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About this tool
Flip 20 coins at once and see the longest run of the same side.
The Coin Toss Streak Game flips 20 fair coins in one go and reports the longest run of the same face, along with the full H/T sequence in two blocks of ten and the heads-versus-tails count. It exists to make one point visible: streaks are ordinary. Press regenerate as many times as you like and watch how often a run of four, five or six shows up in a sequence that is genuinely 50/50.
Open Coin Toss Streak Game on AltFTool — it loads instantly in your browser.
Open the tool and 20 flips are dealt straight away, then press Generate to deal a fresh set whenever you like
Read the Result line, which prints the run as H and T characters in two blocks of ten, with Longest streak shown underneath it
Compare the Heads and Tails tiles for the split across the 20 flips, then press Generate again to watch the longest streak shift from round to round
It scans the whole 20-flip sequence and hands back the longest same-side run, so you do not have to count it yourself.
The full H/T string is printed in two rows of ten, so you can see exactly where the run happened.
Regenerate re-runs all 20 flips at once, which is what makes the distribution of streak lengths obvious after a dozen tries.
Four or five, most of the time. Across fair 20-flip runs the longest streak averages about 4.7, with 4 being the single most common answer and roughly 46 percent of runs reaching 5 or more.
No. Every flip here is an independent 50/50 draw, and a run of six or longer still turns up in about one in four sets of 20 flips. Streaks are what random data looks like; their absence would be the suspicious result.
Twenty per round, displayed as two groups of ten. It also counts heads and tails separately, which will often land at something like 12-8 rather than a tidy 10-10.
Yes, each flip is an even 50/50 split with no weighting and no memory of earlier flips. An uneven heads-to-tails count in a single 20-flip round is normal variance, not bias.