First Day of Month Calculator

Find month-start date.

Find the first day of any month instantly. Free month-start date calculator.

About Month Start

Find month-start date.

Computes the first calendar day of the month.

Where it is used

Reporting periods, subscription renewal.

How to use the Month Start

Month — enter the value.
Year — enter the value (e.g. 2026).
Calculate — press the Calculate button to see the result instantly above.

Formula

new Date(year, month-1, 1).

Examples

Mar 2026

month:3

year:2026

Result: First day of month 3/2026: 2026-03-01

Frequently Asked Questions

Same every year?: Yes — always the 1st, weekday varies.