Just type
The result is worked out as you type. You write fractions, powers and roots exactly as on paper. No fiddly brackets.
The calculator that shows you the way.
Derivatives, systems of equations, step-by-step solutions and advanced graphing. Free, with no subscription. All in one app that is as easy to use as the calculator that came with your phone.
Simple by default
Everything clear, no manual needed.
Simple, intuitive controls. If you can handle your phone's keyboard, you will find Arithmeticus easy too. Copy and paste work exactly the way you expect.
Intuitive keypad
Everything you need for everyday calculations is on the main page. Swipe left or right for the advanced functions, and long-press a key for even more.
Follow the solution
Not sure how a result came about? Open the step-by-step solution for any calculation, with the rules and explanations.
A quick tour
The calculator for school and university.
Write it the way you would on paper.
Fractions, powers, roots, integrals and matrices appear in proper notation right away. Calculate with units and physical constants, and convert any unit into the one you need.
- Natural display
- 18 unit categories
- Constants library
- Matrices
See every step and the rule behind it.
Tap Solution to see how a result comes about. Every step names the rule that was used, for equations, systems, inequalities, derivatives, integrals, limits and more.
- Equations and systems
- Inequalities
- Derivatives and integrals
- Differential equations
Graph it in 2D and 3D.
Plot functions, implicit curves, parametric lines and 3D surfaces. Points snap to zeros, extrema, inflection points and intersections, and the trace, tangent and area tools solve graphically.
- Implicit curves
- 3D surfaces
- Snap to points
- Polar and log axes
Calculus, done properly.
Derivatives at a point and partial, definite and double integrals, limits, sums, products and Taylor polynomials. Exact wherever a formula exists, numeric when there is none.
- Partial derivatives
- Double integrals
- Limits
- Taylor polynomials
Help that works offline, always.
A searchable guide explains every key and function, with examples you can put straight into the line. The function search lists every other function of the calculator with a short description.
- Function picker
- In-app guide
- Try-it examples
Everything included
The complete feature set. Everything unlocked.
No trial, no premium version, no annoying prompts. This is a tool that works from day one.
Live, exact results
The result is worked out while you type. Fractions, roots and π stay exact; switch to decimal, scientific, mixed number, polar or HEX/OCT/BIN in one tap.
8 + 2= 32
Equations and inequalities
Single equations, linear and many non-linear systems, inequalities with interval notation and a number line.
Calculus
Derivatives, antiderivatives, definite integrals, sums, products, one-sided limits and Taylor polynomials.
Differential equations
First-order linear and separable, second-order linear with constant coefficients, with or without initial conditions.
Matrices and vectors
Determinant, inverse, transpose, row reduction, eigenvalues and eigenvectors; dot and cross product, norm, angle, projection and unit vector.
eig 2112λ = 1, 3
Complex numbers
Rectangular and polar form (r∠θ), with re, im, arg and conj.
Units and constants
Calculate and convert across 18 categories, from length and pressure to energy and electricity, with metric, imperial or US results. A searchable library of physical constants comes with their units.
2 mol × R × 25 °C ÷ 1.013 bar= 0.0489 m³
Scientific functions
Trig functions with their reciprocals, hyperbolic functions and all inverses, logs to any base, factorials, Γ and n-th roots.
Function picker
Statistics, combinatorics, probability distributions, rounding, number theory and random numbers, all searchable.
Programmer mode
Hexadecimal, octal and binary input with bitwise operations and shifts.
Variables and history
Store values, matrices and vectors with :=, reuse the last result with Ans, undo deletions and save sessions to a file.
Made to fit you
English, German, French, Spanish, Russian and Simplified Chinese. Light or dark theme, point or comma as decimal separator, and a side-by-side keypad on tablets and foldables.
For students
From your first fractions to your final exams.
Start with the basics and keep it for the hard stuff. Arithmeticus grows with your courses, and the steps help you understand every answer along the way.
Check your homework and see where it went wrong.
- Fractions stay fractions13 + 16 = 12
- Solve with every step shown2x + 3 = 11
- Find zeros on the graphx2 − 4 = 0
- Convert units90 km/h = 25 m/s
The tools your lectures assume you already have.
- Eigenvalues and eigenvectorsdet(A − λI) = 0
- Differential equationsy″ + y = 0
- Taylor polynomialsex ≈ 1 + x + x22
- Partial derivatives, double integrals∂x, ∬
Check your school's or exam's rules before using any calculator app in a test.
Respectful by design
No ads. No tracking. No network access.
Your maths stays on your phone
The app does not use the internet at all. Everything is calculated on your device, so it works anywhere, even in airplane mode.
Open source, for good
Licensed under the GPL-3.0. Read the code, build it yourself or suggest changes on GitHub. It is and will stay open source.
Free. Really.
No trial, no subscription, no in-app purchases. The full feature set is yours from the first tap.
Get Arithmeticus for free.
Install it from your favourite store, or grab the APK straight from GitHub.
Requires Android 11 or newer.
♥︎ Support this app
Arithmeticus is free and stays free. If it saved you some time, or an exam, you can buy the developer a coffee.