Desmos Graphing Calculator

Review by eFreeware

If you regularly deal with functions, data or geometry on a screen, the Desmos Graphing Calculator is worth knowing about. It is a free Android app from Desmos Inc in the Education category, and it has been around long enough to gather more than 10 million installs and a 4.6 average from over 36,000 ratings. The people most likely to want it are students working through algebra, trigonometry or calculus, teachers who need to show a graph to a class, and anyone in engineering or science who wants a quick way to see what an equation looks like.

What it gives them is a plotting tool that covers the ground a handheld graphing calculator covers, without the cost or the clunky keypad. You type an expression, and the graph appears. The app is free, carries no ads and offers no in-app purchases, so nothing interrupts the work and there is no paid tier to weigh. That combination is rare enough in education apps that it deserves a mention up front.

What you can plot, and how freely

Graphing is the core of the app, and the developer has not been stingy with it. You can work in polar, cartesian or parametric form, and there is no limit on how many expressions you put on the screen at once. That matters more than it sounds: comparing several curves side by side is how a lot of math actually gets understood, and not having to delete one graph to draw another removes a small but constant annoyance.

The other detail I like is that expressions do not have to be rearranged into y= form. If you have an equation sitting in some awkward shape, you can enter it as it stands and let the app handle the plotting. The math engine is fast enough to plot everything from basic functions to derivatives and Fourier series, a range broad enough to cover most coursework and plenty of professional work besides.

Inequalities get the same treatment, in both cartesian and polar form, which is useful for anyone shading regions or working through systems of constraints. Between the three coordinate systems and the inequality support, the plotting side of this app reaches well past what a basic scientific calculator offers.

Sliders, tables and points of interest

Sliders are the feature that turns a static graph into something you can play with. You adjust a value and watch the curve respond, which is a direct way to build a feel for how a parameter changes a function's shape. You can also animate a parameter and watch its effect unfold across the graph, which is the sort of thing that works well when you are explaining a transformation to someone else rather than just solving a problem yourself.

Tables cover the data side. You can enter a set of values and plot them, or generate an input-output table for a function you have already defined. From there the statistics tools will fit a line, a parabola or another curve to your data, which covers a lot of what introductory statistics and lab work require.

Finding features on a curve is handled by touch. Tap a curve and the app marks its maximums, minimums and intersection points; tap one of those gray markers to read off its coordinates. If you would rather trace the curve by hand, holding and dragging along it shows the coordinates changing under your finger. Zooming is done by pinching, and you can scale the axes together or one at a time, or set the window size by hand when you need an exact view.

There is a scientific calculator mode as well. Type in an equation you want solved and the app returns the answer, handling square roots, logarithms, absolute values and similar operations. It is not the headline feature, but it means you do not have to leave the app for routine calculation.

What it asks of you

The requirements here are unusually light. The app is free, it shows no ads, and there are no in-app purchases, so there is no subscription to manage and nothing to unlock. The developer also states that no internet access is required, which means the graphing, tables and calculator work away from a connection.

The cost is in learning where things are. A graphing calculator of any kind rewards a little patience at the start, and this one is no exception: the touch interactions for points of interest and the window controls take a few tries before they feel natural. That is a small one-time investment rather than an ongoing one, and it is the only real price of entry I can see.

The app is rated for Everyone and sits in the Education category, so there is nothing here that needs supervising. It runs on Android, and the version currently listed has been updated recently with bug fixes and performance improvements.

Getting useful work out of it

The way to get the most from this app is to treat the graph as something you manipulate rather than something you look at. If you are studying transformations, set up a slider for each parameter and animate them one at a time; seeing a curve stretch and shift as a number changes does more for intuition than reading about it. If you are checking homework, plot both sides of an equation and look at where they meet.

For data work, enter your measurements into a table first and let the statistics tools suggest a fit, then adjust the window by hand so the interesting part of the curve fills the screen. The pinch zoom is quicker for exploring, but typing exact bounds is better when you need a graph you can read values from.

The recent update added version history for graphs, which is worth knowing if you tend to iterate: you can step back through earlier states of a graph instead of rebuilding it. The same update brought "and" and "or" to restrictions, so compound conditions on a plot are now expressible directly. Teachers preparing demonstrations and students working through a problem set will both find those additions useful.

A free graphing tool that earns its space

Desmos Graphing Calculator does one job and does it broadly: it turns equations and data into graphs you can explore by touch. The plotting covers cartesian, polar and parametric forms with no cap on the number of expressions, the sliders and tables make it interactive, and the statistics and scientific calculator modes round out the everyday needs of a math or science course. That it is free, ad-free and works without a connection makes the decision easier still.

It suits students from algebra upward, teachers who want to demonstrate a concept live, and professionals who need a quick visual check on a function or a data set. If you want a calculator that handles graphs rather than just arithmetic, this is a straightforward install; the only thing it asks in return is a few minutes spent learning its touch controls.

What's new in version 7.58.0.0

Version history for graphs, "and" and "or" in restrictions, plus bug fixes and performance improvements.