Time Converter
Convert durations between seconds, minutes, hours, days, weeks, and milliseconds. Convert between metric, US customary, and imperial units using documented conversion factors and high-precision decimal calculations.
Live Interactive Calculator
millisecond = second × 1000Popular Time Conversions
Explore dedicated guides with exact formulas, conversion factors, worked calculation steps, and quick reference tables.
Hours to Minutes
Convert Hour to Minute with exact formula and quick lookup tables.
Minutes to Seconds
Convert Minute to Second with exact formula and quick lookup tables.
Days to Hours
Convert Day to Hour with exact formula and quick lookup tables.
Seconds to Milliseconds
Convert Second to Millisecond with exact formula and quick lookup tables.
Weeks to Days
Convert Week to Day with exact formula and quick lookup tables.
Major Time Units & Definitions
Standard measurement units, measurement systems, and documented sources.
Second
sThe second is the SI base unit of time. Officially defined by taking the fixed numerical value of the caesium frequency ΔνCs, the unperturbed ground-state hyperfine transition frequency of the caesium-133 atom, to be 9,192,631,770 Hz.
Millisecond
msA metric unit equal to one-thousandth of a second (10^-3 s). Common in computing, electronics, and digital audio.
Minute
minA unit of time equal to 60 seconds. Widely accepted for use with the SI.
Hour
hA unit of time equal to 60 minutes or 3,600 seconds (1/24 of a mean solar day).
Day
dA unit of time equal to 24 hours or 86,400 seconds. Accepted for use with the SI.
Week
wkA time period equal to 7 standard days or 168 hours (604,800 seconds). Standard calendar work cycle.