Calculate the exact number of days, weeks, months, and years between any two dates. Also add or subtract days from any date for project planning.
Select two dates to calculate the difference
The Schengen rule: max 90 days in any rolling 180-day window. This tool provides estimates — always verify with official sources for legal or visa purposes.
The Date Difference Calculator finds the exact span between two dates in days, weeks, months, and years — the core days between dates, or days between two dates, question — and can also add days to date or subtract them from a given date. Beyond basic date duration calculator math, it includes a work week selector for a working days calculator and business days calculator view, public holidays by country for 21 countries, and a dedicated Schengen day calculator covering the 90 180 day rule as a visa day tracker — making it useful for project managers, HR teams, travelers, and anyone working across international deadlines.
Enter a start and end date and the calculator computes the exact number of calendar days between them, then derives weeks, months, and a precise years/months/days breakdown that correctly accounts for leap years and varying month lengths — the same logic that makes it a reliable pregnancy weeks calculator (enter your last menstrual period as the start date) or lease duration calculator for tenancy timelines. Choosing a Work Week (Mon–Fri, Sun–Thu, or Sun–Fri) turns the tool into a work week selector that changes which days count as "off" — including a dedicated sun thu work week option for the Middle East — which in turn changes the estimated working-days total; adding a Country applies that country's typical annual public-holiday count from our public holidays by country data, scaled proportionally to your date range. The Schengen 90 180 calculator works differently — you log entry and exit dates for each trip, and it counts how many of those days fall within the rolling 180-day window ending on your chosen check date, comparing that total against the 90-day limit as a true schengen day calculator.
Getting a date calculation wrong has real consequences: missing a Schengen overstay under the 90 180 day rule by even one day can trigger entry bans, a legal notice period counted in the wrong day type can void a claim, and a project deadline that ignores holidays can blow a launch date. Seeing calendar days vs business days, working days, and holiday-adjusted estimates side by side makes it much easier to plan realistically instead of guessing.
The exact logic behind Total Days, Working Days, Exact Duration, and the Schengen day count
The calculator walks every calendar day from Start Date through End Date inclusive and classifies each by weekday using your selected Work Week (Mon–Fri, Sun–Thu, or Sun–Fri), counting how many fall on working days versus off days.
Estimated holidays = (Total Days ÷ 365) × the selected country's typical annual public-holiday count — a statistical approximation, not a lookup of that country's actual holiday calendar.
The tracker marks every day covered by each trip's entry and exit dates (inclusive) and counts how many fall inside a rolling 180-calendar-day window ending on your chosen check date.
Covers both the Date Difference mode and the Add/Subtract Days mode
In the Date Difference card, pick the two dates you want to measure between. The End Date must fall on or after the Start Date.
Select Mon–Fri, Sun–Thu, or Sun–Fri to match where the work happens, and pick a Country if you want an estimated public-holiday count added to the results.
Instantly see Total Days, Weeks, Months, Years, Working Days, Off Days, Exact Duration, and two charts breaking down the span.
In the "Add/Subtract Days" card, enter a From Date and a number of days — positive to add (e.g. 30) or negative to subtract (e.g. −14) — then click "Calculate Result Date".
The resulting date and day of the week appear immediately below. Use "⬇ Export Result" on the Date Difference card to download a plain-text summary of your calculation.
Two scenarios: a standard date range, and a leap-year edge case
Suppose you set Start Date to 2026-01-01 and End Date to 2026-07-24, with a Mon–Fri work week.
Compare the same "1 February to 1 March" range in a leap year (2024) versus a common year (2023).
Real-world scenarios where accurate date math matters
Calendar days include weekends and holidays. Working days exclude weekends based on your selected work week: Mon–Fri (most countries), Sun–Thu (Middle East, Israel), or Sun–Fri (6-day week). Subtract public holidays for precise project timelines — use the Country selector above to get an estimate for your period.
Add 90 calendar days for a quarterly timeline. For agile sprints, add 14 days per sprint. For contract milestones, subtract days from a deadline to set interim checkpoints. For cross-timezone deadlines, note that "end of day" differs between New York, London, and Singapore.
Legal deadlines often specify "calendar days" or "business days" depending on jurisdiction. Lease agreements, notice periods, and rental bonds depend on exact day counts — especially when crossing month or year boundaries. Always confirm which day type applies before relying on a calculation.
The Schengen Area allows a maximum of 90 days in any rolling 180-day window — one of the most searched date calculator use cases globally. Use the Schengen Tracker above to count days across multiple trips and see exactly how many days remain. Also useful for counting days present in any country for visa compliance.
Pregnancy duration is measured in weeks from the last menstrual period (LMP). A full-term pregnancy is approximately 280 days (40 weeks) from LMP to due date. Enter your LMP as the start date and today as the end date to calculate how many weeks pregnant you are — the exact duration appears in the results.
Calculate the exact length of a tenancy, lease, or notice period. Enter your lease start and end dates to find the total duration in months and days. Notice periods for rental agreements are often defined in calendar days — even a one-day difference can affect legal obligations.
Calculate an employee's tenure from hire date to today for service awards and anniversaries, work out accrued leave over a review period, or find a notice-period end date for resignations and terminations.
Count down to a wedding, conference, or product launch, or work backward from an event date using Add/Subtract Days to set vendor bookings, invitation mailing, and RSVP deadlines.
Calculate Net-30, Net-60, or custom invoice due dates from an issue date, or check how many days overdue a payment is against its due date.
Plan multi-leg trips by calculating the exact number of days between flights, hotel check-in and check-out dates, or how long a visa or travel-insurance policy remains valid.
Find the number of days or weeks in a semester or term, count down to an exam or application deadline, or calculate a student's total enrollment duration.
Calculate the exact number of days between two historical dates for research, genealogy, or journalism, correctly accounting for leap years across centuries.
Add a billing-cycle length (e.g. 30 or 365 days) to a subscription start date with Add/Subtract Days to find the next renewal date or a free-trial expiry date.
Calculate notice periods, cure periods, or option-exercise windows defined in a contract, and compare calendar-day versus business-day interpretations before a deadline passes.
What this Date Difference Calculator does well, and where it can't replace an official source
The Gregorian calendar data behind every date calculation on this page
| Month | Days (Common Year) | Days (Leap Year) |
|---|---|---|
| January | 31 | 31 |
| February | 28 | 29 |
| March | 31 | 31 |
| April | 30 | 30 |
| May | 31 | 31 |
| June | 30 | 30 |
| July | 31 | 31 |
| August | 31 | 31 |
| September | 30 | 30 |
| October | 31 | 31 |
| November | 30 | 30 |
| December | 31 | 31 |
A year is a leap year if it's divisible by 4, except for century years, which must be divisible by 400 — so 2024 and 2028 are leap years, but 2100 will not be, even though it's divisible by 4. This 400-year rule keeps the Gregorian calendar aligned with the solar year to within about one day every 3,300 years.
Summary: This Date Difference Calculator gives you an instant day/week/month/year breakdown between any two dates, a calendar-exact duration figure, a work-week-aware working-days estimate with 21-country holiday context, an add/subtract-days tool, and a dedicated Schengen 90/180 tracker — all free, client-side, and exportable. Pair it with the Age Calculator or Business Days Calculator for related date-math tasks.
Common questions about date calculations
Official references to complement this calculator — not a substitute for legal or immigration advice
Explore other date and time tools