Bitcoin Hash Tool

Double SHA-256

Block headers · Transaction IDs · Address checksums · Merkle roots

1
Enter hex input (spaces & newlines ignored)
Output byte order:
2
First SHA-256
SHA-256 (round 1)
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3
Second SHA-256 (Double SHA-256)
Double SHA-256 (natural byte order)
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Two common use cases:
Block hash / TxID: bytes are reversed after double-hashing (Bitcoin's little-endian display convention). Use the "Reversed" mode.
Address checksum: take the first 4 bytes of the double-hash in natural order — no reversal. Use the "Natural" mode.

Genesis block header → reversed double SHA-256 = 000000000019d6689c085ae165831e934ff763ae46a2a6c172b3f1b60a8ce26f