Time & Date Calculators
Ages, date differences, durations and timesheets, with leap years handled properly.
- Age Calculator Exact age in years, months and days — plus totals and your next birthday. Time & Date
- Date Calculator Days between two dates, or add and subtract days, weeks, months and years. Time & Date
- Time Calculator Add and subtract hours, minutes and seconds, and convert to decimal hours. Time & Date
- Work Hours Calculator Hours worked from clock-in to clock-out, with breaks and overnight shifts. Time & Date
About these calculators
Dates and times are the easiest thing to get subtly wrong. Months have different lengths, one year in four has an extra day, and adding a month to 31 January has no obvious answer. Approximations like "days ÷ 365" drift by about ten days over a lifetime.
Everything in this category works on real calendar arithmetic — leap years by the full Gregorian rule, month-end clamping, and durations held in whole seconds so nothing rounds away. Dates are treated as plain calendar dates, so your time zone cannot shift an answer by a day.
Other categories
- Math Percentages, percentage change and fractions — the everyday arithmetic people look up most. 3 calculators
- Everyday Tips, discounts and sales tax — the quick sums you do in a shop or at a restaurant table. 2 calculators
- Construction Square footage and concrete volume for real projects, in both imperial and metric units. 2 calculators
- Design & Tech Aspect ratios and screen dimensions for video, photography and web design. 1 calculator