About DayMath
DayMath answers one kind of question well: how many business days, and which date.
What it is
DayMath is a set of free calculators for business days and dates. You can count the business days between two dates, add or subtract business days from a date, and see which holidays affected the answer. There is no sign-up and nothing to install.
Who it is for
- Shipping and orders: turning “3–5 business days” into actual dates.
- Payroll and accounts: counting working days in a pay period and finding the next business day for a payment.
- HR: notice periods, probation periods and leave balances counted in working days.
- Legal and administrative deadlines: a first estimate of a business-day deadline, before you confirm it with the court, agency or contract.
- School countdowns: how many weekdays are left until the last day of school.
Editorial standard
- Computed, not written by hand. Every date and number comes from one tested date engine. Pages show the answer as of the day they were built, and your browser recalculates it for your own date.
- Official sources. Holiday dates come from the U.S. Office of Personnel Management, the Federal Reserve and the New York Stock Exchange. Facts about banks, carriers or the law are linked to the organization that publishes them.
- Stated conventions. How the start and end dates are counted is written on every calculator and explained in full on the methodology page.
- Corrections. If an answer is wrong, we fix the rule, add a test for the case, and record the change in the methodology changelog. Report a problem.
What DayMath is not
DayMath gives general information for planning. It is not legal, financial or HR advice, and it does not know your employer’s schedule, your bank’s cut-off times or your state’s holidays unless you add them. See the terms of use.