Flip a Coin
Assign options to each side for quick decisions, or just flip for fun.
Tap to flip
Press Space to flip
Coin Flip Probability
Fair 50/50
Each flip is independent with exactly P = 0.5 probability for either side. Past results never influence future flips.
Streaks Are Normal
In 100 flips, a streak of 6+ identical results is expected about 80% of the time. Streaks feel surprising but are statistically ordinary.
The Formula
Probability of N same results in a row: (1/2)^N. So 10 heads in a row = 1/1024, or about 0.1%.
Law of Large Numbers
Over thousands of flips, the heads/tails ratio converges toward 50/50. Try the 100x multi-flip to see it in action.
This tool FAQ
Is the coin flip truly random?
Yes. This coin flipper uses the Web Crypto API (crypto.getRandomValues) to generate cryptographically secure random numbers. Each flip has an exact 50/50 probability of landing heads or tails, independent of all previous results.
Why do I sometimes get long streaks of heads or tails?
Streaks are a normal part of randomness. In 100 fair coin flips, there is roughly an 80% chance of seeing a streak of 6 or more identical results in a row. The human brain tends to expect more alternation than true randomness produces -- this is called the gambler's fallacy.
How does the multi-flip mode work?
Multi-flip mode instantly simulates flipping 2, 5, 10, or 100 coins at once. Each individual flip uses the same cryptographic random number generator. The results are added to your running statistics and history, letting you quickly observe the law of large numbers.
Can I use this coin flip for making real decisions?
Absolutely. A fair coin flip is one of the simplest and most unbiased ways to make a binary decision. You can assign custom labels to heads and tails using the decision inputs. The result is generated locally in your browser with no server involvement.
What is the probability formula for consecutive coin flips?
The probability of getting the same result N times in a row is (1/2)^N. For example, 5 heads in a row has probability 1/32 (about 3.1%), and 10 heads in a row has probability 1/1024 (about 0.1%). Each flip is independent, so past results do not change future odds.
Does this tool save my flip history?
Flip history and statistics are kept in your browser session only. Nothing is sent to a server. When you refresh the page or click Reset All, all data is cleared. No account or installation is required.
Privacy & Limitations
- All calculations run entirely in your browser -- nothing is sent to any server.
- Results are estimates and may vary based on actual conditions.
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This tool FAQ
Is the coin flip truly random?
Yes. This coin flipper uses the Web Crypto API (crypto.getRandomValues) to generate cryptographically secure random numbers. Each flip has an exact 50/50 probability of landing heads or tails, independent of all previous results.
Why do I sometimes get long streaks of heads or tails?
Streaks are a normal part of randomness. In 100 fair coin flips, there is roughly an 80% chance of seeing a streak of 6 or more identical results in a row. The human brain tends to expect more alternation than true randomness produces -- this is called the gambler's fallacy.
How does the multi-flip mode work?
Multi-flip mode instantly simulates flipping 2, 5, 10, or 100 coins at once. Each individual flip uses the same cryptographic random number generator. The results are added to your running statistics and history, letting you quickly observe the law of large numbers.
Can I use this coin flip for making real decisions?
Absolutely. A fair coin flip is one of the simplest and most unbiased ways to make a binary decision. You can assign custom labels to heads and tails using the decision inputs. The result is generated locally in your browser with no server involvement.
What is the probability formula for consecutive coin flips?
The probability of getting the same result N times in a row is (1/2)^N. For example, 5 heads in a row has probability 1/32 (about 3.1%), and 10 heads in a row has probability 1/1024 (about 0.1%). Each flip is independent, so past results do not change future odds.
Does this tool save my flip history?
Flip history and statistics are kept in your browser session only. Nothing is sent to a server. When you refresh the page or click Reset All, all data is cleared. No account or installation is required.