PureScript CSS HTML JavaScript
Latest commit dde266b Jul 2, 2017 @sharkdp Bump version to 4.8.0



A high precision scientific calculator with full support for physical units.


  • Evaluate mathematical expressions:

    sqrt(1.4^2 + 1.5^2) * cos(pi/3)^2
    • Operators: addition (+), subtraction (-), multiplication (*, ·, ×), division (/, ÷, per), exponentiation (^, **). Full list: see Reference below.

    • Mathematical functions: acos, acosh, asin, asinh, atan, atanh, ceil, cos, cosh, exp, floor, fromCelsius, fromFahrenheit, gamma, ln, log, log10, round, sin, sinh, sqrt, tan, tanh, toCelsius, toFahrenheit.

    • High-precision numeric type with 30 significant digits that can handle very large (or small) exponents like 10^(10^10).

    • Exponential notation: 6.022e23.

  • Physical units: parsing and handling, including metric prefixes:

    2 min + 30 s
    40 kg * 9.8 m/s^2 * 150 cm
    • Supported units: see Reference section below.

    • Implicit conversions: 15 km/h * 30 min evaluates to 7.5 km.

    • Useful error messages:

      > 2 watts + 4 newton meter
      Unification error:
        Cannot convert unit N·m (base units: kg·m²·s⁻²)
                    to unit W (base units: kg·m²·s⁻³)
  • Explicit unit conversions: the -> conversion operator (aliases: , , to):

    60 mph -> m/s
    500 km/day -> km/h
    1 mrad -> degree
    52 weeks -> days
    5 in + 2 ft -> cm
    atan(30 cm / 2 m) -> degree
    6 Mbit/s * 1.5 h -> GB
  • Variable assignments:

    r = 6000km
    vol = 4/3 * pi * r^3
    density = 5 g/cm^3
    vol * density -> kg
    len = 20 cm
    2pi*sqrt(len/g0) -> ms
    • Predefined constants (type list to see them all): speed of light (c), Planck's constant (h_bar), electron mass (electronMass), elementary charge (elementaryCharge), magnetic constant (µ0), electric constant (eps0), Bohr magneton (µ_B), Avogadro's constant (N_A), Boltzmann constant (k_B), gravitational acceleration (g0), ...

    • Last result: you can use ans (answer) to refer to the result of the last calculation.

  • Unicode support:

    λ = 2 × 300 µm
    ν = c/λ → GHz
  • And more: tab completion, command history (arrow keys, Ctrl+R), pretty printing, syntax highlighting, ...


  • Operators (ordered by precedence: high to low)

    Operator Syntax
    factorial !
    square/cube ²/³
    exponentiation ^, **
    multiplication (implicit) whitespace
    division /, ÷, per
    multiplication (explicit) *, ·, ×
    subtraction -
    addition +
    unit conversion ->, , , to
    assignment =

    Note that implicit multiplication has a higher precedence than division, i.e. 50 cm / 2 m will be parsed as 50 cm / (2 m).

  • Commands

    Command Syntax
    help text help, ?
    list of variables list, ls, ll
    reset environment reset
    clear screen clear, cls
    quit (CLI) quit, exit
  • Supported units (remember that you can use tab completion). All SI-accepted units support metric prefixes.

    Unit Syntax
    Ampere amperes, ampere, A
    Ångström angstrom, Å
    Astronomical unit AU
    Bar bar
    Barn barn
    Becquerel becquerel, Bq
    Bel bel
    Bits per second bps
    Bit bits, bit
    Byte Bytes, bytes, Byte, byte, B, Octets, octets, Octet, octet
    Calorie calories, calorie, cal
    Candela candela, cd
    Coulomb coulomb, C
    Cup cups, cup
    Day days, day, d
    Degree degrees, degree, deg, °
    Electronvolt electronvolt, eV
    Farad farad, F
    Fortnight fortnights, fortnight
    Fluid ounce fluidounces, fluidounce, floz
    Furlong furlongs, furlong
    Foot feet, foot, ft
    Gallon gallons, gallon, gal
    Gauss gauss
    Gram grams, gram, grammes, gramme, g
    Gray gray, Gy
    Hectare hectare, ha
    Henry henry, H
    Hertz hertz, Hz
    Hour hours, hour, h
    Inch inches, inch, in
    Joule joules, joule, J
    Katal katal, kat
    Kelvin kelvin, K
    Light-year lightyears, lightyear, ly
    Liter liters, liter, litres, litre, L, l
    Lumen lumen, lm
    Lux lux, lx
    Meter meters, meter, metres, metre, m
    Miles per hour mph
    Mile miles, mile
    Minute minutes, minute, min
    Mole mole, mol
    Month months, month
    Newton newton, N
    Ohm ohms, ohm, Ω
    Ounce ounces, ounce, oz
    Parsec parsecs, parsec, pc
    Pascal pascal, Pa
    Pint pints, pint
    Pound pounds, pound, lb
    RPM RPM, rpm
    Radian radians, radian, rad
    Second seconds, second, sec, s
    Siemens siemens, S
    Sievert sievert, Sv
    Tablespoon tablespoons, tablespoon, tbsp
    Teaspoon teaspoons, teaspoon, tsp
    Tesla tesla, T
    Tonne tonnes, tonne, tons, ton, t
    Volt volts, volt, V
    Watt watts, watt, W
    Watt-hour Wh
    Weber weber, Wb
    Week weeks, week
    Yard yards, yard, yd
    Year years, year

Install terminal version

In addition to the web interface, there is also a command line version which can by installed via npm:

npm install -g insect

For Arch Linux, there is a package on AUR:

yaourt -S insect

For macOS, there is a Homebrew package:

brew install insect


Insect is written in PureScript (see Getting Started guide). You can install all dependencies and build the whole project by running:

bower install
npm install
pulp -w browserify --skip-entry-point -m Insect --standalone Insect -O -t insect.js

Insect comes with a comprehensive set of unit tests. You can run them by calling

pulp test