offline · single file · no dependencies · view source to audit
1 — collect entropy
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target
d8 rolls. each roll = 3 bits. 43 rolls → 128 bits, 86 rolls → 256 bits.i
one flip = one bit. heads = 1, tails = 0.
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paste an existing BIP-39 mnemonic (12, 15, 18, 21, or 24 words). checksum is verified locally.
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enter 12-24 words
0 bits collected0%
2 — pipeline · entropy → mnemonic
Araw bitsi—
start adding entropy above
↓ group bits into bytes · to hex
Bentropy · hexi4 bits per nibble · 8 bits per byte
appears once ≥4 bits collected
↓ SHA-256(entropy) · take leading CS bits as checksum
Csha-256(entropy) → checksumiCS = ENT / 32 bits
computed once entropy is complete
↓ concat entropy + checksum · split into 11-bit groups
D11-bit groups → wordlist indicesi2^11 = 2048 words
first group appears at 11 bits
↓ lookup · index i → wordlist[i]
Emnemoniciincomplete
↓ Derive to Verify
Ffingerprint & first address (offline · derive to verify)i
before funding — verify restoration
Derive the master fingerprint and first receive address below, then compare against what your hardware wallet shows on-screen. Match = mnemonic + path + script type reproduce the same keys. Mismatch = wrong wordlist, typo, unsupported path, or silent bug.
Trust model: this tool runs entirely in-browser with no network calls (view source to audit). Still, treat one tool as a check on the other — ideally run this on an air-gapped machine, or cross-verify with a second independent tool like Ian Coleman's BIP-39 tool. Never enter a live mnemonic on a networked machine.