Add a month to a date without drifting
Adding 30 days looks right until it lands on the 2nd of the wrong month. This is the trap behind every subscription date.
The data
| Row number | A | B | C |
|---|---|---|---|
| 1 | Customer | Signed | Renews |
| 2 | Novak Ltd | 2026-01-31 | |
| 3 | Rossi GmbH | 2026-03-15 | |
| 4 | Silva SA | 2026-05-30 |
Your task
Put a formula in C2 that returns the date one month after the signing date in B2.
Your formula goes in C2
The checker compares your formula against the accepted answers — it does not run it. The expected result is shown with the solution so you can verify it in your own spreadsheet.
Why this is the right formula
B2 is 31 January, and there is no 31 February — so EDATE clamps to the 28th. Adding 30 days instead gives 2 March, which puts the renewal in the wrong month and drifts further with every cycle. That clamping is the whole reason EDATE exists rather than being a plus sign.
Try next
Free to use, share and republish — including commercially. Attribution isn't required, but it's what keeps these free to make, and there's one ready to paste below.
Questions
Does this actually run my formula?
No, and it is worth being clear about that. The checker normalises what you type — case, spaces, the semicolon-or-comma separator, dollar-sign anchors — and compares it against every formula that solves the task. The expected result is shown so you can verify it independently in your own spreadsheet.
My formula is different but correct. Will it be marked wrong?
It should not be: each exercise accepts the genuinely different approaches, not one blessed answer. If you find a correct formula that is rejected, the feedback button sends it to us with the page attached.
Do I need an account?
No. There is no signup, no progress tracking and nothing stored — everything happens in your browser.