Date Calculator

Add or subtract years, months, weeks and days from a date to find the resulting date and its day of the week.

Result

Resulting date

Distance from the start date

yearsmonths
weeksdays

How it was calculated

About the resulting date

Calendar

Start / resulting dateDays in between

How to use the date calculator

  1. Choose the start date (today is filled in for you).
  2. Pick Add or Subtract.
  3. Enter any mix of years, months, weeks and days – leave the rest at 0.
  4. Press Calculate to see the resulting date, its weekday, and how far it is from the start date and from today.

Dates from today

The most-searched periods, counted from today (Sunday, October 18, 2026):

PeriodDate from todayDate before today
7 daysSunday, October 25, 2026Sunday, October 11, 2026
14 daysSunday, November 1, 2026Sunday, October 4, 2026
30 daysTuesday, November 17, 2026Friday, September 18, 2026
45 daysWednesday, December 2, 2026Thursday, September 3, 2026
60 daysThursday, December 17, 2026Wednesday, August 19, 2026
90 daysSaturday, January 16, 2027Monday, July 20, 2026
100 daysTuesday, January 26, 2027Friday, July 10, 2026
120 daysMonday, February 15, 2027Saturday, June 20, 2026
180 daysFriday, April 16, 2027Tuesday, April 21, 2026
365 daysMonday, October 18, 2027Saturday, October 18, 2025

How the date is worked out

The parts are applied in a fixed order so the result is always predictable:

  1. Years and months move the calendar month, keeping the same day number.
  2. If that day doesn't exist in the new month, the last day of the month is used.
  3. Weeks and days are then added as exact days (1 week = 7 days).
Example: March 15, 2026 + 6 months + 2 weeks
  • + 6 months → September 15, 2026
  • + 2 weeks (14 days) → Tuesday, September 29, 2026
Example: 45 days before December 25, 2026
  • December 25 − 25 days → November 30
  • − 20 more days → Tuesday, November 10, 2026

Adding months near the end of a month

Start dateOperationResultWhy
January 31, 2026+ 1 monthFebruary 28, 2026February has no 31st
January 31, 2028+ 1 monthFebruary 29, 20282028 is a leap year
March 31, 2026− 1 monthFebruary 28, 2026Last day of February
February 29, 2028+ 1 yearFebruary 28, 20292029 is not a leap year
August 31, 2026+ 1 monthSeptember 30, 2026September has 30 days

Days in each month

DaysMonths
31January, March, May, July, August, October, December
30April, June, September, November
28 or 29February (29 in leap years)

Common uses

  • Payment and invoice due dates (“net 30”, “net 60”)
  • Notice periods and contract end dates
  • Warranty, return and trial periods
  • Visa and permit validity
  • Pregnancy and medication schedules
  • Project milestones and countdowns

If weekends and holidays shouldn't count, use the Business Days Calculator instead.

Add days to a date in Excel or Google Sheets

You wantFormula (date in A2)
Add 30 days=A2 + 30
Add 3 months=EDATE(A2, 3)
Add 2 years=EDATE(A2, 24)
Add 10 working days=WORKDAY(A2, 10)

Frequently asked questions

What is the date 90 days from today?

It is Saturday, January 16, 2027. The table above lists other common periods, and the calculator handles any number of days, weeks, months or years.

Does the calculator count the start date?

No. The start date is day 0, so adding 1 day to Monday gives Tuesday – the usual rule for deadlines and due dates.

How do I subtract days from a date?

Choose Subtract (−), enter the number of days and press Calculate. The result is the earlier date and its weekday.

What is 6 months from a date?

The same day number six months later, for example March 15 → September 15. If that day doesn’t exist, the last day of the month is used.

Are leap years included?

Yes. Every calendar day is counted, including February 29 in leap years.

How many weeks is 90 days?

90 days is 12 weeks and 6 days. The result shows the distance in weeks and days for any period you enter.