Date Calculator API

Add or subtract years, months, weeks and days (or business days) to a date. Month ends are clamped: 31 January + 1 month = 28/29 February.

Add or subtract years, months, weeks and days from any date, or count business days only, and see the resulting date and its day of the week.

Input

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

start

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

operation

add or subtract the offset. (string, one of add, subtract, default "add")

years

Years to add or subtract (applied first, with months). (integer, 0 to 3650000, default 0)

months

Months to add or subtract. (integer, 0 to 3650000, default 0)

weeks

Weeks to add or subtract (5 business days each when businessDays is true). (integer, 0 to 3650000, default 0)

days

Days to add or subtract. (integer, 0 to 3650000, default 0)

businessDays

Count weeks and days as business days (Monday–Friday), skipping weekends. (boolean, default false)