Pick two dates and times to get the duration between them — broken down into days, hours, minutes, and seconds, plus a business-day count. Everything runs in your browser.
Measuring a life rather than an interval? The age calculator counts in calendar years, months, and days, and handles birthdays on the 31st and February 29. Adding up a week of shifts instead? The time card calculator totals clock-in and clock-out times with breaks, overnight shifts, and overtime.