Shuffle Simulator
Play around to see how well your deck is actually being shuffled.
Deck
Cards in deck
Colours
Card types
1
Rising sequences (fully random ≈ 25.5)49
Neighbours still together (fully random ≈ 1)0.0
Average distance moved (fully random ≈ 16.7)History
Each row represents the deck with each shuffle. The Runs column counts rising sequences: sequences of cards still in their original relative order.
Where does each card end up?
Runs the selected shuffle 3,000 times from a sorted deck and plots how often each card lands in each position. A perfect shuffle would spread every column evenly; bright dots and streaks are bias.
Shuffles per trial
3
Riffle Shuffle
Hover or tap the map to read a cell.
Axes
Every trial starts from the sorted deck: the fresh, unshuffled gradient with card 1 (deepest red) on top and card 50 (violet) on the bottom. The x-axis is that starting order: each column is one card, numbered by where it sits in the sorted deck. The y-axis is where a card ends up after shuffling: position 1 at the bottom of the final deck, position 50 at the top, matching the deck strip above.
Reading the map
A cell glows at full strength when a card lands there four times more often than chance (2.0%). Under a truly random shuffle every cell sits at 2.0%, giving an even, faint wash of colour.
Riffle
One riffle leaves a bright diagonal band: cards barely move. Rising sequences roughly double with each riffle, which is why seven riffles is the classic answer for a 52-card deck. The perfect riffle is fully deterministic, so the map shows single dots, and 21 of them in a row put a 50-card deck back in perfect order.
Pile
Picked up in a fixed order, a pile shuffle is the same permutation every time, so the map is a scatter of solid dots and repeating it just cycles. It separates clumps, which is why players use it, but on its own it adds no randomness. Random pickup order helps only a little.
Hindu
Packets move as blocks, so the top and bottom trade places while local neighbours survive. Look for the anti-diagonal and the slow fade of the history rows: it takes many more of these than riffles to mix.