Add or subtract years, months, weeks and days to a date. Runs on your device.
Years and months go first, as calendar months, and weeks and days go second, as whole days. A year counts as 12 months. The page opens on today with 1 month and 10 days added, and the box under the answer, How this was worked out, shows each of the two steps with your dates. The start date itself is not counted: adding 1 day to 9 October gives 10 October. The same order is used when you subtract, so 31 March minus 1 month and 1 day is 28 February minus 1 day, which is 27 February in a year that is not a leap year. The fields accept whole numbers from 0 up to 9,999 years, 120,000 months, 600,000 weeks and 3,700,000 days. Empty fields count as 0.
A month is not a fixed number of days, so adding months can land on a day that does not exist. When that happens the date moves back to the last day of the target month. 31 January 2024 plus 1 month is 29 February 2024, because 2024 is a leap year, and 31 January 2023 plus 1 month is 28 February 2023. 31 March plus 1 month is 30 April. The clamp is applied once, after all the years and months have been added, not month by month, so 31 January plus 2 months is 31 March and not 28 March. A 29 February start plus 1 year is 28 February of the next year, unless that year is also a leap year. Dates before 1 January 0001 or after 31 December 9999 are not supported, and the page shows a message instead of a date.
The main answer is the date in words, such as 19 November 2026, with the same date in ISO form, 2026-11-19, which is handy for spreadsheets and forms. The weekday is worked out from the calendar, not from your device. The last tile says how many days the result is from the start date, for example 41 days after the start date, or 41 days before it when you subtract. That count includes the effect of month lengths, so adding 1 month to 9 October is 31 days. The page does not skip weekends or holidays. To add working days use the business days calculator. To find the gap between two dates that you already have, use the date difference calculator.
No. This page starts from one date and adds or subtracts an amount. To count the years, months and days between two dates you already have, use the date difference calculator, which is part of the age calculator page.
It is the last day of February: 28 February in most years and 29 February in a leap year such as 2024. The day number 31 does not exist in February, so the date moves back to the month's last day. The same happens for 31 March plus 1 month, which is 30 April.
Yes, always. Years and months move the calendar first, with the end-of-month rule, and then weeks and days are added as whole days. The order matters near month ends: 31 January plus 1 month and 1 day is 29 February plus 1 day, which is 1 March in 2024.
Yes. An empty start date means today, taken from your device's clock when the page runs. The notice under the answer says when today was used. Type a date if you want to be sure which day the sum starts from.
Not usually. Adding 1 month keeps the day of the month where it can, while adding 30 days moves exactly 30 days. From 9 October they give 9 November and 8 November. They also differ in February and in 31-day months.
No. Every calendar day counts. For a count that skips weekends and typed-in holidays use the business days calculator.