First Day of Month Calculator
Find the exact first calendar day and its weekday for any month and year with this free first day of month calculator. Select a month and enter a year to instantly see whether the first falls on a Monday through Sunday, along with the YYYY-MM-DD formatted date. Works offline with no signup required ever in Austin, Chicago, Miami, Denver, Seattle, and New York.
Use this free first day of month calculator to find the first calendar day and its weekday for any month and year, instantly online.
Calculator Inputs
About Month Start
Find the exact first calendar day and its weekday for any month and year with this free first day of month calculator. Select a month and enter a year to instantly see whether the first falls on a Monday through Sunday, along with the YYYY-MM-DD formatted date. Works offline with no signup required ever in Austin, Chicago, Miami, Denver, Seattle, and New York.
How the first-day algorithm works: The calculator constructs a JavaScript Date object for the 1st of the chosen month and year, then calls toLocaleDateString to determine the weekday name. The output shows both the formatted date and the weekday. For example, March 1 2026 falls on Sunday, while April 1 2026 falls on Wednesday. The tool handles all 12 months and any valid year, leap years included, automatically.
Weekday detection for business planning: When the first falls on a weekend, many organizations observe the next Monday. Austin agencies use this to schedule $8,000 monthly launches on the first business day. Chicago landlords adjust $2,200 rent-due dates when 01/01 falls on a Saturday. Miami event planners book $15,000 deposits on the first weekday of peak months. Denver accountants set 04/01 tax deadlines. Seattle HR teams align 01/01 benefit-enrollment starts with the first business day. New York banks process $12,000 payments on the first weekday.
Lease, billing, and subscription planning: When a lease states rent is due on the first of the month, the weekday matters for bank processing. A 01/01 that falls on Sunday pushes ACH to 01/02 or 01/03. Miami property managers use this for $2,200 rent cycles. Chicago teams track $5,000 monthly vendor payments. Denver schools align $80,000 annual budget starts with 08/01. Seattle SaaS companies schedule $2,500 per-user subscription renewals on the first of each month. New York publishers time $4,000 royalty disbursements.
Quarter and fiscal-year alignment: Q1 starts 01/01, Q2 on 04/01, Q3 on 07/01, and Q4 on 10/01. When these fall on weekends, the first business day shifts. Austin financial teams use this for quarterly-report deadlines. Chicago hospitals track 07/01 fiscal-year starts. Miami schools plan 08/01 academic-year budgets. Denver nonprofits align 10/01 grant-cycle starts. Seattle ports schedule 01/01 annual-contract renewals. New York firms track 04/01 tax-filing deadlines. The calculator shows the exact date and weekday instantly.
Year-over-year comparison: The first of January shifts weekdays each year. January 1 2026 is Thursday, January 1 2027 is Friday, and January 1 2028 is Saturday. This pattern matters for businesses that always start on the first. The tool helps plan 12-month billing cycles, annual subscription renewals, and year-end close schedules by showing which months begin on business days versus weekends.
Where it is used
Austin agencies scheduling $8,000 monthly campaign launches for Q1 2026 starting 01/05, Chicago landlords computing $2,200 rent-due dates when the first falls on weekends for lease cycles beginning 03/01, Miami event planners booking $15,000 venue deposits on the first weekday of 07/2026, Denver accountants setting 04/01 quarterly-close deadlines for $50,000 tax filings, Seattle nonprofits launching $5,000 monthly giving campaigns aligned to 01/01 first-business-day starts, and New York publishers scheduling $12,000 royalty payments on 01/01 of each contract year.
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
March 2026
January 2027
July 2026
Frequently Asked Questions
- Is the first day always the 1st?
- Yes. The first calendar day of every month is always the 1st, but the weekday changes each year.
- How do I find the first business day?
- Check the weekday. If it falls on Saturday or Sunday, the first business day is the following Monday.
- Does this handle leap years?
- Yes. February 1 is always the 1st regardless of whether the year is leap.
- Can I check any year?
- Yes. Enter any valid year from the past or future to see the first weekday.
- Is this free and offline?
- Yes. It works instantly offline with no signup required ever.
- Does the result include the weekday?
- Yes. You see both the YYYY-MM-DD date and the weekday name for the first of the month.