Desmos (desmos.com) is a free collection of browser-based math tools built around one everyday problem: you need a graphing calculator and do not have one. Open https://www.desmos.com/calculator, type a function, inequality or equation, and the curve appears immediately — no install, no sign-up. The site is run by Desmos Studio, which split off from the original Desmos company in 2022 as a Public Benefit Corporation with the stated goal of helping everyone learn math, love math, and grow with math; its free tools are used annually by more than 75 million people worldwide (About, checked 2026-08-31). Compared with other free calculators, its verifiable distinctions are that all seven tools are free with no advertising, the calculators are embedded in the majority of U.S. state-level assessments and digital college entrance exams, and accessibility (screen readers, braille, audio tracing) is treated as a first-class product capability.

The Desmos graphing calculator: three expressions with parameter sliders on the left, live curves on the right

At a Glance

  • URL: https://www.desmos.com/
  • Type: Online math calculation and visualization tools (graphing, geometry, scientific, matrix, 3D, Notebook)
  • Cost: All calculator tools are free and ad-free; paid offerings are commercial API licensing and the team plan Desmos Professional ($8 per seat/month during early access)
  • Account: Every tool works without an account; a free account is required only to save graphs and notebooks
  • Interface languages: 20 languages, including French, German, Japanese, Korean, Spanish, and Simplified and Traditional Chinese

Background

Desmos was founded by Eli Luberoff, and the graphing calculator was unveiled at TechCrunch Disrupt New York in 2011 (Wikipedia: Desmos, checked 2026-08-31). In May 2022 the company split in two: the curriculum and classroom-activity business (Desmos Classroom, formerly teacher.desmos.com) was sold to the education company Amplify, while the calculators stayed with the independently operated Desmos Studio PBC, which promised in its announcement that "everything that is free will remain free, now and always".

Today desmos.com keeps only the math tools, Help Center, accessibility pages and API documentation; the teacher-created classroom activities left the site together with Desmos Classroom and now live on Amplify Classroom (checked 2026-08-31). Desmos Studio earns revenue from partnerships with "the world's most popular curricula and learning software" and with most U.S. state-level assessments and digital college entrance exams (About), plus commercial API and team subscriptions — not from charging calculator users or showing ads.

What the Tools Do

The graphing calculator is the heart of the site: enter functions, equations, inequalities or tables of data line by line in an expression list and the coordinate plane updates live. Undefined parameters (such as a and b in y=a sin(bx)) automatically become sliders, so you can watch what each parameter does to the curve. Regression fitting, function definitions, animation and coloring are built in, and the tool is widely used for graph-art creations. Finished graphs export as PNG or SVG, or generate HTML embed code (Help Center: Saving and Sharing).

Seven tools cover different math scenarios, each reachable from the homepage:

  • Graphing Calculator: function plotting and data visualization
  • Geometry Tool: construct points, lines, circles and polygons and measure them; the construction is recorded on the left as expressions such as polygon(A, B, C, D, E)
  • Scientific and Four-Function calculators: keypad-driven fraction, trigonometry and statistics work
  • Matrix Calculator: vector and matrix operations
  • 3D Calculator: plot surfaces, curves and points in space by entering z=f(x,y)
  • Notebook (beta): combine text, 2D graphs, 3D graphs and sliders in one document

The Geometry Tool: construction tools on the left, a pentagon on the canvas, and the expression polygon(A,B,C,D,E) in the list

The Scientific Calculator: a virtual keypad at the bottom, with sin(pi/6)+sqrt(2)^2*3! evaluated above it

The 3D Calculator rendering the surface z=sin(x)cos(y)

Saving and sharing: everything calculates without logging in. Pressing Save prompts you to sign in or create a free account, after which graphs can be saved, renamed, organized into folders and kept with version history. Sharing comes in three forms: a snapshot link (read-only, frozen at the current state), a saved share link that keeps updating as you edit, and image export; recipients can save their own copy without touching the original (Help Center).

Accessibility

Accessibility is an explicitly stated design priority. Desmos states that its website and all math tools conform to WCAG 2.2, and the calculators support audio tracing (tone changes that follow a curve), screen readers and braille output. The accessibility page provides detailed setup guides for six screen readers — JAWS, NVDA, Narrator, VoiceOver (Mac/iOS), TalkBack and ChromeVox — and graphs can be exported to a braille embosser (checked 2026-08-31).

Accounts and Open Capabilities

A free account exists to save graphs and notebooks across devices; day-to-day use and snapshot sharing require no login. For developers, the Desmos API (currently v1.12) embeds the calculators in your own pages and apps; registering a free API key is enough to start, and the API documentation lists 20 interface languages for embedded instances. Pricing is tiered: personal and school projects are free, the Starter plan costs 100/monthfororganizationsunder100/month for organizations under100k in annual revenue, and commercial publishing or enterprise needs are quoted individually (My API, checked 2026-08-31). Under the API Terms of Service, free use must not charge end users, must show attribution near the calculator, must not obscure the Desmos logo or "powered by" label, and requires users to be 13 or older; reverse engineering, sublicensing and building a competing product are prohibited.

Copyright and Content Policy

The expressions and graphs you enter remain yours; shared public graphs can be viewed, copied and adapted by others (Help Center). The API and all content provided through it are protected by copyright and other intellectual property laws and belong to Desmos or its licensors (API Terms of Service). The classroom-activity platform is no longer part of this site; teacher and student content there is managed by Amplify.

When It Fits

  • Students and teachers plotting and analyzing functions in or out of class, especially without a handheld graphing calculator.
  • Parameter experiments, geometric constructions, matrix work or 3D surface visualization in science and math courses.
  • Teachers building interactive math demos to share by link or embed code.
  • Developers embedding Desmos calculators in education products via the API.
  • Blind and low-vision learners doing math with screen readers, braille output and audio tracing.

Limitations

  • Connection quality varies by region and some assets load slowly; the calculators offer 20 interface languages, but the Help Center and documentation are primarily English.
  • There is no offline version, and graphs live in a cloud account, so heavier use depends on network access and logging in.
  • The graphing calculator centers on mathematical expressions and offers no full document layout; papers still need LaTeX.
  • The free API tier has firm conditions (no charging users, mandatory attribution), and commercial embedding requires a paid plan.
  • The classroom-activity platform formerly part of Desmos now lives on Amplify Classroom and is no longer offered on desmos.com.

References