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Free Bitcoin tools

Small, private tools for the things BIPs define. They run in your browser and never ask for your seed phrase or keys.

  • BIP 39 word list: The full BIP 39 word list: all 2048 seed words with their numbers, 0-based index and 11-bit binary, in English and the nine other official languages.
  • Derivation path builder: Build or decode any Bitcoin derivation path like m/84'/0'/0'/0/0: each level explained, plus the address type, xpub/ypub/zpub prefix and descriptor.
  • Bitcoin address checker: Check any Bitcoin address offline: validate its checksum and see its type (P2PKH, P2SH, P2WPKH, P2WSH, P2TR), network, script and the BIPs behind it.
  • Transaction size calculator: Work out a Bitcoin transaction's weight, size in vbytes and fee for any mix of legacy, SegWit, Taproot and multisig inputs and outputs, byte by byte.
  • Bitcoin unit converter: Convert between BTC, mBTC, bits, satoshis and millisatoshis exactly, with no rounding errors. 1 BTC is 100,000,000 sats. No prices, runs in your browser.
  • Bitcoin payment link and QR code: Create a bitcoin: payment link and QR code with amount, label and message, or decode one field by field. Follows BIP 21 and BIP 321 and runs offline.
  • Bitcoin Script opcodes: Every Bitcoin Script opcode with its hex and decimal value, what it does, which are disabled or reserved, tapscript changes and the BIPs behind them.