⏱️ Time Conversion

Convert between time units for project management, scheduling, science, and everyday use. Supports seconds, minutes, hours, days, weeks, months, years, decades, centuries, and milliseconds.

Time conversion calculates duration based on the international SI base second (s), standardized by BIPM/SI via 9,192,631,770 transitions of the cesium-133 atom. 1 minute equals 60 seconds, 1 hour equals 3,600 seconds, and 1 standard calendar day equals 86,400 seconds (24 hours).

Metrological Standards & Base Equation

1 hour = 60 minutes = 3,600 seconds. 1 day = 24 hours. 1 year = 365.25 days (accounting for leap years).

All temporal ratios are aligned with the BIPM International Atomic Time (TAI) and Coordinated Universal Time (UTC) definition of the SI second, established by the 13th General Conference on Weights and Measures (CGPM).

Primary References: BIPM SI Brochure (2019) · Standards Directory

Supported Time Units (13 Total)

Time Unit Definitions and Scaling Factors
Unit Symbol Unit Name System Equivalent in Second
ns Nanosecond Scientific 1 ns = 1.000000e-9 s
µs Microsecond Scientific 1 µs = 0.000001 s
ms Millisecond Scientific 1 ms = 0.001 s
s Second Scientific SI Base Unit (1 s)
min Minute Scientific 1 min = 60 s
hr Hour Scientific 1 hr = 3600 s
day Day Scientific 1 day = 86400 s
week Week Scientific 1 week = 604800 s
mo Month Scientific 1 mo = 2629800 s
yr Year Scientific 1 yr = 31557600 s
decade Decade Scientific 1 decade = 315580000 s
century Century Scientific 1 century = 3155800000 s
millennium Millennium Scientific 1 millennium = 31558000000 s

Popular Time Conversions

Hours to Minutes

h → min — scheduling & planning

Days to Hours

d → h — project timelines

Minutes to Seconds

min → s — precise timing

Weeks to Days

wk → d — work & travel planning

Years to Days

yr → d — long-term planning

Common Use Cases

  • Project management (h↔min)
  • Fitness & workouts (min↔s)
  • Travel planning (d↔h)
  • Scientific experiments (ms↔s)
  • Payroll & billing (h↔min)

Frequently Asked Questions

How many minutes in a day?

There are 1,440 minutes in a day (24 hours × 60 minutes).

How do I convert hours to seconds?

Multiply hours by 3,600. For example, 2 hours × 3,600 = 7,200 seconds.