Compare / GraphPad Prism

Dioptra vs GraphPad Prism

Dioptra is a free, open-source alternative to GraphPad Prism for Linux, Windows and macOS. It covers the common Prism work: tables, t tests, ANOVA, curve fitting, survival and publication graphs. Prism has decades of polish and a larger analysis library; Dioptra is free, runs on Linux, and puts effect sizes and formulas in the base product.

01 Side by side

Feature comparison

	Dioptra 0.4	GraphPad Prism 11
Price	Free, MIT licence; optional Lab license from $49 a year	$260 a year academic, $520 corporate, $142 student [1]
Linux	AppImage, deb and rpm	No; GraphPad has no plans for Linux and does not support Wine [2]
Windows and macOS	Yes, the same features and the same exported bytes on both	Yes; some import and export features are Windows-only [3]
Effect sizes for ANOVA (η², partial η², Cohen's f)	Every results sheet	Pro and Enterprise plans [4]
Formulas in the data table	Column and cell formulas in every table kind	Since Prism 11, Multiple variables tables, Pro and Enterprise plans [4]
Assumption checks	Run with the test and shown first on the results sheet	Analysis checklists in the guide, read beside the results [5]
Estimation plots	Two-group, paired and multi-group, bootstrap CIs	t tests only [6]
Analysis library	Twenty analyses, from t tests to nonlinear regression, survival, ROC and PCA	Much larger: mixed-effects models for repeated measures with missing values [7], three-way ANOVA, multiple and logistic regression, and more
Nonlinear regression	Equation library, shared parameters, constraints, F test and AICc comparison, ROUT, profile CIs	Larger equation library, refined over decades [8]
Graph editing	Graph editor with sizes in mm and points; 23 families	Decades of polish and a very large user base
Export	SVG with real text, PDF with embedded fonts, PNG; identical on every system	Many formats; EPS text and fonts need workarounds for Illustrator [9]
File format	`.dioptra`: documented JSON in a zip, diffable	`.pzfx` analyses and graphs unreadable outside Prism; `.prism` without a published schema [10]
Prism files	Opens the data tables in `.pzfx` and `.prism` files	Native
Command line	`dioptra` runs, renders and exports a project	Scripting automates import and export; the analysis lives in the file [11]
Site licenses	Department $990, institution $2,900 a year (Lab)	Not offered [12]
Support and documentation	Manual and GitHub issues; priority email with Lab	Statistics and curve-fitting guides that teach the reasoning; commercial support

A dot marks the stronger side of a row, where there is one.

Prism facts are from GraphPad's own pages, numbered below, as of October 2026.

02 In short

Which to use

Prism is the better choice when

you need an analysis Dioptra does not have, such as mixed-effects models, three-way ANOVA, multiple or logistic regression;
your lab's templates, methods and years of files live in Prism and work well;
you want commercial support and GraphPad's statistics guides at hand.

Dioptra is the better choice when

you need a free GraphPad Prism alternative, for a course, a thesis, or a lab whose license was not renewed;
you work on Linux, where Prism does not run;
you want effect sizes, formulas and assumption checks without a higher plan;
you want an open file you can inspect, diff and re-run from the command line.

Moving from Prism

Open a .pzfx or .prism file and Dioptra reads its data tables, with replicates, row titles and exclusions. Analyses and graphs are rebuilt in Dioptra: Prism encrypts those parts of its files. The table kinds have the same names as Prism's, so the layout carries over. Reading Prism files is free and stays free.

03 Prism on Linux

Running Prism work on Linux

GraphPad does not make Prism for Linux and does not support it under Wine [2]. Dioptra is built and tested on Linux first, and ships an AppImage for any distribution, a .deb for Debian and Ubuntu and an .rpm for Fedora and openSUSE. The same project file and the same exported figure come out byte for byte on Windows and macOS, so a Linux user and a Mac user in the same lab can share files.

04 Sources

Sources

Try it on your own data

Dioptra is free for any use, with no account. Install it next to what you use now and run one experiment through both.

Download Dioptra Read the ten-minute start