About Grafolyn
Grafolyn is a free online graphing calculator. It plots functions, equations, inequalities and data, finds the values you need to full precision, and exports graphs you can actually use in a report or a worksheet. It runs entirely in your browser.
Why we built it
There are two kinds of graphing tool on the web. At one end are a handful of excellent, heavily resourced products. At the other is a long tail of sites that draw a curve and little else: no way to find a root, no way to export anything usable, and plots that join up vertical asymptotes as though they were part of the function.
Grafolyn is an attempt to build something in between: focused on doing one thing properly rather than many things adequately, and careful about the details that separate a graph you can trust from a picture of a curve.
Three of those details, concretely:
- Asymptotes break the curve. Plotting
tan(x)or1/xshould not draw a near-vertical line joining +∞ to −∞. We detect the pole and break the path, while still drawing genuinely steep functions such asx⁵unbroken. - Domain edges are found exactly.
sqrt(x)starts at the origin, not at whichever sample point happened to land near it. - Roots are distinguished from poles.
1/xchanges sign at zero but has no root there. A search based only on sign changes reports one. Ours does not.
Who it is for
Mainly students in high school and early university mathematics: algebra, precalculus, calculus and introductory statistics. It is also useful to teachers preparing worksheets, which is why the SVG export produces a real vector file with labelled axes rather than a screenshot.
You do not need an account. There is nothing to download, nothing to install and nothing to pay for.
How it works
Everything runs on your own device. When you type an expression, it is parsed and compiled into a function in your browser, then evaluated thousands of times to draw the curve. Nothing is sent to a server, because there is no server doing any of the mathematics.
That has a privacy consequence worth stating plainly: we could not see what
you are graphing even if we wanted to. Even the share links keep the graph
in the part of the URL after the #, which browsers never
transmit.
The site is built as static pages hosted on a content delivery network. The written guides contain no JavaScript at all; the graphs in them are rendered to SVG when the site is built, so they load instantly and are readable without scripts.
How it is funded
Advertising, placed in the written guides. There are no advertisements inside the calculator itself, and there will not be. Putting an ad unit next to a keypad invites accidental clicks, which is bad for the reader and dishonest towards the advertiser.
We do not charge for anything, do not sell data, and do not have a premium tier. If that changes, this page will say so.
Independence
Grafolyn is an independent project. It is not affiliated with, endorsed by, or connected to Texas Instruments Incorporated, Desmos Studio PBC, the College Board, ACT Inc., or any calculator manufacturer or examination board.
We publish reference material about the TI-84 because many students are required to use one. Referring to a product by name in order to explain how it works is ordinary descriptive use. TI-84, TI-83 and TI are trademarks of Texas Instruments Incorporated. Desmos is a trademark of Desmos Studio PBC.
About the name
Grafolyn is an invented word, chosen because it was distinctive and free of existing associations. It does not stand for anything.
Who writes this
Grafolyn is published by a small independent team working on educational tools. Content is written and reviewed against the standards set out in our editorial policy, which also explains how we handle corrections.
We would rather be corrected than be wrong. If you find a mathematical error, a broken feature, or a guide that skips a step, please tell us. Reports of incorrect mathematics are treated as urgent.
Contact
Email [email protected], or use the contact page.