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All units

Browse every unit in the Unitbox catalogue, organised by measurement category.

All units as a working topic

Browse the units, compare the pairs people use most, then open a short reference guide when the number needs context.

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所有All units单位（111）

The SI base unit of length. Defined by the speed of light since 1983.

1000 metres. Standard road distance unit.

1/100 of a metre. Common for body and clothing measurements.

1/1000 of a metre. Standard for small machined parts and rainfall.

1/1,000,000 of a metre. Cell biology, semiconductor manufacturing.

1/1,000,000,000 of a metre. Wavelength of visible light, chip feature sizes.

5,280 feet or 1,609.344 metres. Statute mile, used on road signs in the US and UK.

3 feet or 0.9144 metre. Still used in US football and some fabric sales.

12 inches or 0.3048 metre. US height, altitude in aviation.

1/12 of a foot or 25.4 mm. Screen sizes, paper, US fastener sizes.

1,852 metres. Used for marine and aviation navigation.

Distance light travels in one Julian year — about 9.46 trillion km. Astronomy.

1/10,000,000,000 metre. Spectroscopy and crystallography.

The SI base unit. Defined by Planck's constant since 2019.

1/1000 of a kilogram. Cooking and small packages.

1/1,000,000 kilogram. Medication, trace nutrients.

1000 kilograms. International freight and carbon emissions.

0.453 592 37 kg. US body weight, food packaging.

1/16 of a pound, or about 28.35 g. Cooking in the US.

14 pounds (6.35 kg). UK body weight.

Exactly 64.798 91 milligrams. Bullets, precious metals in troy.

1/1,000,000,000 kilogram. Vitamins, dosage.

200 milligrams. Gemstones.

Water freezes at 0°, boils at 100° at standard pressure.

degree Fahrenheit

Water freezes at 32°, boils at 212°. Common in the US.

Absolute temperature scale. Same size as Celsius, 0 K = absolute zero.

Fahrenheit scale starting at absolute zero. Used in US engineering.

degree Réaumur

Water freezes at 0°, boils at 80°. Historical, used in cheese.

SI base unit of area.

square kilometre

100 hectares or 1,000,000 m². Country/city size.

square centimetre

Small surfaces, cross-sections.

100 m × 100 m. Standard farm and forest area unit.

US floor area, real estate.

US small surface area.

640 acres. US county/area units.

4,047 m². US farmland and lot size.

9 ft². Carpet and fabric sales.

400/121 m² ≈ 3.305785 m². Japanese (and Korean pyeong) land/real-estate area unit.

One tatami mat. Edo-period (江戸間) standard 1.6562 m², used here.

1000 cm³. Cooking, beverages, fuel.

1 cm³. Medicine doses, perfume.

1000 L. SI unit of volume.

About 28.3 L. Refrigerators, natural gas.

Engine displacement in the US.

About 3.79 L. US fuel.

About 4.55 L. Imperial units.

1/2 US quart, 16 fl oz.

8 fl oz, 16 tbsp. US cooking.

1/128 US gallon. Beverages.

1/2 fl oz, 3 tsp. Cooking.

1/3 tbsp. Spices, baking.

barrel (petroleum)

42 US gallons. Crude oil benchmark.

metre per second

SI unit of speed.

kilometre per hour

1 km per hour. International road speed.

US and UK road speed.

1 nautical mile per hour. Marine and aviation.

foot per second

Ballistics and engineering in the US.

Speed of sound (~340 m/s at sea level). Aviation.

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.

One binary digit — 1/8 byte. Networking.

8 bits. Standard unit of digital storage.

1000 bytes (decimal). Disk marketing.

1024 bytes (binary). RAM.

10⁶ bytes (decimal).

1024 KiB (binary). RAM.

10⁹ bytes (decimal). SSDs, downloads.

10¹² bytes (decimal). Hard drives.

10¹⁵ bytes. Data centres.

kilobit per second

1000 bits per second. Internet speeds.

SI unit of energy. 1 N·m.

1000 J. Food labels in some countries.

4.184 J. The energy to heat 1 g water by 1 °C.

1000 calories (4.184 kJ). Food labels in the US.

1 W sustained for 1 hour (3600 J).

1000 Wh. Electricity bills.

British thermal unit

≈ 1055 J. HVAC in the US.

Energy of 1 e⁻ accelerated through 1 V. Particle physics.

Energy to lift 1 lb by 1 ft. Torque, firearms.

100,000 BTU. Natural gas billing.

1 N/m². SI unit of pressure.

1000 Pa. Tire pressure (typical).

100,000 Pa. Diving, hydraulics.

100 Pa. Meteorology.

pound per square inch

About 6.9 kPa. US tire pressure, plumbing.

Standard atmospheric pressure at sea level.

1/760 atmosphere. Vacuum.

millimetre of mercury

Traditional blood pressure unit.

1/360 of a full turn. Compass, latitude.

The angle subtended by an arc equal to the radius. SI unit.

1/400 of a turn. Surveying.

1/3600 degree. Astronomy.

One full rotation.

US miles per gallon

Miles per US gallon. Converted via L/100 km as base.

UK miles per gallon

Miles per imperial gallon.

litre per 100 km

Standard fuel consumption metric (EU, China). Lower is better.

kilometre per litre

Distance per litre of fuel. Higher is better.

Frequently Asked Questions

What is the SI base unit of all units?

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

Which unit systems are represented?

All units 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.

其他分类

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).

Duration. SI base: the second (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.