Date & Time Calculators

Calculate age, date differences, date arithmetic, elapsed time, work hours and weekly time cards. This hub groups closely related tools so you can move from a broad question to the calculator that matches the exact job.

Each calculator opens with the working tool first, followed by the formula or method, a worked example, input guidance, common mistakes and related calculators. That keeps the category useful for quick calculations while still giving enough context to verify the result.

Calculator groups in this section

Dates & Age

Age, date arithmetic and date differences.

• Age Calculator — Calculate exact age in years, months and days on a chosen date.
• Date Calculator — Add or subtract years, months, weeks and days from a date.
• Date Difference Calculator — Calculate the number of days and weeks between two calendar dates.

Time & Work Hours

Elapsed time, hours and weekly time cards.

• Time Calculator — Find elapsed time between two clock times, including overnight spans.
• Hours Calculator — Calculate decimal hours between two times after subtracting a break.
• Time Card Calculator — Total weekly work hours from daily clock-in, clock-out and break times.

How to choose the right calculator

Start with the question you are trying to answer, not just the number you already have. A focused calculator usually gives clearer inputs and a more useful result than a general-purpose tool. If your problem changes units, formula type or planning goal, follow the related-calculator links instead of reusing a tool that was built for a different purpose.

Accuracy, assumptions and rounding

Simple mathematical and unit-conversion tools follow fixed relationships. Finance, health, construction, automotive and other planning calculators may also depend on assumptions you supply. Review the method on the individual calculator page, keep units consistent, and treat estimates as planning information rather than professional advice or a guaranteed real-world outcome.

See our calculator methodology for more detail about formulas, browser-based processing, units, rounding and update practices.