Three date calculators in one place: count the days between two dates, add or subtract days, weeks, months or years from a date, and find the date a number of days from today. Every result shows the weeks, the weekday and how it was counted.
Days between two dates
168 days
- In weeks
- 24 weeks
- Years, months, days
- 5 months, 15 days
- Weekdays (Mon–Fri)
- 120
- Business days (minus federal holidays)
- 113
- Hours
- 4,032
How it’s calculated
Days between = end date − start date (add 1 to count both dates).
Weeks = days ÷ 7, with the remainder in days.
Worked example with your numbers
- From September 28, 2026 to March 15, 2027: 168 days (end − start) = 168 days.
- 168 days ÷ 7 = 24 weeks.
- Calendar months: 5 months, 15 days (a month runs to the same day number of the next month; the last day is used when a month is shorter).
- Weekdays (Monday–Friday) in the span: 120; weekend days: 48.
- Business days after federal holidays on weekdays (7: Columbus Day, Veterans Day, Thanksgiving Day, Christmas Day, New Year’s Day, Birthday of Martin Luther King, Jr., Washington’s Birthday): 113.
Add or subtract days from a date
Sunday, December 27, 2026
90 calendar days after the start (12 weeks and 6 days) · 2026-12-27
How it’s calculated
Calendar: years and months are applied first (Jan 31 + 1 month = the last day of February), then weeks × 7 and days.
Business days: the start date is not counted; each weekend day and observed federal holiday is skipped.
Worked example with your numbers
- Start: Monday, September 28, 2026.
- + 90 days → December 27, 2026.
- Result: Sunday, December 27, 2026.
Official sources
Days from today
Thursday, February 11, 2027
12 weeks and 6 days from today · 2027-02-11
How it’s calculated
Calendar days: today + the number of days (every day counts).
Business days: today is not counted; Saturdays, Sundays and observed federal holidays are skipped.
Worked example with your numbers
- Today: Friday, November 13, 2026.
- + 90 days → Thursday, February 11, 2027.
“Today” follows your device’s calendar date.
Official sources
Frequently asked questions
How do you calculate the days between two dates?
Subtract the start date from the end date. The result does not count the start date; tick “Include the end date” to count both the first and the last day (+1 day).
How do I add days to a date?
Enter the start date, choose Add, and type the days, weeks, months or years. Months and years are added first — January 31 plus one month is the last day of February — then weeks and days.
Can it count business days only?
Yes. In “Add or subtract”, choose business days to skip weekends and U.S. federal holidays on their observed dates. To count business days between two dates, use the business days calculator.
How many weeks are between two dates?
Divide the days by 7. The days-between calculator shows the result as weeks and days.