Solitaire Lab

Does a rule change make solitaire easier? Don’t guess — test it on real deals.

📊 Run an experiment →

How the lab works

  • 🔮 Predict first. Pick which rule you think wins more deals — before you look.
  • 👯 A fair test. Every deal is played BOTH ways, so the only difference is the rule.
  • 🔍 A solver that never lies. Each deal is proven won, proven lost, or marked not sure yet when the search runs out of time.
  • 📏 How sure are we? You get an “at least … at most …” range and a 95% interval — more deals make it narrower.

Most experiments use “thoughtful” Klondike: the solver can see every card (the way researchers study it), drawing one card at a time. The free-cell experiment uses FreeCell, where every card is face-up for real — so a “lost” there means no player could ever win that deal. Download your results as a table for a chart.

Everything runs on your device — no accounts, nothing sent anywhere.