Unit Converter (Metric system, US customary units, etc.) / Tool

How to use this tool

• Entering a value in any unit will automatically convert it to another unit.
• Rounded to the fourteenth decimal place.
• A number with many digits may appear as 1e9. This is the computer’s exponential representation, where “e” is a power of 10.
  e.g. 1e3 = 10³ = 1,000
  e.g. 1e-3 = 10^-3 = 0.001
• This tool does not check the lower limit, so even if it is less than 0 Kelvin, it will be converted without error. Please note.

Metric system

The metric system is a system of units based on the meter as a unit of length and the kilogram as a unit of mass.

Non-SI unit of length: Nautical mile

Historically, it was defined as the meridian arc length corresponding to one minute (1/60 of a degree) of latitude. Today the international nautical mile is defined as exactly 1,852 metres (6,076 ft; 1.151 mi).

$1nm = 1852m$

Non-SI units of area: Hectare / Are

One hectare is 10,000 square meters and one hectare is 100 square meters, but neither is an SI unit.

Non-SI units of volume: Liter

One liter is defined as the volume of a cube of 10 cm on each side (= 1dm³).

United States customary units / Imperial units

The United States customary units / Imperial units is a system of units used mainly in the United States, with the yard as the basic unit of length and the pound as the basic unit of mass.

In addition, different units are used in the U.S. and the U.K. for volume.

Volume of liquids (US)

※バレルは石油以外では定義が異なります。

Volume of liquids (UK)

Japanese units of measurement (shaku–kan system)

The shaku–kan system is a traditional Japanese units of measurement , with the basic unit being the shaku for length and the kan for mass.

• Length: The basic unit is the “shaku (尺)“. 1 shaku is defined as 10/33 of a meter.
• Mass: The basic unit is the “kan (貫)“. 1 kan is defined as 3.75 kg.
• Area: The basic unit is the “tsubo (坪)“. 1 tsubo is defined as 400/121 of a m².
• Volume: The basic unit is the “shō (升)“. 1 shō is defined as 2401/1331000 of a m³.

Unit of force

The unit of force in the International System of Units (SI) is the newton.

$1 N = 1 kg·m/s^2$

$1 dyn = 10^{−5} N$

$1 kgf = 9.80665 N$

$1 lbf = 4.4482216152605 N$

$1 pdl = 0.138254954376 N$

Unit of pressure

The unit of force in the International System of Units (SI) is the pascal.

$1 bar = 10^5 Pa = 100 kPa$

$1 atm = 101325 Pa$

$1 at = 98066.5 Pa$

$1 Torr = 1 mmHg = {\dfrac {1}{760}} atm = {\dfrac {101325}{760}} Pa \approx 133.322 Pa$

$1 mH_2O = 10^2 cmH_2O = 10^3 mmH_2O = 9806.65 Pa$

$1 inH_2O = {\dfrac {1}{12}} ftH_2O = 249.0899 Pa$

$1 psi = 6894.76 Pa$

Unit of energy

The unit of force in the International System of Units (SI) is the joule.

$1 erg = 10^{-7} J$

$1 cal_{th} = 4.184 J$

$1 cal_{IT} = 4.1868 J$

$1 kgf·m = 9.80665 J$

$1 ft·pdl = 0.0421401100938048 J$

$1 ft·lbf = 1.3558179483314004 J$

$1 kW·h = 3.6 \times 10^6 J = 3.6 MJ$

$1 Btu = 1055.05585262 J$

$1 eV = 1.602176634 \times 10^{−19} J$

$1 t = 4.184 \times 10^9 J$

Unit of temperature

The unit of force in the International System of Units (SI) is the kelvin.

$0 K = \text{Absolute zero}$

$[°C] = [K] - 273.15$

$[°F] = [K] \times {\dfrac {9}{5}} - 459.67$

$[°F] = [°C] \times {\dfrac {9}{5}} + 32$

$[°R] = [°K] \times {\dfrac {9}{5}}$

$[°De] = (100 - [°C]) \times {\dfrac {3}{2}}$

$[°N] = [°C] \times {\dfrac {33}{100}}$

$\text{[°Ré]} = [°C] \times {\dfrac {4}{5}}$

$\text{[°Rø]} = [°C] \times {\dfrac {21}{40}} + 7.5$

Unit of time

The unit of force in the International System of Units (SI) is the seconds.

Unit of tatami mats

Jō (帖, 畳) is a unit of measurement used to express the floor area of a room.

Jō (帖)

“畳” varies in size, but “帖” is clearly defined as 1.62 square meters.

Jō (畳)

There are multiple types of “畳” dimensions, and the area varies depending on which dimension “畳” is based on. There seem to be two reasons for the creation of multiple types.

1. The standard 1間 (ken) dimension varies from period to period and region to region.
2. Whether tatami split (based on tatami) or pillar split (based on pillar) varies by period and region.

Unit of bit/byte

$1byte = 8bit$

$1KB = 1024byte$

$1MB = 1024KB = 1024^2byte$

1 KB is 1024 Bytes? or 1000 Bytes?

This tool converts 1 kilobyte (KB) to 1024 bytes.

But originally kilo is $10^3$. These are called metric prefixes.

But since computers are binary numbers, $10^n$ is inconvenient.

$1bit = 2^1 = 2$
$2bit = 2^2 = 4$
$3bit = 2^3 = 8$
…
$8bit = 2^8 = 256$
$9bit = 2^9 = 512$
$10bit = 2^{10} = 1024$

Therefore, the computer decided as follows.

• KB: 1,024byte
• MB: 1,024KB
• GB: 1,024MB

But this conversion method is often confusing. It is recommended to use a binary prefix to ensure a distinction.