🎉 Shared birthday (23 people) vs 👯 Having identical twins
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You're 125.0× more likely to share a birthday in a group of 23
than to have identical twins
Periods differ: Shared birthday (23 people) is framed as group of 23 people, while Having identical twins is per birth (natural, approx.). The multiplier is a raw ratio of the 1-in-X figures — not a normalized lifetime risk. Compare cautiously.
Shared birthday (23 people)
~50.7% (about 1 in 2)
group of 23 people
Having identical twins
1 in 250
per birth (natural, approx.)
How we calculated this
Each figure is “1 in X.” The larger X is the rarer event. Dividing that number by the more common one gives the multiplier: you're 125.0× more likely to share a birthday in a group of 23. When the periods differ, this is a raw ratio of those figures, not a lifetime-normalized risk.
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You're 125.0× more likely to share a birthday in a group of 23 (~50.7% (about 1 in 2), group of 23 people) than to have identical twins (1 in 250, per birth (natural, approx.)). ⚠️ Periods differ (group of 23 people vs per birth (natural, approx.)) — compare cautiously. — How Likely Is That? https://www.howlikelyisthat.com/compare/birthday-paradox-odds-vs-odds-of-having-identical-twins
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