Date Calculator
Work out the difference between two dates, business days and exact age.
Pick both dates to see the difference.
Pick both dates to count business days.
Pick a date of birth to calculate the age.
How many days are between two dates?
To find out how many days are between two dates, enter a start date and an end date: Docuboxer's date calculator instantly returns the difference in years, months and days the way a person would count it, plus totals in days, weeks, months and hours. It bundles three more modes: add or subtract days, weeks, months or years from a date; count only the business days between two dates, excluding weekends and holidays you paste in yourself; and work out an exact age from a date of birth, with the next birthday and how many days are left. Calculations handle leap years correctly (2000 was one, 1900 wasn't) and clamp month-end additions, so January 31 plus one month lands on February 28 or 29, not March 3. Everything runs locally in your browser, no date is ever uploaded anywhere, and it's completely free with no signup.
How to use Date Calculator
- Pick the mode you need at the top: date difference, add/subtract, business days or exact age.
- Select the date or dates using each field's calendar picker.
- In business-days mode, check the exclude-holidays box and paste one date per line if you want to skip holidays too.
- Check the result, which updates automatically as soon as the required fields are filled in.
- Copy the result to your clipboard with one click from the action buttons.
Common use cases
Working out legal and tax deadlines
Count the exact number of business days left to file an appeal, respond to a claim or submit a tax return, excluding weekends and the official holidays that apply in your jurisdiction.
Planning vacation and time off
Calculate how many calendar or business days a leave period covers before requesting it, or find the exact date that falls two weeks after your last day at work.
Estimating project timelines
Add a delivery window in weeks or months to a project's start date to get the real deadline, or check how many days you've been working on something since it kicked off.
Verifying minimum age for a process
Check someone's exact age in years, months and days from their date of birth — useful for anything with a minimum-age requirement, from a driver's license to retirement eligibility.
Tracking birthdays and anniversaries
Find out how many days are left until someone's next birthday, or which day of the week a wedding anniversary will fall on several years from now.
Frequently asked questions
How do I calculate how many days are left until a date?
Use the "Difference between dates" mode: set today as the start date and your target date as the end date. The result shows the total number of days left, plus a years/months breakdown when it applies.
How are business days between two dates calculated?
The calculator counts every day between the two dates, both inclusive, and drops any that fall on a Saturday or Sunday. If you turn on "Exclude holidays" and paste in a list of dates, those days are excluded too.
Why does January 31 plus one month give February 28, not March 3?
Because February doesn't have 31 days. The calculator clamps the result to the last day of the target month instead of overflowing into the next one — which is how a calendar-based date calculation is expected to behave.
Does it account for leap years?
Yes, including the century leap-year rule: 2000 was a leap year (divisible by 400) but 1900 wasn't (divisible by 100 but not by 400). This affects both the date difference and the age calculation.
Why isn't the date difference the same as dividing total days by 30?
Because the years/months/days breakdown is calculated against the real calendar, respecting how many days each specific month actually has, not an average approximation. It's the same way a person would count the difference by hand.
Is my date of birth or any other date uploaded to a server?
No. Every calculation runs in JavaScript directly in your browser. No date ever leaves your device, and the tool is free, with no signup and no usage limit.