Skip to main content
Dictionary
Store
Blog
World
Help
Advertise
Chat
System Status
Information Collection Notice
Trademark Concerns
reCAPTCHA Privacy
Terms of Service
reCAPTCHA Terms
Privacy Policy
Accessibility
Report a Bug
Data Request
Contact Us
Security
DMCA
© 1999–2026 Urban Dictionary ®
Mugs
Tees
Hoodies
Pro Customization
Create unique products with your own words and definitions
Preview
Personalize Your Design
Your Word
Your Definition
In probability theory, Birthday paradox is the phenomenon concerning the probability that, in a set of n randomly chosen people, at least two will share the same birthday. The birthday paradox is the counterintuitive fact that only 23 people are needed for that probability to exceed 50%. The birthday paradox is a veridical paradox, i.e. a paradox that produces counter-intuitive results, but is demonstrated to be true nonetheless.
Text fits
Save
Cancel