Google Sheets date formulas for deadlines, months and working days
Calculate due dates, month boundaries, elapsed days and working-day schedules.
Written by JosephinePublished June 22, 2026Last updated July 26, 20268 min
Use TODAY for the current date, EOMONTH for month boundaries, NETWORKDAYS for working-day counts and WORKDAY for a due date that skips weekends.
Before you calculate dates without text-based mistakes, set up a clean source range and one result you can check by hand. That gives you a known answer before the sheet grows.
This article shows how to calculate dates without text-based mistakes. The sample sheet uses ordinary rows so you can copy the method into an existing file without rebuilding everything.
Google Sheets date formulas for deadlines, months and working days
- 01Make a safe copy
Duplicate the source tab or file before changing formulas, ranges or formatting.
- 02Set up the source rows
Add the fields needed to calculate dates without text-based mistakes. Keep one record on each row and one field in each column.
- 03Add the method
Enter =WORKDAY(B2,10,Holidays!A:A) in a test cell and check its first result.
- 04Check a known case
Pick one row whose answer you already know and compare it with the sheet result.
- 05Test the awkward rows
Check blanks, zeros, repeated entries and one row that should not match.
- 06Apply it to the full range
Copy the formula or rule only after the sample cases return the expected result.
Set up the sheet for Google Sheets date formulas
Keep the source table rectangular. A single header row, no merged cells and consistent cell types make the work much easier to check.
Place settings, fixed rates or allowed labels on a separate tab. Name them clearly so another person can read the file without tracing every cell.
- Store inputs as dates
- Set the Sheet locale
- List holidays in date cells
- Format elapsed days as numbers
Check the first result before copying it
A result that looks plausible can still be wrong. Work through one row manually, compare it with the Sheet and check every referenced cell.
Next, test a blank row and an unusual row. These two checks catch many range, type and copied-reference mistakes before they spread.
=WORKDAY(B2,10,Holidays!A:A)Keep the file reliable as new rows arrive
Leave input columns visually separate from calculated columns. Protect formulas when several people edit the same file, and keep dropdown lists or settings outside the main table.
Add a short check near the result: row count, unmatched count, last refresh time or a manual spot check. The right check depends on the job, but it should make a bad update easy to notice.
Questions people ask
How do I add days to a date?＋
For calendar days, add the number directly. For workdays, use WORKDAY.
How do I get the last day of a month?＋
Use EOMONTH with an offset of zero.
Why does a date formula show a number?＋
Dates are stored as serial numbers. Apply a date format to the result cell.
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