Formula & Calculator
Recovery Phrase Entropy from Word Count
Approximates the security strength of common BIP-39 recovery phrase lengths, showing how much stronger longer phrases are.
Interpretation
Security Level ≈ Word Count × 10.3 bits (BIP‑39 approx.). Approximate security from BIP‑39 recovery phrase word count.
Variables
| Symbol | Quantity | Unit |
|---|---|---|
| Security Level | Approximate security strength | bits |
| Word Count | Number of words in the recovery phrase |
What it means
Each word in a BIP‑39 seed phrase adds about 10.3 bits of entropy (log₂(2048)). This is used to estimate the security level. Understanding this helps users evaluate the security of their recovery phrase.
Worked example
Recovery Phrase Entropy – Two Detailed Examples
Real‑World| Parameter | Value |
|---|---|
| Word Count | 12 |
| Parameter | Value |
|---|---|
| Word Count | 24 |
Common mistakes
- Recovery phrase entropy (approx): Word count × 10.3 bits per word (BIP‑39).
- 10.3 bits: Derived from log₂(2048) ≈ 11 bits, but BIP‑39 has checksum bits.
- Approximation: 12 words ≈ 128 bits, 24 words ≈ 256 bits.
- Security level: Should be sufficient for cryptographic security.
Applications
Recovery phrase entropy from word count approximates the security level of a seed phrase based on the number of words, using the BIP‑39 standard (about 10.3 bits per word). This is a quick way to estimate the security of different seed lengths. Users can use it to compare 12‑word and 24‑word phrases. Understanding this entropy helps in choosing a sufficiently secure recovery phrase.
- Evaluating the security of seed phrases
- Choosing between 12‑word and 24‑word seeds
- Security education for crypto wallets
- Understanding the importance of word count
- Educational understanding of seed phrase security
Frequently Asked Questions
Security Level ≈ Word Count × 10.3 bits (BIP-39 approx.). For a 12-word phrase, this gives ~124 bits (actual entropy is 128 bits after checksum). For 24 words, it's about 247 bits (actual 256 bits). This is a quick way to compare phrase lengths.
While 24 words offer more security, 12 words (128 bits) is already far beyond any realistic brute-force threat. The main difference is future-proofing against quantum computers. For most users, 12 words are sufficient.
BIP-39 uses a wordlist of 2048 words (2^11). Each word encodes 11 bits of entropy. So word count × 11 gives the total bits, minus checksum bits. The actual entropy is slightly less.
The checksum is derived from the entropy and ensures the phrase is valid. For a 12-word phrase (128-bit entropy), the checksum is 4 bits, leaving 128 bits of entropy. For 24 words (256-bit entropy), checksum is 8 bits, leaving 256 bits.
24 words are often used for higher security needs or for users who want maximum future-proofing. 12 words are more convenient and widely supported. The choice is usually offered during wallet setup.
No, you cannot modify a seed phrase. You would need to generate a new one with the desired word count and transfer your funds.
It is longer to write down and store, increasing the chance of errors. It also takes longer to enter on a hardware wallet. For most users, the extra security is unnecessary.
Yes, the order is critical. The phrase is a sequence; changing the order creates a different private key. Always write the words in the exact order.