Coin flipper
Heads or tails with cryptographic unpredictability: flip once, play best of 3/5/7 and review your session stats.
Every flip uses the least significant bit of crypto.getRandomValues: cryptographically unpredictable, unlike Math.random(). The history lives only in this tab.
Built by
Miguel Ángel Colorado Marin (MACM)
Built by
Miguel Ángel Colorado Marin (MACM)
Full-Stack Developer · Guadalajara, España
I develop web apps, digital tools and full projects — from design to deployment.
Coin flips have settled ties since forever, but a physical coin has its own trick: experienced flippers bias the outcome with height and spin. This flipper removes bias entirely: each flip draws one bit from the browser's cryptographic generator, impossible to predict or skew. Press the giant coin for a single flip, or play best of 3, 5 or 7 with the full H/T sequence — perfect for match kickoffs or board game ties. Session stats accumulate flips, heads and tails, and with enough flips you'll watch the law of large numbers converge to the promised 50% in real time.
Features
- ✓Single flip heads or tails
- ✓Best of 1, 3, 5 or 7 series with the full sequence shown
- ✓Session stats: flips, heads, tails and percentage
- ✓Real cryptographic bit: unpredictable, not Math.random()
- ✓Giant pressable coin
How do I decide between two options with a coin?
- 1
Assign the options
Decide which option is heads before flipping, never after.
- 2
Press the coin
A single flip settles simple ties instantly.
- 3
Use best of N for what matters
Best of 3/5/7 reduces the weight of a single unlucky flip.
- 4
Check your session
Heads, tails and accumulated percentage in the current tab.
Frequently asked questions
Is a virtual coin as fair as a physical one?
Fairer: a physical coin can land on its edge or be biased by a practiced hand. Each virtual flip is one bit from the cryptographic generator with exactly 50% probability and no physical trick possible.
What is the best-of-N mode for?
It damps single-flip luck: in best of 3, most outcomes (2-1, 2-0, 3-0...) require winning a majority of flips.
Is my flip history saved?
Only in the current tab's memory. It disappears on reload; nothing is sent to any server.
Related tools
Embed Coin Flipper on your site
Add Coin Flipper to any web page with a simple iframe. Free, with attribution to miguelacm.es.
<iframe
src="https://miguelacm.es/embed/coin-flipper"
width="100%"
height="700"
frameborder="0"
title="Coin Flipper — miguelacm.es"
></iframe>