How to Add or Subtract Days From a Date
Three steps to shift any start date forward or backward.
Pick the start date
It defaults to today after the page loads. Change it for any past or future anchor, or use a “days from today” preset.
Choose add or subtract
Enter the amount and unit — days, weeks, months, or years. For weekdays only, keep Unit on Days and turn on business days.
Read the resulting date
See the weekday, full date, year, and how far that day is from your start date in calendar days.
How the Calculation Works
Calendar days, weeks, months, and years use date-fns helpers so leap years and end-of-month edges stay correct. Business-day mode (Days only) walks forward or backward one day at a time and skips non-working weekdays and optional selected holidays with the same shared logic as the Business Days Calculator. Adding months follows date-fns clamping: January 31 plus one month becomes the last day of February.
Common Uses
A date calculator helps whenever you need “date plus X days” or a weekday a set number of business days out.
Deadlines and notice periods
Project a due date thirty or ninety days from a filing or notice start.
Delivery and shipping estimates
Add calendar or business days to an order date for an ETA window.
Pregnancy and project planning
Count weeks or months ahead from a known start without a spreadsheet.
Warranty and return windows
Subtract or add the policy length to see the last valid return day.
Frequently Asked Questions
Adding days, months, business days, and leap years.
How do I add days to a date?
Choose a start date, select Add, enter an amount, and pick Days (or Weeks, Months, or Years). The resulting date updates as you type. Presets like +30 or +90 days fill the amount relative to today for common “days from today” questions.
How do I subtract days from a date?
Use the same form with Subtract selected. Enter how many days, weeks, months, or years to go backward from the start date. A negative amount also flips Add and Subtract automatically; the count used is always the absolute value.
What date is 90 days from today?
Click the +90 days preset (or set Start Date to today, Add, Amount 90, Unit Days). The result panel shows the calendar date, weekday, and how many calendar days later that is. You can switch to business days only if you need ninety weekdays instead of calendar days.
What happens when I add a month to January 31?
Month and year math uses date-fns, which clamps to the last valid day of the target month. Adding one month to January 31 lands on the last day of February (28 or 29 in a leap year), not March 2 or 3. The same end-of-month behavior applies when subtracting months.
Does this calculator exclude weekends or holidays?
Only when Unit is Days and Business days only is on: non-working weekdays (Saturday and Sunday by default) are skipped, and under More options you can choose a country holiday list, change the weekend pattern, or add custom days off — the same shared logic as the Business Days Calculator. Weeks, months, and years always use calendar arithmetic.
Does this account for leap years?
Yes. date-fns uses the Gregorian calendar, so February 29 in leap years is handled correctly when you add or subtract days, weeks, months, or years across that date.
Related Calculators
Count spans, working days, or exact age on CalcDaily.