Flip 100 coins at once and see the heads count, the streaks and the chance of each
Processed in your browser. Nothing is uploaded. Updated on 25 Oct 2026.The classroom probability experiment without the sore thumb: 100 coin flips in one press, laid out in order with a count of heads and tails and the longest run of one side. Change the count to 10 or 1,000 to compare.
The number of flips is already set to 100.
Press Flip 100 coins.
Read the Heads and Tails totals and the percentage bar.
Press Copy for the full sequence, or download it as .txt.
Most people expect a fair coin to alternate more than it does, so the page also works out how likely the longest streak really is in 100 flips.
Coin Flip tosses a fair virtual coin. Press Flip for one toss, or choose 10, 100, 1,000 or any number up to 10,000 to flip them all at once. The result appears on the coin and in words, and every batch is added to a running score for the session.
Each flip comes from crypto.getRandomValues, the random source your browser uses for encryption keys. The tool takes one random byte per flip and reads its last bit: of the 256 possible bytes, 128 end in 0 and 128 end in 1, so heads and tails are exactly equal. There is no pattern to learn and no seed to guess.
For more than one flip you get the full sequence in order, the heads and tails count with percentages, the longest run of one side and the run the sequence ended on. People tend to expect a fair coin to switch sides more often than it does, so the page also works out, exactly rather than by simulation, the chance of seeing a streak at least that long in the same number of flips. In 100 flips, a run of seven is more likely than not.
The rest of the article, and all 6 questions about Coin Flip, are on the Coin Flip page.
Each flip here uses one byte from crypto.getRandomValues, the browser's secure random source, and reads its last bit. Exactly 128 of the 256 possible bytes are even and 128 are odd, so heads and tails each have a 50% chance with no rounding. Earlier flips have no effect on the next one.
Choose 100 from the count buttons, or type any number up to 10,000, and press Flip. All the results appear in order, with the heads and tails count, the percentage of each, the longest streak and the chance of a streak that long happening by luck.
Usually not. Long runs are common in fair flips: in 100 flips the chance of at least one run of seven or more of the same side is about 54%. The page calculates that chance exactly for your number of flips, so you can judge a streak instead of guessing.
Yes. Let one person call heads or tails, then press Flip. The coin spins and lands, and the result is shown in large text so everyone can see it. A running score keeps count for a best of three, and Reset clears it.
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Same job, other tools: Random Number 1 to 100 – A random whole number from 1 to 100, or a list of them, in one click.
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