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
.
Highprecision 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 to
7.5 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.
Userdefined 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>, <indexvariable>, <from>, <to>)
product(<expression>, <indexvariable>, <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)
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 as 50 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 SIaccepted 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

Lightyear 
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

Partspermillion  ppm 
Partsperbillion  ppb 
Partspertrillion  ppt 
Partsperquadrillion  ppq 
Pascal 
pascal , Pa

Percent 
percent , pct

Person 
persons , person , people

Piece 
pieces , piece

Pint 
pints , pint

Pixel 
pixels , pixel , px

Poundforce 
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

Watthour  Wh 
Watt 
watts , watt , W

Weber 
weber , Wb

Week 
weeks , week

Yard 
yards , yard , yd

Year 
years , year

Reasons to use Insect
Reasons to choose an alternative
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 builtin 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 as 1/(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, 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
, rad/s
, deg/s
and
Hz
?
The unit
RPM
(revolutions per minute) is defined via 1 RPM = 1 / minute
where
the 1
on the right hand side symbolizes "1 revolution".
As the base unit is the same (1 / second
), RPM
can be converted
to rad / s
, deg / s
or Hz
. Note, however, that 1 RPM
does
not equal 2π rad / min
or 360° / min
or 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 2π rad
or 360 °
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 FDroid.
Install nodejs in Termux and then install insect
.
pkg install nodejslts
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