Coin Flip
Randomly determines heads or tails.
Input Information
Click the coin to flip
Result
Heads
0
0%
Total Flips
0
flips
Tails
0
0%
Make fair decisions with virtual coin flipping!
Coin flipping is the simplest yet fairest decision-making tool, with each result having a 50% probability. Designed so heads and tails appear with equal probability through computer algorithms.
Recording multiple flip results and analyzing statistics helps intuitively understand basic probability and statistics concepts, making it useful for educational purposes.
A versatile decision-making tool for game order, simple decisions, probability learning, educational simulations, and more.
- 1
Click flip
Press flip to toss the coin with animation — it lands on heads or tails.
- 2
Check result
Heads/tails is shown; cumulative stats (counts and total flips) update.
- 3
Repeat
Repeat as many times as you like to experience statistical patterns.
Example — Simulating 10 flips
10 flips: 6 heads, 4 tails (60%). This seems biased, but with only 10 trials, such variance is normal. Increase to 100 or 1000 flips to watch the ratio converge toward 50%.
Coin flipping is the most basic example of a discrete probability distribution.
Coin Flip Usage Tips
QAre heads and tails always 50:50?
Theoretically yes. Physical coins have slight weight asymmetries; a Harvard study of 350,757 flips found heads at 50.67%, but this is within random variance. This tool uses Math.random() for perfectly uniform probability.
QCan I get 60 heads out of 100 flips?
Yes. The probability of ≥60 heads in 100 flips is ~2.8% (binomial). This illustrates the Law of Large Numbers: small samples show large variance, but thousands of flips converge to 50%.
QWhat's the probability of the same side streak?
Probability of n consecutive same sides = (1/2)^n. Five in a row ≈ 3.1%; ten ≈ 0.1%. A common misconception — 'tails is due after three heads' — ignores that each flip is independent.
QHow good is Math.random()'s randomness?
Math.random() uses Mersenne Twister, adequate for general purposes but not cryptographically secure. For fairness-critical applications, crypto.getRandomValues() is more appropriate. For entertainment, Math.random() suffices.
QCan I flip multiple coins at once?
This tool flips one coin at once. For simultaneous multi-coin simulation, run it consecutively — e.g., for 3 coins, flip three times to build a 'heads-tails-heads' pattern.