A high precision scientific calculator with full support for physical units.
Try the web version here: https://insect.sh
Evaluate mathematical expressions:
1920/16*9 2^32 sqrt(1.4^2 + 1.5^2) * cos(pi/3)^2
Operators: addition (
+), subtraction (
-), multiplication (
×), division (
per), exponentiation (
**). Full list: see Reference below.
High-precision numeric type with 30 significant digits that can handle very large (or small) exponents like 10^(10^10).
Physical units: parsing and handling, including metric prefixes:
2 min + 30 s 40 kg * 9.8 m/s^2 * 150 cm sin(30°)
Supported units: see Reference section below.
15 km/h * 30 minevaluates to
Useful error messages:
> 2 watts + 4 newton meter Conversion 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:
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
Example: mass of the earth
r = 6000km vol = 4/3 * pi * r^3 density = 5 g/cm^3 vol * density -> kg
Example: oscillation period of a pendulum
len = 20 cm 2pi*sqrt(len/g0) -> ms
Predefined constants (type
listto 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), ideal gas constant (
Last result: you can use
ans(answer) to refer to the result of the last calculation.
Example: kinetic energy
kineticEnergy(mass, speed) = 0.5 * mass * speed^2 -> kJ kineticEnergy(800 kg, 120 km/h)
Example: barometric formula
P0 = 1 atm T0 = fromCelsius(15) tempGradient = 0.65 K / 100 m pressure(height) = P0 * (1 - tempGradient * height / T0)^5.255 -> hPa pressure(1500 m)
Sums and products:
sum(<expression>, <index-variable>, <from>, <to>) product(<expression>, <index-variable>, <from>, <to>)
# sum of the first ten squares sum(k^2, k, 1, 10) # the factorial of n as the product 1 × 2 × ... × n myFactorial(n) = product(k, k, 1, n)
λ = 2 × 300 µm ν = c/λ → GHz
And more: tab completion, command history (arrow keys,
R), pretty printing, syntax highlighting, ...
Operators (ordered by precedence: high to low)
Operator Syntax factorial
square, cube, ...
multiplication (implicit) whitespace modulo
Note that implicit multiplication has a higher precedence than division, i.e.
50 cm / 2 mwill be parsed as
50 cm / (2 m).
Command Syntax help text
list of variables
copy result to clipboard
Supported units (remember that you can use tab completion).
All SI-accepted units support metric prefixes. In addition, binary prefixes (
GiB, ...) are also supported.
Unit Syntax Ampere
Bits per second
British thermal unit
Frames per second
Miles per hour
Millimeter of mercury
Pros and cons
Reasons to use Insect
- Insect is open source.
- There is a web version that requires no installation.
- With both browser and terminal versions available, insect is truly cross-platform.
- Insect has first-class support for physical units, including metric and binary prefixes. While evaluating your calculation, Insect ensures that you did not accidentally make any mistakes in combining the physical quantities.
- Insect supports an interactive style with its readline-based interface. There is a saved history that can be browsed by pressing up- and down keys. The history is also searchable via Ctrl-R.
- The syntax of Insect is rather strict. The parser does not try to be "smart" on syntactically incorrect input, so there shouldn't be any surprises - and you can trust the result of your calculation. The parsed user input is always pretty-printed for a quick double-check.
- Insect is written in PureScript and therefore benefits from all the safety-guarantees that a strictly-typed functional programming language gives you.
- The source code of purescript-quantities (the underlying library for physical units) as well as the code of Insect itself is extensively tested.
Reasons to choose an alternative
- Insect is a scientific calculator. It's not a computer algebra system that solves differential equations or computes integrals. Try WolframAlpha instead.
- There is no graphical user interface with buttons for each action (x², 1/x, DEG/RAD, etc.). Qalculate! is a fantastic tool that supports both text- as well as graphical input.
- Insect supports a huge range of physical units: all SI units, all units that are accepted by SI as well as most units of the imperial and US customary systems (and many more). However, if you need something even more comprehensive, try GNU units.
- Insect is not a general-purpose programming language. You could try Frink.
- Insect does not have a special mode for hexadecimal or binary numbers (yet).
Why are Celsius and Fahrenheit not supported?
Compared to the SI unit Kelvin and in contrast to all other units, Celsius and Fahrenheit require an additive offset when converting into and from other temperature units. This additive offset leads to all kinds of ambiguities when performing calculations in these units. Adding two temperatures in Celsius, for example, is only meaningful if one of them is seen as an offset value (rather than an absolute temperature). Insect is primarily a scientific calculator (as opposed to a unit conversion tool) and therefore focuses on getting physical calculations right.
Even though °C and °F are not supported as built-in units, there are helper functions to convert to and from Celsius (and Fahrenheit):
fromCelsiustakes a scalar value that represents a temperature in Celsius and returns a corresponding temperature in Kelvin:
> fromCelsius(0) = 273.15 K > k_B * fromCelsius(23) to meV = 25.5202 meV
toCelsiustakes a temperature in Kelvin and returns a scalar value that represents the corresponding temperature in Celsius:
> toCelsius(70 K) = -203.15 > toCelsius(25 meV / k_B) = 16.963
1/2 xparsed as
Implicit multiplication (without an explicit multiplication sign) has a higher precedence than division (see operator precedence rules). This is by design, in order to parse inputs like
50 cm / 2 mas
(50 cm) / (2 m). If you meant ½ · x, write
1/2 * x.
What is the internal numerical precision?
By default, Insect shows 6 significant digits in the result of the calculation. However, the internal numerical precision is much higher (30 digits).
How does the conversion operator work?
The conversion operator
->attempts to convert the physical quantity on its left hand side to the unit of the expression on its right hand side. This means that you can write an arbitrary expression on the right hand side (but only the unit part will be extracted). For example:
# simple unit conversion: > 120 km/h -> mph = 74.5645 mi/h # expression on the right hand side: > 120 m^3 -> km * m^2 = 0.12 m²·km # convert x1 to the same unit as x2: > x1 = 50 km / h > x2 = 3 m/s -> x1 x2 = 10.8 km/h
What is the relation between the units
RPM(revolutions per minute) is defined via
1 RPM = 1 / minutewhere the
1on the right hand side symbolizes "1 revolution".
As the base unit is the same (
1 / second),
RPMcan be converted to
rad / s,
deg / sor
Hz. Note, however, that
1 RPMdoes not equal
2π rad / minor
360° / minor
1 Hz, as some might expect. If you interested in computing the traversed angle of something that rotates with a given number of revolutions per minute, you need to multiply by
1 RPM · (360°/revolution) = (1 revolution / minute) · (360° / revolution) = 360° / minute
In addition to the web interface, there is also a command line version which can by installed via npm:
npm install -g insect
Note that this might fail if you run it with
sudo. Instead, set up a
npm install as a user.
If you prefer not to install nodejs and npm, you can use one of the standalone binaries on the release page.
For Arch Linux, there is a package on AUR:
yaourt -S insect
For macOS, there is a Homebrew package:
brew install insect
pkg install nodejs-lts npm install -g insect
Insect is written in PureScript (see Getting Started guide). You can install all dependencies and build the whole project by running:
npm install npm start
Open web/index.html in your browser.
Insect comes with a comprehensive set of unit tests. You can run them by calling