Hours Calculator
Every calculator in the Hourglass Toolkit, in one place. Pick a tool to get started — each one runs entirely in your browser.
Time Duration Calculator
Find the exact hours, minutes, and seconds between two clock times.
Duration & CountdownDate & Time Difference Calculator
Calendar-aware elapsed time between two full dates and times.
Duration & CountdownCountdown Timer
Live countdown to any date, time, and custom label.
Duration & CountdownOnline Stopwatch
Start, pause, and lap a stopwatch accurate to the hundredth of a second.
Add & SubtractAdd / Subtract Time Calculator
Add or subtract hours, minutes, and seconds from a clock time.
Add & SubtractAdd / Subtract Date Calculator
Add or subtract years, months, weeks, and days from a date.
AgeAge Calculator
Exact age in years, months, and days, plus total days and hours lived.
ConversionsTime Unit Converter
Convert between seconds, minutes, hours, days, weeks, months, and years.
ConversionsDecimal Hours Calculator
Convert hours and minutes to decimal hours for payroll, and back.
WorkTimesheet Calculator
Total hours worked and estimated pay across multiple shifts.
World TimeTime Zone Converter
Convert a date and time between time zones, plus a live world clock.
About Hourglass Toolkit
Hourglass Toolkit is a free collection of time and date calculators covering everything from simple duration math to full time zone conversion. Every tool runs locally in your browser — no data is ever sent to a server, and no account is required.