How to Calculate the Difference Between Two Dates
The date difference calculator tells you exactly how many days, weeks, months, and years separate any two dates. Simply enter a start date and an end date, then click Calculate — the result appears instantly without any manual counting.
This tool is useful any time you need to measure a span of time accurately. Common use cases include calculating how long until a project deadline, figuring out how many days remain in a contract period, working out notice periods for employment contracts, determining how long ago an event occurred, or calculating the exact duration of a lease or subscription.
Unlike counting on a calendar by hand, this calculator accounts for months of different lengths (28, 29, 30, or 31 days) and leap years automatically. You get the precise answer in seconds.
What the Results Mean
Total days — the raw count of calendar days between the two dates, including weekends and public holidays.
Weeks — total days divided into complete weeks, with remaining days shown separately.
Months — the number of complete calendar months between the dates.
Years and months — a combined breakdown, useful for contracts or tenancy agreements measured in years.
If you need to exclude weekends and public holidays from the count, use the Business Days Calculator instead, which supports public holiday calendars for 50+ countries.
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Frequently Asked Questions
How do I find the number of days between two dates?
Enter your start date and end date in the fields above, then click Calculate. The result shows the total days, weeks, months, and years between them instantly.
Does this calculator include the start date and end date?
By default the calculator counts from the start date up to (but not including) the end date — the same way most contracts and deadlines are measured. If you need to include both the start and end day, add 1 to the total days shown.
What is the difference between this and the business days calculator?
This tool counts all calendar days including weekends and public holidays. The Business Days Calculator counts only working weekdays and can exclude public holidays for 50+ countries — useful for contract deadlines and payroll calculations.
Can I calculate the difference in months and years?
Yes — the calculator shows the difference in total days, total weeks, total months, total years, and a combined years-plus-months breakdown, all at the same time.
How do I calculate how many days until a future date?
Enter today's date as the start date and your future date as the end date. The result shows exactly how many days remain. You can also use the Countdown Calculator which does this automatically using today's date.
Can this calculator handle leap years?
Yes. The calculator accounts for leap years automatically. February 29 is recognised as a valid date in leap years, and the day count is always accurate regardless of whether a leap year falls within your date range.
How do I calculate someone's age in days?
Enter the person's birth date as the start date and today as the end date. The total days result is their age in days. For a more detailed age breakdown including years, months, and days, use the Age Calculator.
What is the longest date range this calculator supports?
The calculator works with any dates in the Gregorian calendar. You can calculate differences spanning decades or even centuries with full accuracy.
Why might my result differ from a contract or legal document?
Legal documents sometimes count dates differently — for example, some count both the start and end day, while others exclude one or both. Always check how your specific contract defines the counting method if precision matters.