Home Add months to a date
Add months to a date
2026-01-31 plus 1 month is 2026-02-28. February 2026 has no 31st.
Add calendar months. If that month has no such day, the result is its last day. An empty box is not turned into zero.
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Why this exists
A lease, a course, and a deadline move by a count of months.
If that month has no such day, the result is its last day.
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01How to use it
Type a date and the months to add. A minus sign goes backward.
The green button fills 2026-01-31 and 1 month. The device button fills the box only when you press it.
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02What you get
The large text is the date you land on. If the day is shortened, the line says last day of that month.
An empty date stays a dash. Empty months leave the box empty and the result is the same date.
Entered2026-01-31 + 1 month
2026-01-31 + 1 2026-02-28 2024-01-31 + 1 2024-02-29 2026-01-15 + 6 2026-07-15 2026-01-31 + 2 2026-03-31 -
03Worth knowing
Adding 180 days to 2026-01-31 lands on 2026-07-30, so this page does not count that way.
A year outside 1 to 9999 is not calculated.
Questions
- QIs 2026-01-31 plus 1 month 2026-03-03?
- ANo. It is 2026-02-28.
- QDoes 2026-01-31 plus 2 months stay in February?
- ANo. It is 2026-03-31. March has a 31st.
- QDoes an empty month box become zero?
- AThe box stays empty, and only the result is the same date.
- QDoes this device's date appear by itself?
- ANo. The date of this device enters the box only when you press the button.
How this page works it out
This page adds calendar months to a date. 2026-01-31 plus 1 month is 2026-02-28. February 2026 has no 31st. 2024-01-31 plus 1 month is 2024-02-29.
2026-01-15 plus 6 months is 2026-07-15. 2026-01-31 plus 2 months is 2026-03-31. March has a 31st. 2024-02-29 plus 12 months is 2025-02-28.
Adding 180 days to 2026-01-31 lands on 2026-07-30, so this page does not add days. An empty date stays a dash, and this device's date enters the box only when the button is pressed. The result stays in this browser.