The Birthday Paradox Explained
This animation shows why just 23 people give roughly a 50% chance that two share a birthday. It visualizes the surprising jump by counting pairs of people rather than people themselves, showing how comparisons grow much faster than group size. Bars and a running probability curve build up person by person, revealing the tipping point near 23. Useful for students and teachers exploring probability, combinatorics, and why intuition about chance often misleads us.
Narrated · 9:16 · Preview before teaching · automatic layout checks do not establish subject accuracy
The prompt that made it
Explain why 23 people are enough for a roughly 50% chance of sharing a birthday. Audience knows basic maths but isn't technical. Make it surprising and visually intuitive.
Make the next one in this series
- Show how the same pair-counting idea explains password and hash collisions
- Animate how the probability curve changes if birthdays aren't evenly distributed
- Visualize the general formula for the birthday problem with any number of days
