How to use it
- Choose "Days between dates" or "Add or subtract days".
- Enter the start date (today is filled in).
- Enter the end date, or the amount and unit to add or subtract.
- Click Calculate.
Days between two dates
Enter a start date and an end date to get:
- the total number of days,
- the same span in weeks and days,
- the span in years, months and days,
- the number of weekdays (Monday to Friday).
By default the calculator counts the days between the dates: from January 1 to January 31 is 30 days. Tick Include the start date to count both ends (31 days), which is what you want for things like "how many days is the trip" or "how many days did the event run".
Example: from March 15 to December 25 of the same year is 285 days, or 40 weeks and 5 days, or 9 months and 10 days.
Adding or subtracting time
Choose + or −, enter an amount and pick days, weeks or months.
- Days and weeks are exact: 90 days after January 15, 2027 is April 15, 2027.
- Months keep the same day of the month: March 15 + 3 months = June 15. If the target month is shorter, the result moves to its last day: January 31 + 1 month = February 28 (or 29 in a leap year).
The result shows the new date with its weekday, the ISO week number and the number of calendar days in between.
Common uses
| Question | How to calculate |
|---|---|
| How many days until my vacation? | Days between today and the start date |
| What's the date 90 days from today? | Today + 90 days |
| When does a 30-day return window end? | Purchase date + 30 days |
| How long have we been together? | Days between your anniversary and today |
| What date was 6 weeks ago? | Today − 6 weeks |
| When is a 6-month follow-up? | Appointment date + 6 months |
Weekdays and holidays
The weekday count includes every Monday through Friday and doesn't skip federal or state holidays, because holidays vary by employer and state. If a deadline is defined in business days, subtract the holidays that apply to you, such as New Year's Day, Memorial Day, Independence Day, Labor Day, Thanksgiving and Christmas.
Legal and contractual deadlines often have their own counting rules (for example, whether the first day counts, or what happens when the last day falls on a weekend). Check the rules that apply to your situation.
Related calculators
- Age calculator: your exact age in years, months and days.
- Days left in the year: what day of the year it is and how many remain.
- Month calculator: add months or count months between dates.
- Day of the week calculator: what weekday a date falls on.
All calculations use calendar dates and run in your browser, so daylight saving time doesn't shift the results.
Frequently asked questions
How do I calculate the number of days between two dates?
Enter both dates and click Calculate. Tick "Include the start date" if you want to count both the first and last day.
What date is 90 days from today?
Choose "Add or subtract days", keep today as the start date, enter 90 days and click Calculate.
Does the calculator count weekends?
The total counts every calendar day. A separate weekday count shows Monday to Friday only.
Does it account for leap years?
Yes. February 29 is counted in leap years.
Are holidays excluded from the weekday count?
No. Holidays vary, so subtract the ones that apply to you.
Last updated: November 12, 2026