Date Difference Calculator
Calculate the exact number of days, weeks, and months between any two dates. Handles leap years automatically.
Time Until
831 days
2 years, 3 months
Days
831
Weeks
118
+5 days
Months
27
Count days between dates for plans, SLAs, and leave
Date-difference math powers project buffers, pro‑rata refunds, rental day counts, and HR leave accruals. Leap years and month lengths are baked into civil-date libraries; this page mirrors those rules in the browser.
Contrast calendar days vs business days if your contract mentions “5 business days”—that requires a separate holiday calendar this tool does not model.
Pair with the timezone converter when midnight boundaries span zones, and the cron generator when schedules are periodic rather than one-off spans.
For legal deadlines, always verify jurisdiction-specific rules; calculators are aids, not counsel.
Related tools
These free tools pair well with this page — open them in a new tab to finish your workflow.
Frequently Asked Questions
How is the date difference calculated?
The tool subtracts the earlier date from the later date. It counts calendar days first, then converts to weeks, months, and years. The calendar-based month count considers that months have different lengths (28–31 days).
Does it include the start and end dates?
By default, the tool counts the days between the two dates (exclusive of both endpoints). If you need to include the end date (e.g. for a project that ends on the final day), add 1 to the displayed day count.
How are leap years handled?
Leap years are fully accounted for. When calculating across a February 29, that extra day is included in the total day count.
Why does the month count sometimes seem off?
Months have different lengths, so month-based calculations can appear inconsistent. For example, Jan 31 to Mar 31 is 2 months, but Jan 31 to Feb 28 is 1 month. The tool uses calendar month arithmetic, not a fixed 30-day definition.
Can I calculate business days only?
This tool calculates calendar days. Business day calculations require knowing which days are weekends and accounting for public holidays, which vary by country. For business-day calculations, you'd need a specialized tool with locale support.
What is a Julian Day Number?
The Julian Day Number (JDN) is a continuous count of days since the beginning of the Julian Period (January 1, 4713 BC). It is commonly used in astronomy and date calculation software because it eliminates the complexity of months and years.
Can this calculate my age?
Yes — simply enter your birth date as the start date and today as the end date. The result gives your age in days, months, and years. For a dedicated age display, see the Age Calculator tool.