How many shuffles is enough

January 2026

For a 52-card deck the usual answer is seven riffle shuffles: fewer and traces of the original order survive, more and you are mostly wasting time. It is a satisfying result because the cut-off is sharp — the deck goes from noticeably ordered to thoroughly mixed within a shuffle or two.

What that means for a list of names

Nothing, happily. Software does not riffle: it walks the list once, swapping each item with a randomly chosen position at or after it. One pass is already a uniform shuffle, and doing it twice buys you exactly nothing extra.

The classic mistake is swapping each item with a position chosen from the whole list instead of the remaining tail. It looks harmless, produces plausible-looking output, and quietly favours some orders over others.