Working Days Between Dates Calculator

Reviewed by the CalculatorHub team, edited by James Graham. Method from US OPM Federal Holidays and Leave. Last verified 2026-06-23.

The Working Days Between Dates Calculator computes working days between dates from the relation working days = count of Monday to Friday serial days from start to end inclusive. It takes 6 inputs (start year, start month 1 to 12, start day 1 to 31, end year, end month 1 to 12, end day 1 to 31) and returns the working days between dates. Because this is a pure mathematical or physical formula rather than a jurisdiction-specific rule, the result never changes over time: the same inputs always produce the same answer, so you can rely on it whether you are checking homework, sizing a design, or sanity-checking another tool. Enter your values in the fields below and the result updates instantly; you can also share a permalink that pre-fills the exact calculation, which is useful for teaching, reports, or collaboration. For example, with start year = 2024, start month 1 to 12 = 1, start day 1 to 31 = 1, end year = 2024, end month 1 to 12 = 1, end day 1 to 31 = 14, the working days between dates works out to 10, and the worked example further down the page shows every step so you can follow the arithmetic and reproduce it by hand. The method is the standard form documented by US OPM Federal Holidays and Leave, and the figure above each result carries the date it was last verified. This tool is general information and is not a substitute for professional engineering, medical, financial, or scientific advice; always check critical results against the primary source and your own judgement.