This simple tool, checks all possible checksum words for a provided english bip39 23-words sequence. For each sequence, 8 possible words are valid and they will be displayed. The test is made by bruteforce check against all the possible bip39 words of english dictionary.
Since the sequence is inside a file on disk, be careful to run the script on a totally offline air-gapped system.
pip3 install mnemonic
fill a file with the 23 words sequence (single line, words separed by a space) you want to test. Then just run the script. You will get a list of valid 24 words bip39 sequence as checked valid.
usage: bip39checksum.py [-h] -s SEQUENCE
optional arguments:
-h, --help show this help message and exit
-s SEQUENCE, --sequence SEQUENCE
Specify sequence words file to check. Single line, words separed by a space