Application Security
Session Token Entropy Calculator
Enter token length and encoding to compute entropy in bits and compare against OWASP's 128-bit minimum session token recommendation.
No data is transmitted — everything runs locallyTool
Example — A 32-character base62 token checked as a typical session-secret baseline.
Entropy
192.0 bits
32 chars × log2(64)
OWASP minimum
128 bits
for session IDs
Compliance
✓ Compliant
meets OWASP requirement
Crack time (est.)
>universe lifetime
brute force at 1B/sec
About this tool
Session Token Entropy Calculator
The Session Token Entropy Calculator computes entropy bits from token length and character set, comparing against OWASP minimum requirements for session IDs and CSRF tokens.
• Verify a new session token implementation meets OWASP entropy requirements
• Compare UUID v4 entropy against a cryptographically random token
• Calculate entropy for a CSRF token to confirm it's unguessable
• Explain session token entropy requirements to a development team
Affiliate disclosure
Credential and secrets management for teams. 1Password provides enterprise password management and secrets infrastructure for development teams.
View session secrets with 1Password
External site · Independent provider · We may receive a commission · Not a recommendation
FAQ
What does this tool tell you?
The Session Token Entropy Calculator computes entropy bits from token length and character set, comparing against OWASP minimum requirements for session IDs and CSRF tokens.
What affects the result most?
Session token minimum entropy: OWASP recommends 128 bits for session IDs. GUID v4: 122 bits of entropy — acceptable but UUID collision space is not unpredictable. crypto.randomBytes(32): 256 bits — ideal for session tokens and CSRF tokens.
How should I use the result?
The calculation is deterministic — the same inputs always produce the same output — so the most useful workflow is to vary one input at a time and see which factor moves the result most. That tells you where to focus your attention before committing to a decision.
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