btcrecover is an open source Bitcoin wallet password and seed recovery tool. It is designed for the case where you already know most of your password or seed, but need assistance in trying different possible combinations.
If you mostly know your recovery seed/mnemonic (12-24 recovery words), but think there may be a mistake in it, please see the Seed Recovery Quick Start.
If you find btcrecover helpful, please consider a small donation:3Au8ZodNHPei7MQiSVAWb7NB2yqsb48GW4
Free and Open Source - anyone can download, inspect, use, and redistribute this software
Supported on Windows, Linux, and OS X
Support for Unicode passwords and seeds
Multithreaded searches, with user-selectable thread count
Experimental GPU acceleration for Bitcoin Unlimited/Classic/XT/Core, Armory, and derived altcoin wallets
Wildcard expansion for passwords
Typo simulation for passwords and seeds
Progress bar and ETA display (at the command line)
Optional autosave - interrupt and continue password recoveries without losing progress
Automated seed recovery with a simple graphical user interface
“Offline” mode for nearly all supported wallets - use one of the extract scripts (click for more information) to extract just enough information to attempt password recovery, without giving btcrecover or whoever runs it access to any of the addresses or private keys in your Bitcoin wallet.
“Nearly offline” mode for Armory - use an extract script (click for more information) to extract a single private key for attempting password recovery. btcrecover and whoever runs it will only have access to this one address/private key from your Bitcoin wallet (read the link above for an important caveat).