Calculator Guide

Compound units

Hissab understands compound units built with *, /, integer powers, and parenthesized groups. Units with the same dimensional signature can be converted even when written differently.

Forms

  • Literal compounds — 9.8 meter/second^2
  • per alias — 60 mile per hour
  • Shortcuts — mph, kph, fps, fpm, psi
  • Conversion — 60 mile/hour to kilo meter/hour
9.8 meter/second^2
60 mile/hour to meter/second
60 mile per hour to meter/second
1 newton to kilo gram*meter/second^2
1 atmosphere to pascal
5 meter^2 to square meter

Arithmetic

Multiplication and division propagate units, cancel dimensions, and can produce derived units.

60 kilo meter/hour * 2 hour
5 kilo meter / 2 meter
10 newton * 5 meter to joule
1 / (5 second) to hertz

Named derived units

  • Force — newton/N, dyne, pound force/lbf, kilogram force/kgf, kip
  • Energy — joule/J, calorie/cal, kilocalorie/kcal, BTU, electron volt/eV, erg, watt hour/Wh, kilowatt hour/kWh, foot pound, therm, ton TNT
  • Power — watt/W, horsepower/hp, metric horsepower, electrical horsepower, BTU per hour, foot pound per second
  • Pressure — pascal/Pa, bar, atmosphere/atm, psi, torr, mmHg, inHg, pound per square foot
  • Frequency — hertz/Hz, rpm
  • Speed — knot/kn, mach, speed of light, mile/hour, kilometer/hour, meter/second, feet/second
  • Acceleration — standard gravity, galileo, meter/second^2
  • Illuminance — lux/lx, foot candle, phot
  • Luminous flux — lumen/lm
  • Radioactivity — becquerel/Bq, curie/Ci
  • Radiation dose — gray/Gy, sievert/Sv, rad, rem
  • Catalytic activity — katal/kat
  • Concentration — molar, mole/liter
  • Dynamic viscosity — poise, centipoise/cP, pascal*second
  • Kinematic viscosity — stokes, centistokes/cSt, meter^2/second
  • Electromagnetism — coulomb, volt, ohm, farad, henry, weber, tesla, gauss, maxwell, oersted, siemens
  • Dimensionless multipliers — ppm, ppb, ppt
5 ppm
60 rpm to hertz
750 watt to horsepower

Worked examples

Kinetic energy for a 1500 kg car at 60 mph:

v = 60 mile/hour to meter/second
ke = (1500 kilo gram * v^2) / 2

Pressure at the bottom of a 10 meter water column:

1000 kilo gram/meter^3 * 9.8 meter/second^2 * 10 meter to pascal

Common mistakes

  • 9.8 m/s^2 and 5 m/s are invalid for meters — m means million. Write meter.
  • 5 celsius/meter is invalid — use kelvin in compound units, because Celsius and Fahrenheit are affine temperatures.
  • 5 meter^2 means five square meters. For five meters squared, write (5 meter)^2.
(5 meter)^2