Free Date Calculator — Days Between Dates & Age Calculator
Calculate days between dates, add or subtract days, or find an exact age with weekend controls, clear steps, and instant visual results.
Calculate the difference between dates
Compare two dates in calendar years, months, days, complete weeks, and Monday–Friday business days.
Add or subtract days
Move forward or backward from a date using calendar days or Monday–Friday business days.
Calculate exact age
Find completed years, months and days, total days lived, and the countdown to the next birthday.
Days between two dates
The difference mode uses date-only UTC arithmetic, so daylight-saving changes cannot turn a calendar day into 23 or 25 hours. Include the end day when both boundary dates count, or exclude weekends for a Monday–Friday total.
Add or subtract days
Choose a starting date, direction, and number of days. Calendar mode counts every day. Turn off “Include weekends” to skip Saturday and Sunday while moving in either direction.
Exact age calculator
Age is calculated in completed calendar years, then completed months, then remaining days. The result also shows total elapsed days and the number of days until the next birthday.
Leap years and long ranges
Real month lengths and leap years are preserved, including February 29. Ranges longer than 100 years use the same date-only arithmetic without relying on average month or year lengths.
Frequently asked questions
Is the end date included?
It is included by default. Clear “Include end day” to measure elapsed midnights only.
What happens when the start date is later?
The calculator keeps the direction, displays a negative day count, and explains that the start date is after the end date.
How are business days counted?
Business-day mode counts Monday through Friday and excludes Saturday and Sunday. It does not automatically remove public holidays.
Can the age date be in the future?
No. The calculator shows a clear error when the birth date is later than the selected “as of” date.
Method and privacy
All calculations run locally in your browser. Entered dates are not submitted by this tool. Results are suitable for planning; verify legal, employment, banking, and filing deadlines with the relevant authority.
