Units
unit convert <value> <from> <to>
Description
Convert a value from a unit to another unit of the same quantity
Convert a value from a unit to another unit of the same quantity
Parameters
value: The value - Number - required
from: The unit of the value - String - required
to: The target unit - String - required
value: The value - Number - required
from: The unit of the value - String - required
to: The target unit - String - required
admin
unit convert 100 "km/h" "m/s"
mentdb
27.7777777777778
admin
unit convert 100 degC degF
mentdb
212
Temperature
admin
unit convert 37 "degC" "degF"
mentdb
98.6
Pressure
admin
unit convert 1 "atm" "Pa"
mentdb
101325
Energy
admin
unit convert 1 "kWh" "J"
mentdb
3600000
Data
admin
unit convert 1 "GiB" "MB"
mentdb
1073.741824
Length: miles to km
admin
unit convert 26.2 "mi" "km"
mentdb
42.1648128
Speed: knots to km/h
admin
unit convert 20 "kn" "km/h"
mentdb
37.04
Temperature: kelvin to degC
admin
unit convert 300 "K" "degC"
mentdb
26.85
Angle: degrees to radians
admin
unit convert 180 "deg" "rad"
mentdb
3.14159265358979
Energy: calories to joules
admin
unit convert 250 "kcal" "kJ"
mentdb
1046
Pressure: bar to psi
admin
unit convert 2.2 "bar" "psi"
mentdb
31.908302300646
Not the same quantity: error
admin
unit convert 1 "m" "kg"
mentdb
Sorry, an error appears (incompatible units: m (length) and kg (mass)).
unit calc <expression>
Description
Compute an expression with units (the result in SI units: N, J, W, Pa, V, ohm... when they match; display format: session variable [_format], as math calc). The units follow the numbers (3 m, 9.81 m/s^2, 2 kohm); a number followed by its unit binds first: 3 m / 2 s = (3 m)/(2 s). Functions: sqrt, abs, sin, cos, tan (angle in rad or deg), exp, ln, log10... Constants: _c, _h, _k, _NA, _G, _e, _me, _R... with their unit (see 'const list'). Variables: [m] (number or quantity: -> "[v]" "3 m/s"). Adding m and s is an error. degC and degF (offset) can only be converted alone: use K in the computations
Compute an expression with units (the result in SI units: N, J, W, Pa, V, ohm... when they match; display format: session variable [_format], as math calc). The units follow the numbers (3 m, 9.81 m/s^2, 2 kohm); a number followed by its unit binds first: 3 m / 2 s = (3 m)/(2 s). Functions: sqrt, abs, sin, cos, tan (angle in rad or deg), exp, ln, log10... Constants: _c, _h, _k, _NA, _G, _e, _me, _R... with their unit (see 'const list'). Variables: [m] (number or quantity: -> "[v]" "3 m/s"). Adding m and s is an error. degC and degF (offset) can only be converted alone: use K in the computations
Parameters
expression: The expression with units (ex: "230 V * 10 A", "_h*_c/(500 nm)", "[m]*9.81 m/s^2") - String - required
expression: The expression with units (ex: "230 V * 10 A", "_h*_c/(500 nm)", "[m]*9.81 m/s^2") - String - required
admin
unit calc "3 m / 2 s"
mentdb
1.5 m/s
admin
unit calc "_NA*_k"
mentdb
8.31446261815324 J/(K*mol)
Power of a resistor P = U^2 / R
admin
unit calc "(12 V)^2 / (4 ohm)"
mentdb
36 W
Force of gravity on 75 kg
admin
unit calc "75 kg * _g0"
mentdb
735.49875 N
Kinetic energy
admin
unit calc "0.5 * 1200 kg * (100 km/h)^2"
mentdb
462962.962962963 J
Ideal gas: volume of 1 mol at 0 degC and 1 atm
admin
unit calc "1 mol * _R * 273.15 K / (1 atm)"
mentdb
0.0224139695450141 m^3
Energy of a battery of 2000 mAh at 3.7 V
admin
unit calc "2000 mAh * 3.7 V"
mentdb
26640 J
Density in kg/m3
admin
unit calc "2.5 kg / (1 L)"
mentdb
2500 kg/m^3
Speed of a wave: lambda f
admin
unit calc "0.5 m * 440 Hz"
mentdb
220 m/s
Ohm law U = R I
admin
unit calc "4.7 kohm * 2 mA"
mentdb
9.4 V
Pressure under 10 m of water
admin
unit calc "1000 kg/m^3 * _g0 * 10 m"
mentdb
98066.5 Pa
Inconsistent units: error
admin
unit calc "3 m + 2 s"
mentdb
Sorry, an error appears (cannot add m and s (position 10 in '3 m + 2 s')).
unit calc <expression> <unit>
Description
Compute an expression with units and give the result as a number in the target unit (the dimensions must match)
Compute an expression with units and give the result as a number in the target unit (the dimensions must match)
Parameters
expression: The expression with units (ex: "5 V / 2 kohm", "25 degC") - String - required
unit: The target unit (ex: "mA", "km/h", "MeV", "degF") - String - required
expression: The expression with units (ex: "5 V / 2 kohm", "25 degC") - String - required
unit: The target unit (ex: "mA", "km/h", "MeV", "degF") - String - required
admin
unit calc "_h*_c/(500 nm)" "eV"
mentdb
2.47968396866401
admin
unit calc "60 W * 2 h" "kWh"
mentdb
0.12
Volume of 1 mol of ideal gas in L
admin
unit calc "1 mol * _R * 273.15 K / (1 atm)" "L"
mentdb
22.4139695450141
Wavelength of a photon of 2 eV in nm
admin
unit calc "_h*_c/(2 eV)" "nm"
mentdb
619.920992166001
Consumption: 6 L/100 km in miles per gallon (inverse)
admin
unit calc "100 km / (6 L)" "mi/gal"
mentdb
39.2024305555556
Body temperature
admin
unit calc "98.6 degF" "degC"
mentdb
37
Speed in km/h
admin
unit calc "100 m / (9.58 s)" "km/h"
mentdb
37.5782881002088
Energy of a battery in kWh
admin
unit calc "75 Ah * 12 V" "kWh"
mentdb
0.9
Power of a car in hp
admin
unit calc "110 kW" "hp"
mentdb
147.512429855453
Wavelength of a radio at 100 MHz
admin
unit calc "_c / (100 MHz)" "m"
mentdb
2.99792458
Units not compatible: error
admin
unit calc "3 m" "kg"
mentdb
Sorry, an error appears (incompatible units: the result is in m, not in kg).
Worked example: Computing with units (unit calc checks the dimensions and gives the result in SI units, or in the unit asked.)
admin
#Worked example: Computing with units; #Kinetic energy of a car of 1.2 t at 90 km/h; unit calc "0.5 * 1.2 t * (90 km/h)^2" "kJ"; #Energy of a photon of 532 nm in eV; unit calc "_h*_c/(532 nm)" "eV"; #Current in a resistor of 2.2 kohm under 5 V; unit calc "5 V / 2.2 kohm" "mA"; #Pressure of 2 mol of gas in 10 L at 25 degC (ideal gas); unit calc "2 mol * _R * 298.15 K / (10 L)" "bar";
mentdb
4.95791405920478
unit list
Description
List the quantities and their units (JSON object)
List the quantities and their units (JSON object)
admin
unit list
mentdb
{ "length": ["m", "km", "cm", "mm", "um", "nm", "pm", "angstrom", "in", "ft", "yd", "mi", "nmi", "au", "ly", "pc"], ... }
unit list <quantity>
Description
List the units of a quantity with their factor to the SI unit (and the offset for the temperatures)
List the units of a quantity with their factor to the SI unit (and the offset for the temperatures)
Parameters
quantity: The quantity (length, mass, time, temperature, area, volume, speed, force, energy, power, pressure, angle, frequency, data) - String - required
quantity: The quantity (length, mass, time, temperature, area, volume, speed, force, energy, power, pressure, angle, frequency, data) - String - required
admin
unit list "temperature"
mentdb
{"quantity": "temperature", "si": "K", "units": [ {"unit": "K", "name": "kelvin", "to_si": 1}, ... ]}
Units of pressure
admin
unit list "pressure"
mentdb
{"quantity": "pressure", "si": "Pa", "units": [ {"unit": "Pa", "name": "pascal", "to_si": 1}, {"unit": "hPa", "name": "hectopascal", "to_si": 100}, {"unit": "kPa", "name": "kilopascal", "to_si": 1000}, {"unit": "MPa", "name": "megapascal", "to_si": 1000000}, {"unit": "bar", "name": "bar", "to_si": 100000}, {"unit": "mbar", "name": "millibar", "to_si": 100}, {"unit": "atm", "name": "standard atmosphere", "to_si": 101325}, {"unit": "mmHg", "name": "millimetre of mercury", "to_si": 133.322387415}, {"unit": "torr", "name": "torr", "to_si": 133.322368421053}, {"unit": "psi", "name": "pound per square inch", "to_si": 6894.75729316836}, {"unit": "inHg", "name": "inch of mercury", "to_si": 3386.389} ]}
Units of energy
admin
unit list "energy"
mentdb
{"quantity": "energy", "si": "J", "units": [ {"unit": "J", "name": "joule", "to_si": 1}, {"unit": "mJ", "name": "millijoule", "to_si": 0.001}, {"unit": "kJ", "name": "kilojoule", "to_si": 1000}, {"unit": "MJ", "name": "megajoule", "to_si": 1000000}, {"unit": "eV", "name": "electronvolt", "to_si": 1.602176634E-19}, {"unit": "keV", "name": "kiloelectronvolt", "to_si": 1.602176634E-16}, {"unit": "MeV", "name": "megaelectronvolt", "to_si": 1.602176634E-13}, {"unit": "GeV", "name": "gigaelectronvolt", "to_si": 1.602176634E-10}, {"unit": "cal", "name": "calorie (thermochemical)", "to_si": 4.184}, {"unit": "kcal", "name": "kilocalorie (thermochemical)", "to_si": 4184}, {"unit": "Wh", "name": "watt-hour", "to_si": 3600}, {"unit": "kWh", "name": "kilowatt-hour", "to_si": 3600000}, {"unit": "MWh", "name": "megawatt-hour", "to_si": 3600000000}, {"unit": "BTU", "name": "British thermal unit (IT)", "to_si": 1055.05585262}, {"unit": "erg", "name": "erg", "to_si": 0.0000001} ]}
Unknown quantity: error
admin
unit list "foo"
mentdb
Sorry, an error appears (unknown quantity 'foo' (length, mass, time, temperature, area, volume, speed, force, energy, power, pressure, angle, frequency, data)).
unit prefix <value> <from> <to>
Description
Change the SI prefix of a value (exact): Q R Y Z E P T G M k h da none d c m u n p f a z y r q (case sensitive; the micro sign is also accepted for u)
Change the SI prefix of a value (exact): Q R Y Z E P T G M k h da none d c m u n p f a z y r q (case sensitive; the micro sign is also accepted for u)
Parameters
value: The value - Number - required
from: The prefix of the value - String - required
to: The target prefix - String - required
value: The value - Number - required
from: The prefix of the value - String - required
to: The target prefix - String - required
admin
unit prefix 1500 k M
mentdb
1.5
admin
unit prefix 2.5 G none
mentdb
2500000000
Nanometers to meters
admin
unit prefix 532 n none
mentdb
0.000000532
Kilo to milli
admin
unit prefix 2.5 k m
mentdb
2500000
Micro to nano
admin
unit prefix 0.47 u n
mentdb
470
Without prefix to mega
admin
unit prefix 2500000 none M
mentdb
2.5