Business Days Calculator API

Count working days between two dates, or add/subtract working days to a date, skipping weekends and an optional holiday list.

Count working days between two dates, or add business days to a date, skipping weekends (any days you choose) and your own list of public holidays.

Input

Send these as a JSON object. Unknown fields are rejected.

mode

count: working days from start to end. add: move start by days working days (negative to go back). (string, one of count, add, default "count")

start

Start date as YYYY-MM-DD. (string, up to 10 characters, required)

end

For count: end date as YYYY-MM-DD (dates are swapped if end is earlier). (string, up to 10 characters)

days

For add: whole number of working days to add (negative to subtract), up to ±50,000. The start date itself is never counted. (integer, -50000 to 50000)

weekend

Weekend days as comma-separated numbers, 0 = Sunday … 6 = Saturday. Default "0,6" (Saturday and Sunday); "5,6" for Friday–Saturday. (string, up to 20 characters, default "0,6")

holidays

Holidays to skip, one per line as YYYY-MM-DD optionally followed by a name, e.g. "2026-12-25 Christmas Day". (string, up to 20000 characters)

includeStart

For count: include the start date. (boolean, default true)

includeEnd

For count: include the end date. (boolean, default true)

listExcluded

Include the list of skipped weekend days and holidays in the response. (boolean, default false)