Technology & Computing
UUID v4 Collision Probability Calculator
Estimate the probability of a birthday-paradox collision among randomly generated UUID v4 values.
Your inputs
Change any value to update the result instantly.
Collision probability
0%
Random bits used
122
UUIDs generated
1,00,00,00,000
UUIDs needed for 50% chance
27,14,92,26,69,39,54,45,000
UUID v4 has 122 random bits (6 bits are fixed for version/variant), giving a space of about 5.3×10^36 values.
Formula and working
P(collision) ≈ 1 − e^(−n²÷(2×2^122)), where UUID v4 has 122 random bits
- 1
Collect the inputs
Number of UUIDs generated = 1,000,000,000
- 2
Apply the formula
P(collision) ≈ 1 − e^(−n²÷(2×2^122)), where UUID v4 has 122 random bits
- 3
Result
Collision probability = 0
Frequently asked questions
Important limitation
This is an educational estimate based only on the values and formula shown. Verify current rates, rules, units, and professional standards before relying on the result. It is not personalized financial or investment advice.
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