Time and Date Tools
Time math operates on a base-60 system rather than base-10, making manual calculations prone to error. Our time and date tools allow you to perfectly calculate the difference between calendar dates, elapsed hours, and precise chronological age.
Calculators
Our free online time and date tools to help you calculate and plan.
Related Guides
Learn more with our comprehensive guides and articles.
Glossary Terms
Key definitions you should know.
Worked Examples
Step-by-step examples showing exactly how the math works.
Time Worked on a Project
Because time operates on a base-60 scale, you cannot subtract 8.45 from 14.15. You must calculate the minutes up to the next hour (15 mins to 9:00 AM), count the hours (5 hours to 2:00 PM), and add the remaining minutes (15 mins).
View in Calculator →Frequently Asked Questions
Why is time math difficult?
Time relies on a base-60 system (60 seconds in a minute, 60 minutes in an hour) which means standard decimal subtraction does not yield correct results for hours and minutes.