Teaching tool

Mining game

Find a nonce that makes the hash start with enough zeros. Toy SHA-256 search — not a real miner.

How to play

  1. A block needs a special hash (it must start with enough zeros).
  2. Type any nonce (a number) and click Mine.
  3. If the hash does not qualify, try another nonce — that search is the “work.”

In Bitcoin, miners change the nonce until SHA-256(block header) meets the network target. You're doing a tiny version of that search. No real coins.

Nonce

Nonce = the number you change each try.

Enter a nonce (try 0) and press Mine to see a hash.

Target (leading zeros)

Target = the hash must start with N zeros.

Must start with 000
Attempts 0
Typical work ~4096 tries

Need 3 leading zeros (hash starts with 000).

1 zero 2 zeros 3 zeros

About ~16 / ~256 / ~4096 tries on average for 1 / 2 / 3 zeros.

Hash (SHA-256)

Hash = a fingerprint of the block header + nonce.

Enter a nonce (try 0) and press Mine to see a hash.

Nothing hashed yet. Enter a nonce (try 0) and press Mine. You will see a 64-character fingerprint here.

Previous hash —
This hash —
Header hashed —

Block header

Block header = the data being hashed this round (previous hash + time + nonce).

Previous hash and time stay fixed this round. Only the nonce changes.

Time 16 Sep 2026 13:09 UTC
Previous block hash 0000000000000000000163bbb5f4f7761b2bb12a0f777540f7c3d07dec1c1171