Note these addreses are derived from the BIP32 Extended Key
Do NOT use phrases from books, lyrics from songs, your birthday or street address, keyboard mashing, or anything you think is random, because chances are overwhelming it isn't random enough for the needs of this tool.
Using Diceware Passphrase as one personal phrase is a good idea with minimum 6 words. Also one string with 40 random characters is a good password.
As phrase like "I'm smart" will generate 24 BIP39 words. As much as 24 words is strong phrase, your "I'm smart" is not, because now another smart person can use this tool to try to generate 24 BIP39 words from dump short personal phrases.
Read more at the official BIP39 spec
Read more at the official BIP44 spec
You can use this tool without having to be online.
In your browser, select file save-as, and save this page as a file.
Double-click that file to open it in a browser on any offline computer.
Alternatively, download it from https://github.com/skironDotNet/bip39
Get the source code at - https://github.com/skironDotNet/bip39
Originally based on - https://github.com/Coinomi/bip39
Originally based on - https://github.com/iancoleman/bip39
BitcoinJS - https://github.com/bitcoinjs/bitcoinjs-lib
jsBIP39 - https://github.com/iancoleman/jsbip39
jQuery - https://jquery.com/
Twitter Bootstrap - http://getbootstrap.com/