Beginning of Month Formula Excel

What this does

EOMONTH returns the last day of the month a given number of months from a date. Passing 0 gives the end of the current month, -1 the end of the previous, 1 the end of the next. It is the correct way to build month-end reporting periods, payment terms and accrual dates, because it knows February has 28 days except when it has 29 — logic that hand-rolled date arithmetic gets wrong every four years. Pairing it with a +1 gives the first day of a month, which is the other half of a period boundary. The same idea underpins a lot of everyday Excel work, so the few minutes spent getting it right here pay back across every sheet you build afterwards. Treat it as a pattern, not a one-off, and it stops being something you look up and starts being something you reach for. Treat “beginning of month formula excel” as a small repeatable workflow rather than a one-off click you hope to remember next time. Use a small test block before the live file, so any surprise in the affected formula shows up while it is still harmless. When a formula is involved, keep the inputs labelled beside it, reference cells instead of typing values, and apply number formatting only after the result checks out. That turns a calculation you can defend to a CFO or an auditor into a method you can reuse, explain, and defend when the workbook leaves your screen.

A worked example

The end of the current month for a reporting cut-off: =EOMONTH(TODAY(), 0). The first day of the current month: =EOMONTH(TODAY(), -1)+1. Net-30 terms landing on a month end: =EOMONTH(A2, 1). Building twelve month-end dates down a column: =EOMONTH($A$2, ROW()-1). EOMONTH gets month ends right on the leap year that hand-rolled date arithmetic quietly gets wrong. A practical tip before you scale it up: build it once on a small block of test data, confirm the number against the tool on this page, and only then point it at your real sheet. That one habit catches almost every mistake while it is still cheap to fix, long before a wrong figure reaches a report or a colleague.

In Google Sheets

If you are in Google Sheets rather than Excel, the good news is that the formula shown here is identical and the workflow barely changes — menus sit across the top instead of in a ribbon, and a few function names differ slightly, but anything you build here moves across with little or no rework. The aim was to get you unstuck fast and leave you a little more capable than a copy-paste would. The answer is at the top, the tool proves it, and the detail above shows why it holds — so the next time a colleague asks, you can answer without reaching for search. Treat “beginning of month formula excel” as a small building block rather than a chore. Once the inputs sit in their own cells and the formula reads from them, the same setup answers a dozen related questions with a tweak, and Excel keeps every dependent figure current as the data changes. The tool above is there so you can rehearse and verify before committing anything to a real workbook; the steps and worked example are there so the logic sticks. Get it right once and it stops costing you time — it starts saving it, every time the question comes back around.

Common mistakes

• Hand-rolling month ends with DATE and a day count, which breaks on February and on 30-day months.
• Forgetting the second argument, which is required and has no default.
• Leaving the result unformatted, so it shows a serial number.

Frequently asked questions