Pick a Winner – Provably Fair, Verifiable Draws
Draw a random winner you can prove was fair. Publish a commitment before you draw, reveal the seed after, and let anyone re-verify the result. Free, no sign-up, and everything runs in your browser — nothing is stored or uploaded.
Publish this commitment before closing entries:
Winners
Revealed seed
Fair on the entries provided. For full transparency, publish your entry list when you post the commitment.
Paste a draw's seed, commitment and entries — or load a certificate file — to independently confirm the winner.
Anyone can run a giveaway. The hard part is convincing the people who entered that the draw was honest. When you announce a winner, some participants inevitably wonder whether you re-spun the wheel until a friend won, or picked the result before ever pressing the button. A regular random picker gives you a name; it cannot give you proof. This tool was built to solve exactly that problem: it lets you pick a winner and hand every participant a way to check the result themselves, without having to trust you at all.
The approach is borrowed from a method called provably fair, long used where trust between an operator and a crowd is thin. Instead of asking people to believe the draw was random, the tool produces evidence that can be independently verified. Below is exactly how it works, who it helps, and how to use it well.
How the Verifiable Draw Works
The tool follows three steps: commit, reveal, and verify. Each one runs entirely in your browser using the standard Web Crypto API, so no data ever leaves your device.
🔒 1. Commit (before the draw)
The tool generates a secret random seed and shows you its SHA-256 fingerprint, called the commitment. You publish this fingerprint before entries close. It reveals nothing about the seed, but it locks it in — you can no longer change it later.
🎯 2. Reveal (the draw)
Once entries are final, the tool selects the winner using a fixed formula based on the seed and the entry list, then reveals the seed. Because the result is fully determined by those two inputs, it can be reproduced by anyone.
✅ 3. Verify (by anyone)
Any participant checks that the SHA-256 of the revealed seed matches the fingerprint you published earlier, then re-runs the same formula on the same entries. If they land on the same winner, the draw is proven fair.
Why publishing the commitment first matters. The fingerprint is announced before the entry list is known. That timing is the whole point: you cannot have chosen a seed that favours a specific person, because when you locked the seed you did not yet know who would enter. Reveal the seed afterward and the math either matches your published fingerprint or it does not — there is nowhere to hide.
The Formula, in Plain Terms
The winner is chosen deterministically, which simply means the same inputs always produce the same output. The tool computes a keyed hash (HMAC-SHA256) from two things: the secret seed and your exact list of entries. That hash is converted into a position in the list, and the entry at that position wins. For multiple winners, the process repeats without picking the same entry twice.
- Same seed + same entries = same winner, every time. This is what makes independent verification possible.
- Change one character of the seed or the list, and the winner changes completely. Tampering is immediately visible.
- The method is versioned so a draw run today can still be verified in the future.
Who Uses This, and Why
📣 Social media giveaways
Creators running Instagram, YouTube, or TikTok giveaways can post the commitment in a story or pinned comment before closing entries, then share the certificate when they announce the winner.
🎟️ Raffles and prize draws
Clubs, communities, and small businesses that draw prizes can give members a way to confirm the outcome instead of taking the organizer's word for it.
🔬 Research and sampling
Anyone selecting participants or samples at random can attach a reproducible seed to their methodology, so the selection can be re-run and audited later.
🏫 Classrooms and teams
Teachers and team leads who pick names for rewards, presentation order, or duties can show the choice was impartial when someone questions it.
How to Run a Fair Draw, Step by Step
- Before you start, generate the commitment and publish the fingerprint publicly — in the giveaway post, a pinned comment, or a story. Timestamp it if you can.
- Also publish your entry list, or its source, when you post the commitment. This closes the one gap the seed cannot: it shows you did not add or remove entries afterward.
- When entries close, paste the final list, choose how many winners to draw, and reveal the seed.
- Share the certificate. Download the HTML or JSON certificate and post it alongside the result so anyone can verify.
- Point people to the Verify tab. Participants load your certificate or paste the seed, commitment, and entries to confirm the winner for themselves.
What This Tool Does — and What It Does Not Claim
Honesty about limits is part of what makes a fairness claim credible, so here it is plainly. The draw is provably fair on the list of entries you provide. The cryptography guarantees that, once you commit, you cannot change the seed and cannot influence which entry the formula selects. What the tool cannot police is what you put in the list — an organizer could still add or omit an entry. That is why publishing your entry list with the commitment matters: it makes the input transparent, not just the process. Used together, the commitment and the published list leave no room for a rigged result.
Frequently Asked Questions
How do I prove my giveaway was fair?
Publish the commitment fingerprint before you close entries, keep the entry list public, and after the draw share the revealed seed and the certificate. Anyone can then confirm the fingerprint matches the seed and that the seed and entries produce the announced winner.
What is a commitment, exactly?
It is a SHA-256 hash of the secret seed — a short string that acts as a sealed envelope. It proves you fixed the seed at a certain moment without revealing what it is. When you later reveal the seed, anyone can hash it and check it matches the commitment you published.
Can I re-run the draw until I get a result I like?
Not without it being obvious. The winner is fully determined by the seed and the entries. If you change the seed, its hash no longer matches the commitment you published, so anyone verifying the draw will see the mismatch immediately.
Do I need any technical knowledge to verify a draw?
No. Open the Verify tab, load the certificate file or paste the seed, commitment, and entries, and the tool does the checks for you, showing whether the draw is confirmed or fails.
Is my data private?
Yes. Every step runs locally in your browser using the built-in Web Crypto API. Your entries, seed, and results are never uploaded or stored anywhere.
Can I draw more than one winner?
Yes. Set the number of winners before drawing. The tool selects them one after another from the same seed without repeating an entry, and every winner remains independently verifiable.