What is an alphanumeric password?
An alphanumeric password uses the 62 characters A–Z, a–z and 0–9, and nothing else. Without symbols, each character carries about 5.95 bits of entropy instead of 6.55 — so you simply make the password a little longer to reach the same strength. A 20-character alphanumeric password (119 bits) is stronger than an 18-character password with symbols (118 bits).
When to choose letters and numbers only
- Systems that reject symbols. Older banking portals, routers, set-top boxes, some enterprise single sign-on screens.
- Configuration files and shells. Characters like
$,",',,#and&have special meaning in Bash, YAML,.envfiles, SQL and connection strings. An alphanumeric secret never needs escaping. - URLs and API tokens. Alphanumeric strings are URL-safe without percent-encoding.
- Typing on TVs and consoles. On-screen keyboards hide symbols behind extra menus; letters and digits are much faster to enter. Tick Easy to read as well.
Recommended lengths
| Length | Entropy | Good for |
|---|---|---|
| 12 | 71 bits | Low-value accounts with MFA |
| 16 | 95 bits | Everyday accounts |
| 20 | 119 bits | Email, banking, admin accounts |
| 32 | 190 bits | API keys, service accounts, database passwords |
Uppercase only or lowercase only?
You can untick upper- or lowercase to create case-insensitive codes (for example, voucher or recovery codes that people read aloud). With 36 characters (A–Z, 0–9), each character gives 5.17 bits, so 24 characters provide roughly 124 bits. Turn on Easy to read to drop ambiguous characters like 0/O and 1/I.
Last updated: · Reviewed by the Password Generator team