Calculate the number of days, weeks, months and years between two dates. Includes business-day counting that excludes weekends, plus an add/subtract days mode.
Business day counts exclude Saturdays and Sundays but not public holidays, which vary by country and state.
Find the exact number of days, weeks, months and years between any two dates, including a business-day count that skips weekends. Switch modes to add or subtract a period from a starting date instead.
There is no universally correct answer to “how many days from Monday to Friday.” Exclusive counting gives 4, which is what you want for elapsed time and interest calculations. Inclusive counting gives 5, which is what you want for “days of vacation” or a rental period where both the first and last day are charged. Contracts and statutes differ, so check which convention applies before relying on a deadline.
Adding one month to 31 January gives 28 February, because 31 February does not exist and the result is clamped. But subtracting one month from 28 February gives 28 January, not 31 January. You cannot reliably round-trip month arithmetic, which is a frequent source of billing and subscription bugs.
The business-day count here excludes Saturday and Sunday only. Public holidays are deliberately left out because they differ by country, state and industry - US federal holidays, UK bank holidays and stock market closures are all different sets. If your deadline is holiday-sensitive, count them separately.
Pick a mode
Choose whether you want the difference between two dates, or to add and subtract a period from one date.
Enter your dates
Order does not matter for the difference mode - the calculator always reports a positive duration.
Choose your counting rules
Decide whether the end date is included, and whether to count business days only when adding or subtracting.
Project deadlines
Work out a delivery date a set number of business days from today, skipping weekends.
Contracts and notice periods
Calculate notice, cooling-off and payment terms with the correct inclusive or exclusive convention.
Event countdowns
Find exactly how many days remain until a wedding, launch or travel date.
Payroll and invoicing
Count working days in a period for timesheets, billing and accrual calculations.
Subtract the earlier date from the later one and divide by the length of a day. By default the count excludes the end date, so 1 January to 8 January is 7 days. Tick 'include the end date' if you need an inclusive count, which contract and rental periods often use.
A business day is any weekday from Monday to Friday. This calculator excludes Saturdays and Sundays. It does not exclude public holidays, which vary by country and even by state, so subtract those separately if your deadline depends on them.
When the target month is shorter than the starting month, the result is clamped to the last valid day. Adding one month to 31 January gives 28 February (29 in a leap year), because 31 February does not exist. This matches how most business and legal systems handle it.
Yes. All calculations run on real calendar dates, so leap days are automatically included. This is why an exact day count between two dates does not equal the number of years multiplied by 365.
Two reasons. First, whether the end date is included is a convention, not a fact - both are valid. Second, timezone handling: naively parsing a date string in local time can shift it by a day. This tool works entirely in UTC to avoid that.