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Time

Duration. SI base: the second (s).

All Time units (12)

SI base unit of time.

1/1000 second. Latency, photography.

1/1,000,000 second. Atomic physics.

1/1,000,000,000 second. CPU clock cycles.

3600 seconds or 60 minutes.

24 hours. Calendar day.

2 weeks (14 days). UK usage.

365.25 days = 31,557,600 seconds (Julian year). Calendar years differ.

Popular Time conversions

second → millisecond second → microsecond second → nanosecond second → minute second → hour second → day second → week millisecond → second millisecond → microsecond millisecond → nanosecond millisecond → minute millisecond → hour millisecond → day millisecond → week microsecond → second microsecond → millisecond microsecond → nanosecond microsecond → minute microsecond → hour microsecond → day microsecond → week nanosecond → second nanosecond → millisecond nanosecond → microsecond nanosecond → minute nanosecond → hour nanosecond → day nanosecond → week minute → second minute → millisecond minute → microsecond minute → nanosecond minute → hour minute → day minute → week hour → second hour → millisecond hour → microsecond hour → nanosecond hour → minute hour → day hour → week day → second day → millisecond day → microsecond day → nanosecond day → minute day → hour day → week week → second week → millisecond week → microsecond week → nanosecond week → minute week → hour week → day

Frequently Asked Questions

What is the SI base unit of time?

The SI base time unit is s. Most conversions factor through it, except temperature which is affine and fuel-economy which is reciprocal.

Which unit systems are represented?

Time includes both metric and imperial units (where they exist in this category). For mass and length, both metric (kg, m) and US customary (lb, ft) are listed. For temperature, the three most-common scales (Celsius, Fahrenheit, Kelvin) plus Rankine and Réaumur.

How accurate are these conversions?

Conversions use the standard SI factors (NIST values where applicable). Where two slightly different definitions exist (e.g. KB vs KiB, US vs UK gallon), they are listed as separate units rather than auto-rounded.

Other categories

Distance, height, width — anything that measures how long something is. SI base unit: the metre (m).

How much matter is in something. Differs from weight (which is force). SI base: kilogram (kg).

How hot or cold something is. Conversions are affine — there is an offset, not just a multiplier.

Size of a 2-D surface. SI base: square metre (m²).

Space occupied by a 3-D object. SI base: litre (L) for everyday use; cubic metre (m³) for SI.

Distance per unit time. SI: metre per second (m/s).

Digital information size. SI: the byte (B). Note the difference between decimal (KB=1000) and binary…

Capacity to do work. SI base: joule (J). Also commonly expressed as calories, kWh, BTU.

Force per unit area. SI base: pascal (Pa).

Rotation or turning. SI base: radian (rad).

Distance per unit of fuel, or its reciprocal (fuel per distance). Base: litres per 100 km.