Time Unit Converter

International System of Units (SI) Time Dimensions

The standard SI base unit of time is the second (s), defined by the unperturbed ground-state hyperfine transition frequency of the caesium-133 atom.

Primary Time Conversion Multipliers (to Seconds)

• Microsecond (μs): 10^-6 s = 0.000001 s

• Millisecond (ms): 10^-3 s = 0.001 s

• Minute (min): 60 s

• Hour (hr): 3,600 s

• Day (d): 86,400 s

• Week (wk): 604,800 s

• Month (mo avg): 2,629,800 s (30.4375 days)

• Julian Year (yr): 31,557,600 s (365.25 days)

• Decade: 315,576,000 s

• Century: 3,155,760,000 s

How to Use This Calculator

Enter your Time Magnitude (e.g. 86400), From (Source Unit) — choose from Seconds (s — SI Base), Minutes (min), Hours (hr), and To (Target Unit) — choose from Hours (hr), Days (d), Minutes (min). Results update instantly as you type — adjust any value to compare scenarios.

The Formula

Conversion factors (to SI base unit or reference unit):

microseconds: 0.000001

milliseconds: 0.001

seconds: 1.0

minutes: 60.0

hours: 3600.0

days: 86400.0

weeks: 604800.0

months: 2629800.0

years: 31557600.0

decades: 315576000.0

centuries: 3155760000.0

minimumFractionDigits: 2

Worked Example

86,400 seconds converts to exactly 24 hours or 1 complete calendar day.

Understanding Your Result

Unit conversion precision: round to the same number of significant figures as your original measurement. Converting 6 feet to meters gives 1.8288 m — but if your measurement was approximate (±1 inch), expressing more than 2 decimal places is false precision. For international trade and technical specifications, SI units (meters, kilograms, liters) are the standard. US customary units (feet, pounds, gallons) differ from Imperial UK units: 1 US gallon = 3.785 L vs. 1 UK gallon = 4.546 L.