Coin Flip
Flip a virtual coin for quick, fair decisions. If you also need intelligent helper for crossword and word puzzle solving, explore WordWhiz for a complementary toolkit.
Leave empty for default (Heads/Tails). Try "Yes/No", "Pizza/Burger", etc.
50% HEADS / 50% TAILS
Adjust to create a biased coin. 50/50 is fair, other values favor one side.
Show confetti animation when you get 3 or more of the same result in a row
📊 Probability Calculator
Probability of HEADS:
50%
1 in 2
Probability of consecutive results:
2 in a row
25.00%
1 in 4
3 in a row
12.50%
1 in 8
4 in a row
6.25%
1 in 16
5 in a row
3.13%
1 in 32
7 in a row
0.78%
1 in 128
10 in a row
0.10%
1 in 1,024
How are these probabilities calculated?
• Single flip: 50% chance for HEADS, 50% for TAILS
• Consecutive flips: Multiply the probability by itself. For example, getting HEADS 3 times in a row is 50% × 50% × 50% = 12.50%
🔐 How It Works: True Randomness
RollPick uses cryptographically secure randomness to ensure every flip is truly fair and unpredictable.
What is crypto.getRandomValues()?
crypto.getRandomValues() is a web standard for generating cryptographically secure random numbers. Unlike Math.random(), which is predictable and not suitable for security, crypto randomness uses the operating system's entropy sources.
Entropy sources include: mouse movements, keyboard timings, hardware noise, CPU temperature variations, and other unpredictable system events.
Why is this better than Math.random()?
Math.random() uses a pseudo-random number generator (PRNG) that produces a predictable sequence of numbers based on a seed value. Given the same seed, it will always produce the same sequence.
crypto.getRandomValues() uses a cryptographically secure PRNG (CSPRNG) that is:
- Unpredictable: Cannot be guessed or predicted, even with knowledge of previous values
- Non-repeating: Extremely long period before any pattern emerges
- Secure: Suitable for cryptography, gambling, and security-critical applications
Can you prove the results are random?
Yes! With enough flips, the results should approach the expected probability. Try flipping 1000 times with a fair coin (50/50) - you'll get close to 50% heads and 50% tails.
Statistical tests like chi-squared tests can verify randomness. The crypto API passes all standard randomness tests used by cryptographers and security experts.
Note: In small samples, you might see "streaks" (like 5 heads in a row) - this is normal! True randomness includes clusters and patterns. It's the human brain that expects perfect distribution.
🛡️ Trust & Transparency: All randomization happens in your browser. No server-side manipulation. Open-source and auditable. Your results are as random as physically possible on a computer.