Is an Online Random Picker Really Random?
Understand browser entropy, bias, practical fairness and the limits of general-purpose online drawing tools.
Number Tools
Coin Flip
Flip one or many virtual coins and see heads/tails totals and percentages.
🔒 Your list is processed locally in your browser. It is not uploaded unless you create a share link.
Input & settings
Result
Configure the tool, then run it.
Result history
- No results yet.
Quick answer
What does this tool do?
Coin Flip generates independent Heads or Tails results with equal probability and reports totals, percentages and the full sequence. Batch mode supports up to 1,000 flips for demonstrations and simple simulations.
- Outcomes
- Heads or Tails
- Probability
- 50% per flip
- Batch size
- 1 to 1,000
- Random source
- Web Crypto
Why use this tool?
Simulate independent fair coin flips for classroom probability examples, turn order and harmless tie-breaking. Run one flip for a quick answer or a larger batch to compare the observed totals with a 50/50 expectation.
How to use it
- Choose how many flips to perform.
- Turn sound or motion on or off.
- Flip the coin.
- Review totals, percentages and the complete sequence.
Common use cases
- Teach probability
- Choose a starting player
- Resolve a simple tie
Practical examples
- Choose the starting player in a friendly game.
- Compare observed results across 100 classroom flips.
- Resolve a harmless two-way tie.
How it works
Random values come from window.crypto.getRandomValues(). Lists are shuffled with an unbiased Fisher–Yates process. For a wheel, the result is chosen before the animation; for weighted entries, each positive weight defines its share of the total probability.
Limits to understand
- Small samples often differ from exactly 50/50.
- Past flips do not change the next flip’s probability.
- Not intended for wagering or certified draws.
Privacy
Input and results stay inside this browser during normal use. Local saving is optional. If you select Create Share Link, the visible list and settings are uploaded under a hard-to-guess token and expire automatically.
Last reviewed: August 27, 2026
Coin Flip FAQ
Is my list uploaded?
No. Entries are processed in your browser unless you explicitly create a share link.
What kind of randomness is used?
The browser Web Crypto API supplies unbiased random values. Wheel animation only reveals a result chosen in advance.
Does it work on phones?
Yes. The controls, results and wheel adapt to current mobile browsers and keyboard navigation.
Can I reuse my settings?
Yes. Device storage can remember recent settings unless you turn off local list saving.
Is this suitable for a certified lottery?
No. It is a general-purpose classroom, work, event and decision tool, not a regulated drawing system.
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Prepare a clean entry list, state rules in advance and preserve a useful result record.