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. -
Mathematical functions:
abs
,acos
,acosh
,asin
,asinh
,atan
,atan2
,atanh
,ceil
,cos
,cosh
,exp
,floor
,fromCelsius
,fromFahrenheit
,gamma
,ln
,log
,log10
,maximum
,minimum
,mean
,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 sin(30°)
-
Supported units: see Reference section below.
-
Implicit conversions:
15 km/h * 30 min
evaluates to7.5 km
. -
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:→
,➞
,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:
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
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
), ideal gas constant (R
), ... -
Last result: you can use
ans
(answer) to refer to the result of the last calculation.
-
-
User-defined functions:
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:
Syntax:
sum(<expression>, <index-variable>, <from>, <to>) product(<expression>, <index-variable>, <from>, <to>)
Examples:
# 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)
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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
,⁻¹
, ...exponentiation ^
,**
multiplication (implicit) whitespace modulo %
division per
division /
,÷
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 as50 cm / (2 m)
. -
Commands
Command Syntax help text help
,?
list of variables list
,ls
,ll
reset environment reset
clear screen clear
,cls
copy result to clipboard copy
,cp
quit (CLI) quit
,exit
-
Supported units (remember that you can use tab completion).
All SI-accepted units support metric prefixes. In addition, binary prefixes (
MiB
,GiB
, ...) are also supported.Unit Syntax Ampere amperes
,ampere
,A
Ångström angstrom
,Å
Astronomical unit AU
,au
,astronomicalunits
,astronomicalunit
Atmosphere atm
Bar bar
Barn barn
Becquerel becquerel
,Bq
Bel bel
Bit bits
,bit
Bits per second bps
British thermal unit BTU
Byte Bytes
,bytes
,Byte
,byte
,B
,Octets
,octets
,Octet
,octet
Calorie calories
,calorie
,cal
Candela candela
,cd
Coulomb coulomb
,C
Cup cups
,cup
DPI dpi
Day days
,day
,d
Degree degrees
,degree
,deg
,°
Dot dots
,dot
Electronvolt electronvolt
,eV
Euro euros
,euro
,EUR
,€
Farad farad
,F
Fluid ounce fluidounces
,fluidounce
,floz
Foot feet
,foot
,ft
Fortnight fortnights
,fortnight
Frame frames
,frame
Frames per second fps
Furlong furlongs
,furlong
Gallon gallons
,gallon
,gal
Gauss gauss
Gram grams
,gram
,grammes
,gramme
,g
Gray gray
,Gy
Hectare hectare
,ha
Henry henrys
,henries
,henry
,H
Hertz hertz
,Hz
Hogshead hogsheads
,hogshead
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
Mile miles
,mile
Miles per hour mph
Millimeter of mercury mmHg
Minute minutes
,minute
,min
Mole mole
,mol
Month months
,month
Newton newton
,N
Ohm ohms
,ohm
,Ω
Ounce ounces
,ounce
,oz
PPI ppi
Parsec parsecs
,parsec
,pc
Parts-per-million ppm
Parts-per-billion ppb
Parts-per-trillion ppt
Parts-per-quadrillion ppq
Pascal pascal
,Pa
Percent percent
,pct
Person persons
,person
,people
Piece pieces
,piece
Pint pints
,pint
Pixel pixels
,pixel
,px
Pound-force pound_force
,lbf
Pound pounds
,pound
,lb
Psi psi
RPM RPM
,rpm
Radian radians
,radian
,rad
Rod rods
,rod
Second seconds
,second
,sec
,s
Siemens siemens
,S
Sievert sievert
,Sv
Tablespoon tablespoons
,tablespoon
,tbsp
Teaspoon teaspoons
,teaspoon
,tsp
Tesla tesla
,T
Thou thou
,mils
,mil
Tonne tonnes
,tonne
,tons
,ton
,t
US Dollar dollars
,dollar
,USD
,$
Volt volts
,volt
,V
Watt-hour Wh
Watt watts
,watt
,W
Weber weber
,Wb
Week weeks
,week
Yard yards
,yard
,yd
Year years
,year
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):
-
fromCelsius
takes 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
-
toCelsius
takes 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
-
-
Why is
1/2 x
parsed as1/(2x)
?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 m
as(50 cm) / (2 m)
. If you meant ½ · x, write1/2 * 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
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What is the relation between the units
RPM
,rad/s
,deg/s
andHz
?The unit
RPM
(revolutions per minute) is defined via1 RPM = 1 / minute
where the1
on the right hand side symbolizes "1 revolution".As the base unit is the same (
1 / second
),RPM
can be converted torad / s
,deg / s
orHz
. Note, however, that1 RPM
does not equal2π rad / min
or360° / min
or1 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 by2π rad
or360 °
because: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
prefix
directory
and call 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
On Fedora 28+, you can install insect
from the official sources:
sudo dnf install insect
For Fedora versions 26 and 27, you need to enable this copr repository:
sudo dnf copr enable fnux/insect
For macOS, there is a Homebrew package:
brew install insect
For Android, install Termux from Google Play or F-Droid.
Install nodejs in Termux and then 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
npm test