FairToss: Fair Coin Flip

Real coins aren't perfectly fair. FairToss is. In a 2023 study, František Bartoš and colleagues at the University of Amsterdam recorded 350,757 real coin flips. The result, published in the Journal of the American Statistical Association (2025): a flipped coin lands on the same side it started on about 50.8% of the time. The starting side and the hand that tosses it leave a small but measurable bias. FairToss removes both. Each result is picked by your phone's cryptographically secure random number generator - the same class of generator used to create encryption keys - before the animation even starts. There is no starting side and no hand, so every flip is an even 50/50 choice. Don't take our word for it: open the Fairness screen and run 1,000,000 test flips right on your device. FairToss counts the results and runs a chi-square test so you can check the balance yourself. THREE WAYS TO DECIDE • Yes / No - for quick answers to everyday questions • Heads / Tails - the classic coin toss • Custom - put your own two options on the coin: "Pizza / Sushi", "Me / You", "Go / Stay" A FLIP THAT FEELS REAL • Smooth 3D coin toss with sound and haptic feedback • Shake your phone to flip, or just tap • History of your recent flips RESPECTS YOU • No ads • No data collection - no accounts, no analytics, no tracking • Works fully offline Settle an argument with a friend, choose who goes first, pick dinner or break a tie. FairToss gives you a quick, honest answer - and the numbers to back it up.

First release of FairToss! • Flip a realistic 3D coin: Yes / No, Heads / Tails or your own two words • Every result comes from your phone's cryptographically secure random generator • Fairness screen: run 1,000,000 test flips with a chi-square check • Tap, press Flip or shake your phone • History of your recent flips • No ads, no data collection, works offline