Quick Answer & Formula
Excel
Sheets
Beginner
=EDATE(start_date, months) To add N months to a date, use =EDATE(StartDate, N). To subtract N months, use a negative number: =EDATE(StartDate, -N). Always format the result cell as Short Date.
How to Add Months to a Date in Excel & Google Sheets (EDATE)
Adding months by simply adding + 30 days causes date drift over time because months have 28, 29, 30, or 31 days. EDATE preserves the exact calendar day.
1. Core Syntax & Examples
| Goal | Formula | Input Date | Resulting Date |
|---|---|---|---|
| Add 1 Month | =EDATE(A2, 1) | 08/15/2026 | 09/15/2026 |
| Add 1 Quarter (3 Mos) | =EDATE(A3, 3) | 08/15/2026 | 11/15/2026 |
| Add 1 Year (12 Mos) | =EDATE(A4, 12) | 08/15/2026 | 08/15/2027 |
| Subtract 6 Months | =EDATE(A5, -6) | 08/15/2026 | 02/15/2026 |
2. Dynamic Contract Expiration Model
If contract start is in B2 and term length in months is in C2:
=EDATE(B2, C2)
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Frequently Asked Questions
What happens if I add 1 month to January 31st?
EDATE automatically adjusts to the last valid day of the target month (e.g. EDATE(1/31/2026, 1) returns 2/28/2026).