are always counted correctly — no need to adjust anything by hand.
What you get
| Output | Example |
|---|---|
| Total days | 90 |
| Weeks and days | 12 weeks, 6 days |
| Years, months, days | 2 months, 30 days |
| Weekday of each date | Wednesday → Tuesday |
| Business days | 64 (26 weekend days) |
| Resulting date (add / subtract) | 1 Apr 2026, a Wednesday |
Common uses
Contract terms and notice periods, invoice and payment due dates ("net 30"), project and sprint planning, visa and passport windows, return-by dates, warranty and returns cut-offs, counting down to an exam, wedding or trip, and working out how many days old something is. For an age from a date of birth, use the Age Calculator; for the rest of your quick-number jobs, the Percentage Calculator.
Common questions
How many days are between two dates?
Enter a start and end date and you get the exact number of calendar days between them, plus the gap in weeks, and in years, months and days. Leap years and month lengths are handled for you.
Does it count both the start and end date?
By default, no — it counts the nights between them, so the start date is excluded and the end date included. Tick "Include the end date" to add one day, which is what you want when both the first and last day count.
How do I add 90 days to a date?
Switch to Add / subtract mode, pick your start date, keep the direction on Add, and put 90 in the Days field. You'll get the resulting date and its weekday. Years, months, weeks and days can be combined in one go.
How many working days are there between two dates?
In Days between mode, tap Go advanced and turn on "Count business days only". It counts Monday-to-Friday dates and shows the weekend days separately. The second option also removes the 11 US federal holidays.
How many days until a specific date?
Set the From date to today and the To date to the day you're counting to. The total days is your answer, and the timeline marks where today sits in the span.