Date Calculator
Compare two dates, or add and subtract years, months, and days. Calendars use your local timezone.
Difference between two dates
Add or subtract from a date
About Date Calculator
Calculate the difference between two dates, or add and subtract years, months, and days from any date with this free online date calculator. Use it for project deadlines, notice and contract periods, billing cycles, visa and travel planning, and sprint math without counting on a paper calendar. Results show the span in several units so you can pick days, months, or years as needed.
Project managers add working-style offsets to a start date to get a due date. HR and operations people compute notice periods. Finance people look at billing windows. Students compute assignment spans. Adding a month is not always 30 days, and leap years exist; a calculator that uses real calendar rules avoids off-by-one mistakes that a raw 86400 second multiply would make.
Pick two dates to see the difference, or pick one date and an offset to move forward or backward. The output is immediate and copy-friendly. For age from a birth date, the age calculator is more specific. For Unix numbers, use the timestamp or epoch tools. This page is for civil calendar dates and offsets.
All calculations run in your browser with no data sent anywhere. Personal deadlines and contract dates stay private. Use this free date calculator and date difference calculator whenever you need accurate calendar math online.