Add hours and minutes to any time — shift schedules, compute end times, total durations. Add 8h30m to 9:00 for shift end — free, local, no signup.
Calculate total work hours for a single shift between start and end times with one configurable break. Essential for timesheets and payroll. Numbers never leave your device — every calculation runs locally in your browser.
Add and subtract hours:minutes durations — timesheets, shifts, project totals. Sum 7:30 + 8:15 correctly — free, local, no signup.
Calculate the exact duration between two times. Handles overnight time spans and displays results in hours, minutes, and seconds. Numbers never leave your device — every calculation runs locally in your browser.
Estimate password crack times from length, charset, and attacker speed — entropy made visceral. Show why 8-char passwords fall in hours — local math, free, no signup.
Convert between time units including seconds, minutes, hours, days, weeks, months, and years with precise decimal results. Input never leaves your device — everything runs locally in your browser.
17:30 (5:30 PM) — hours add directly, minutes carry past 60. Overnight spans roll into next-day notation automatically.
Yes — chain entries: 2h15m + 1h45m + 30m totals 4h30m. Timesheets add weekly columns the same way.
Both display where relevant — 17:30 reads 5:30 PM. Roster and payroll contexts prefer 24h.
No — math runs locally in your browser. Nothing leaves your device.
Time Duration Calculator
Calculate the exact duration between two times. Handles overnight time spans and displays results in hours, minutes, and seconds. Numbers never leave your device — every calculation runs locally in your browser.
Date Addition Calculator
Add or subtract days, weeks, months, and years from any date — calendar-accurate. Find 100 days from hire date exactly — free, local, no signup.
Last updated October 2026