when
/wɛn/
Binary Representation
11-bit index: 11111010001 (decimal 2001)
Position
#2002 of 2048
Hex Index
0x7D1
4-Letter Prefix
when
About "when" in BIP39
"when" is the #2002 word
in the official BIP39 English mnemonic wordlist. It is encoded as the 11-bit binary value
11111010001
(decimal index 2001), placing it at the 98% mark of the full 2048-word list.
The 4-letter prefix "when" uniquely identifies this word among all 2048 entries. At just 4 characters, "when" is one of the shorter words in the BIP39 list, making it quicker to type during wallet recovery but potentially easier to confuse with similar short entries.
Near the end of the wordlist (index 2001), "when" is part of the "W" letter group with 69 entries total, positioned at #33 in that group. Words in the upper range of the list have binary representations with more leading 1s.
In a 12-word seed phrase, each word encodes 11 bits of entropy. The probability of "when" appearing in any specific position of a randomly generated phrase is 1 in 2048 (≈ 0.049%). A complete 24-word phrase encodes 256 bits of entropy, providing security equivalent to a key space of approximately 1.16 × 10⁷⁷ — far beyond the reach of brute-force attacks.
Word #2002 in the Other 9 BIP39 Wordlists
Every official BIP39 wordlist has exactly 2048 entries, so index 2001 encodes the same 11-bit value
(11111010001) in every language.
A wallet configured for one of these languages would use this word instead of "when":
Similar Words — Check Carefully During Recovery
2 BIP39 words differ from "when" by just a single letter — the most common source of typos when a seed phrase is entered by hand: