Last Day of Month

The last day of month calculator finds the final calendar date of any month — the 28th through 31st depending on the month and whether the year is a leap year — and shows which weekday it falls on. Month-end close, inventory counts, subscription cutoffs, and accrual journals all anchor to this date even when staff mentally picture the next month’s grid.

Month-end in finance and operations

General ledger teams post adjusting entries on the last calendar day of the period. Treasury teams reconcile cash as of that date. SaaS metrics often define monthly active users through the final second of the last day in UTC or US Eastern — but the civil label still comes from the calendar last day. Knowing its weekday tells you whether month-end work piles onto a Friday night or spills into a weekend.

Retail and warehouse operations schedule physical counts for the last day or the last business day before it. Those policies differ. This page gives the civil last day; combine it with business days calculator when only weekdays count.

How to use this calculator

Select a month and year or provide a reference date inside the month you care about. Calculate to read the last day as a spelled-out date and weekday. Leap February returns the 29th in leap years and the 28th otherwise without extra toggles.

For the matching first day, open first day of month. For how many days the month contains, use days in month.

28, 29, 30, and 31-day endings

April, June, September, and November end on the 30th. January, March, May, July, August, October, and December end on the 31st. February ends on the 28th except in leap years, when it ends on the 29th. The leap rule: divisible by 4, except centuries unless divisible by 400 — so 2026 follows the same test as any other year on this page.

People sometimes confuse last day with last weekday — for example last Friday of the month. That floating rule belongs on nth weekday of month with ordinal set to last, not here.

Countdowns to month end

Once you know the last date, measure remaining days with days until end of month from today or any start date. Billing teams use that span for proration when a customer joins mid-cycle.

Project managers who phrase deadlines as due by month end should publish the actual civil date in status reports. Saying January 31 beats saying end of January when the audience spans time zones.

Worked examples

An accountant closing 2026 books checks whether December 31 falls on a weekday or creates a three-day weekend with New Year’s observance. They verify observed holidays on 2026 holidays separately from the civil last day.

A magazine publisher mails issues on the last day of each month. When that day is Sunday, fulfillment may ship Monday. The weekday from this calculator triggers the shipping exception table without scanning a PDF calendar.

Year boundaries

December 31 is the fiscal year end for many US organizations on a calendar-year basis. January 31 ends the first month of the new year — useful when comparing year-over-year month-end workloads. Open the yearly 2026 calendar to see every month end at once.

ISO week numbering can label December 31 as week 1 of the next year even though the civil month has not changed. Week labels and month-end dates diverge near January 1 — note both when exporting to ERP systems.

Spreadsheets and APIs

Excel `=EOMONTH(date,0)` returns the last day of the month containing `date`. Google Sheets offers the same function. If your sheet shows serial numbers, format cells as dates before comparing to this page.

APIs that accept `YYYY-MM` ranges often infer the last day as the final valid day of that month. When an API rejects February 30, the fix is to compute month length first — this tool and days-in-month both answer that piece.

Accruals and cutoff language

Audit committees ask whether revenue was recognized as of month end. The civil last day from this page is the anchor; cutoff time-of-day belongs in policy footnotes. Systems that post at 23:59 Eastern still label the accrual with the calendar last day unless the contract defines otherwise.

Subscription products that renew on month end should display the numeric last date in confirmation emails — for example April 30 — rather than vague end-of-month wording that confuses customers in different time zones.

Inventory and retail cycles

Retail fiscal calendars sometimes use 4-5-4 patterns where month end does not match civil month end. Warehouse teams still reconcile physical counts against civil last day when the ERP uses standard months. Mark the civil date on cycle-count work orders to match this calculator.

When month end is Sunday, some chains move POS Z-reports to Monday morning while keeping the civil close label on Sunday. Document which timestamp your POS export uses before comparing to this page.

Comparing adjacent months

January 31 and March 31 both end on the 31st but fall on different weekdays each year. Listing last-day weekdays for a full 2026 planning season helps staffing models for month-end overtime without opening twelve separate PDFs.

Billing and subscription anchors

SaaS contracts billed on “last day of month” hit February 28 or 29 in 2026—confirm proration rules for short months before syncing to ERP. Rent due on month-end should note whether payment must arrive on that civil day or the preceding business day when banks are closed on federal holidays.

Accrual journals posted on month-end should note whether the ledger uses UTC midnight or corporate HQ local time for 2026 close.

Options expiring on month-end equity cycles should confirm exchange calendar for 2026 early closes rather than assuming every month ends at regular cash session time.

Related tools

More month tools on date tools: first day of month, days left in year, and quarter calculator for Q1–Q4 boundaries.