Date Calculator
Calculate days between dates, or add/subtract years, months, and days from any date.
There is more than one way to count days
Difference with total weeks
The difference mode reports years, months, and days between two dates and adds the total days and total weeks, so you get both the breakdown and the whole picture.
Add and subtract dates
Shift any date forward or backward by years, months, weeks, or days, with negative values allowed and leap-year rules applied automatically to every calculation.
Real month lengths
Calendar math follows real month lengths of 28 to 31 days and leap years instead of fixed 30-day months, so deadlines and anniversaries land on the right date.
What Is a Date Calculator?
A date calculator answers the two calendar questions that come up constantly in planning: how much time lies between two dates, and what date results from adding or removing time from a known date. The difference mode reports the interval as years, months, and days, alongside the total days and total weeks, and can count only weekdays when you need working days rather than calendar days. The add-and-subtract mode shifts any starting date by years, months, weeks, or days — forward or backward — with leap-year rules handled automatically. Contract deadlines, school schedules, and travel plans all produce this kind of arithmetic.
What this tool can do
- 🔁 Two working modes: measuring an interval, and shifting a date.
- 📆 The interval between two dates, expressed as years, months, and days plus total days and weeks.
- 💼 An option to exclude Saturdays and Sundays, revealing how many working days an interval contains.
- ➕ Adding years, months, weeks, or days to any chosen starting date.
- ➖ Subtracting the same components to land on a date in the past.
- 🗓️ Correct handling of February 29 and leap years when shifting dates across year boundaries.
When would you use it
- 📋 Verifying whether a promised delivery deadline actually fits inside the allowed window.
- ✈️ Counting the days between booking a trip and departure, for visa or planning purposes.
- 🏫 Working out how many school days remain before a holiday break.
- 🏢 Calculating a notice period in working days rather than calendar days.
The calculation is performed entirely in your browser, so dates you enter are never uploaded or saved. A limitation to keep in mind: the working-days count excludes weekends only — public holidays differ from country to country, so no single tool can subtract them automatically; if a holiday falls inside your interval, subtract it yourself.
Inclusive, exclusive and business days
- Subtracting dates answers how-long-between (exclusive); contracts often want both endpoints counted (inclusive) — one more day.
- Business-day mode skips weekends; holiday sets differ per country and are not auto-included.
- The weeks-and-days remainder is integer division — 45 days makes 6 weeks plus 3 days.
Frequently asked questions
How does date difference calculation work?⌄
Counts days between two dates using precise date arithmetic, broken into years/months/days plus totals.
How are business days calculated?⌄
Excludes Saturday and Sunday. Public holidays are not excluded — adjust for your country's specific holidays.
How does date add/subtract work?⌄
Pick a base date and positive/negative amounts. Processes years first, then months, then weeks+days, handling month-end boundaries correctly.
What happens with month-end dates?⌄
Adding 1 month to Jan 31 → Feb 28/29. The calculator caps at the last valid day of the target month.