Date Calculator
Calculate the exact time between two dates — in years, months, weeks, days, weekdays, and hours — or add and subtract years, months, weeks, and days from any date.
Frequently Asked Questions
How do you calculate the number of days between two dates?
Count the actual calendar days elapsed, accounting for leap years and varying month lengths. Divide by 7 for whole weeks. This calculator also breaks the gap into exact years, months, and days (e.g. 1 Jan 2024 → 15 Mar 2026 = 2 years, 2 months, 14 days = 804 total days) and counts business weekdays (Mon–Fri) separately.
How do leap years affect date calculations?
A leap year adds 29 February, making the year 366 days. Leap years occur every 4 years, except century years not divisible by 400 (1900 was not a leap year; 2000 was). Any date range spanning a 29 February includes that extra day — which is why "one year" from 1 March 2023 to 1 March 2024 is 366 days, not 365.
How do you add months to a date correctly?
Adding months moves the month number forward while keeping the day where possible. When the target month is shorter, the date clamps to its last day: 31 January + 1 month = 28 February (or 29 in a leap year). This calculator applies years first, then months, then weeks and days — the convention used by most date libraries and spreadsheet software.
How many working days are there between two dates?
Working days exclude Saturdays and Sundays (and public holidays, which vary by country and are not counted here). A typical year has 260–262 weekdays. As a rule of thumb, multiply calendar days by 5/7: a 90-day project window contains roughly 64 weekdays. Use the weekday count in this calculator for deadline and payroll planning.