Date Difference Calculator
Find the exact time between two dates, count business days for work planning, calculate a deadline's risk level, or list recurring dates at a fixed interval. Everything runs privately in your browser.
How to use the Date Difference Calculator
Pick a mode at the top of the tool. Date Difference gives you the gap between two dates in whichever unit you need — an exact years/months/days breakdown, a single total (days, hours, or minutes), or business days only. Work Planning is built for scheduling: it counts business days between a start and target date, lets you choose a holiday calendar, adds buffer days as a safety margin, and draws a mini timeline of the whole span. Recurring Dates lists every occurrence of a fixed interval starting from a given date — handy for billing cycles, checkups, or maintenance schedules.
Every result updates the page URL, so you can copy the bookmarkable link to save or share a calculation exactly as you configured it.
How are business days calculated?
Business day mode walks through every calendar day between the start and end date and keeps a running count, skipping two kinds of days:
Weekends are any Saturday or Sunday. Holidays come from the calendar you select — a built-in US or EU list of common public holidays, or your own custom list of dates. The same logic is used to add buffer days: the calculator steps forward one day at a time, only counting days that are not a weekend or holiday, until it has added the requested number of buffer days.
Frequently Asked Questions
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How do I calculate the exact number of years, months, and days between two dates?
Enter a start date and end date, then choose the "Exact (years, months, days)" precision mode. The calculator subtracts the dates using calendar-aware logic, borrowing from months and years the same way you would count by hand, so the result matches how people naturally describe age or duration.
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How are business days calculated?
Business day mode counts every day between the two dates, skips Saturdays and Sundays, and also skips any date in your chosen holiday calendar (US, EU, or a custom list). What remains is the number of working days available for the task.
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What holidays does the calculator include?
The US calendar includes New Year's Day, Memorial Day, Independence Day, Labor Day, Thanksgiving, and Christmas. The EU calendar includes New Year's Day, Labour Day (May 1), Christmas, and St. Stephen's Day (December 26). You can also switch to a custom list and enter your own holiday dates.
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What are buffer days in work planning mode?
Buffer days are extra working days added after your target end date as a safety margin for delays. The calculator adds them as business days, skipping weekends and holidays, and shows the resulting buffered deadline alongside the original one.
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How does the recurring date calculator work?
Enter a start date and an interval in days, and the calculator lists the next set of occurrences by repeatedly adding that interval, showing each resulting date and day of the week. It's useful for recurring bills, checkups, maintenance schedules, or any fixed-interval reminder.
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Is my data private?
Yes — all calculations run entirely in your browser using JavaScript. No dates you enter are transmitted to any server or stored anywhere. See our Privacy Policy for details.