The best Mandelbrot set explorer on the web
Mandelbro is a free, open-source Mandelbrot set rendererthat runs entirely in your browser — no downloads, no sign-up, no server round-trip. Pan with your mouse or finger, scroll to zoom, and the fractal regenerates in real time at any depth. When you cross the precision wall that limits ordinary fractal viewers at about 1014× magnification, Mandelbro automatically switches to an arbitrary-precision perturbation pipeline so you can keep zooming past 1050×.
What is the Mandelbrot set?
The Mandelbrot set is the set of complex numbersc for which the iteration zn+1 = zn2 + c(starting from z0 = 0) does not escape to infinity. Discovered by Benoît Mandelbrot in 1980, its boundary is a fractal curve of Hausdorff dimension 2 — infinitely complex, infinitely self-similar, and one of the most recognizable images in modern mathematics. Zoom in anywhere on the boundary and you will eventually find spirals, dendrites, and miniature copies of the entire set called minibrots.
How Mandelbro renders deep zoom
Naïve Mandelbrot renderers compute every pixel independently using IEEE 754 double-precision floating point, which runs out of digits at about 16 decimals. Below that — roughly 1013viewport height in the complex plane — adjacent pixels round to identical values and the image stops resolving. Mandelbro avoids this by computing one high-precision reference orbit at the view center using arbitrary-precision arithmetic, then deriving every other pixel as a fast double-precision delta from that orbit. This technique, calledperturbation theory, is combined with series approximation so early iterations can be skipped entirely. The result: smooth real-timedeep zoom in a browser tab.
Famous locations to start exploring
The Mandelbrot set has thousands of named regions, but a handful of classic deep-zoom destinations show off its diversity:
- Seahorse Valley — the famous spiral-filled gap between the main cardioid and the period-2 bulb
- Elephant Valley — trunk-and-tusk spirals along the right edge of the main cardioid
- Lightning Bolt — jagged dendrite filaments that branch like static electricity
- Double Spiral — interlocked spirals near the upper antenna — peak psychedelic territory
- Mini Mandelbrot — a miniature copy of the entire Mandelbrot set hidden along the real axis
- Starfish — five-armed radial structures with rainbow color cycling
- Jewel — a tightly faceted gem-like cluster on the upper boundary, rendered in ice
Why use Mandelbro instead of another Mandelbrot viewer?
- Arbitrary-precision deep zoom past 1050× — far beyond the 1014× ceiling of double-precision viewers
- Perturbation theory + series approximation for fast rendering even at extreme depths
- Multi-threaded Web Worker rendering uses every CPU core your device has
- Seven smooth-gradient color palettes including psychedelic, neon, fire, ice, and ocean
- Shareable URLs encode the exact view at full precision, so any deep-zoom location can be sent as a link
- Installable PWA with offline support — works on iPhone, Android, and desktop
- Touch-native with pinch-to-zoom, drag-to-pan, and double-tap zoom
- Fully open source under the MIT license — view the source on GitHub