Generate an Alphanumeric Password (No Special Characters)

Alphanumeric-Only Passwords

An alphanumeric password uses only two character classes:

• Uppercase letters (A-Z): 26 characters
• Lowercase letters (a-z): 26 characters
• Digits (0-9): 10 characters

This gives a pool of 62 characters per position, compared to 95 with full special characters included.

Entropy Impact

The reduced character set means you need a longer password to achieve equivalent security:

12 chars (alphanumeric): log2(62^12) = 71.4 bits
12 chars (all ASCII):    log2(95^12) = 78.8 bits

16 chars (alphanumeric): log2(62^16) = 95.3 bits
16 chars (all ASCII):    log2(95^16) = 105.1 bits

To compensate for the smaller pool, add 2-4 extra characters to an alphanumeric password compared to a full-charset password.

When to Use Alphanumeric Passwords

Some systems restrict or cause issues with special characters:

• WiFi passwords — some routers have trouble with certain symbols in the PSK
• Legacy systems — older software may not handle special characters in authentication
• URL-embedded credentials — special characters require percent-encoding
• Command-line usage — shell metacharacters ($, !, &, |) cause escaping issues
• CSV/TSV export — commas and quotes can break delimiter-based formats

Example Output

kR9mT2pX7nQw4bYs
Ht5vL8jB3eY6cN1x

Recommended Length

Security Level	Alphanumeric Length
Moderate	14 characters
High	18 characters
Very High	22+ characters

Mixing Case Matters

Using both uppercase and lowercase is important. A password with only lowercase alphanumeric characters draws from just 36 possibilities per position instead of 62 — nearly halving the entropy per character.