How rare are twins?
About 1 in 33 babies born in the U.S. in 2024 was a twin: 109,195 of 3,628,934 births, a rate of 30.1 per 1,000, according to the CDC’s final birth data for 2024. Worldwide the share is lower: about 1 in 42 children born in 2010–2015 was a twin, Monden, Pison and Smits found across 165 countries.
Two babies share each delivery, so the odds that a delivery is twins are about half the per-baby rate: roughly 1 in 65 in 2024.
What are the odds of having twins?
It depends most on the mother’s age. In 2024 about 1 in 123 deliveries to mothers younger than 20 were twins, rising to about 1 in 68 at 25–29 and 1 in 55 at 40 and older. Pick an age in the tool above to see the 2024 odds beside 2014.
The age gap has narrowed sharply. In 2014, 66.0 of every 1,000 babies born to mothers 40 and older were twins, about 1 in 29 deliveries. By 2024 that was 35.6, a 46% fall, the CDC’s June 2026 report shows, with smaller falls of 27% at 35–39 and 18% at 30–34. Rates for mothers under 25 barely changed.
Twins by the mother’s race and Hispanic origin
In 2024, Black mothers had the highest twin birth rate, 42.0 per 1,000 births, about 1 in 24 babies. White mothers followed at 31.3. The rate was lowest for Asian (23.3) and Hispanic (23.4) mothers, about 1 in 43 babies. From 2014 to 2024 the rate fell 15% for White mothers and 3% for Hispanic mothers, and rose 5% for Black mothers.
How rare are identical twins?
Identical twins come from one fertilized egg that splits. They occur in about 4 of every 1,000 deliveries, roughly 1 in 250, and the rate is similar everywhere in the world. Fraternal twins, from two eggs, make up the rest and account for most of the differences between countries and over time. U.S. birth certificates record how many babies were born together, not whether twins are identical, so there is no official U.S. count.
Triplets, quadruplets and more
In 2024 the U.S. recorded 2,444 triplets (1 in 1,485 babies), 130 quadruplets (1 in 27,915) and 14 quintuplets or more (1 in 259,210). As deliveries, that is roughly 1 in 4,400 for triplets, 1 in 110,000 for quadruplets and about 1 in 1.3 million for quintuplets or more.
Triplets and larger sets have become much rarer. Their rate, 71.3 per 100,000 births in 2024, is down 63% from the 1998 peak of 193.5, and the number born has fallen 66% since the 2003 high of 7,663.
Are twins becoming less common?
Yes. The U.S. twin birth rate climbed 76% from 18.9 per 1,000 births in 1980 to 33.2 in 2009 and peaked at 33.9 in 2014. It then fell 11% to 30.1 in 2024, the lowest rate since 2002. The number of twins born fell 19% over the same decade, from 135,336 to 109,195, while single births fell 9%.
Worldwide the trend runs the other way. The global twinning rate rose by a third, from 9.1 to 12.0 twin deliveries per 1,000 deliveries between 1980–1985 and 2010–2015, to about 1.6 million sets of twins a year. The study’s authors attribute much of that rise to medically assisted reproduction and to women having children later.
Twins around the world
Africa has the highest twinning rate, 17.1 twin deliveries per 1,000, followed closely by North America (16.9). Oceania (14.8) and Europe (14.4) come next. South America (9.3) and Asia (9.2) have the lowest. Africa and Asia together are home to about 80% of the world’s twin deliveries, since most of the world’s births happen there. These regional figures count deliveries, not babies, so they are not directly comparable with the U.S. rates per 1,000 births.
Twins are usually born early
About 6 in 10 twins (61.5%) born in 2024 arrived preterm, before 37 weeks, against 8.8% of single babies. Nearly all triplets (98.4%) and quadruplets (98.5%) were born preterm. More than half of twins (55.6%) weighed under 2,500 grams (5 pounds 8 ounces) at birth.
Where the numbers come from
U.S. counts and rates are from the CDC’s Births: Final Data for 2024 (Tables 12 and E) and the twin rates by the mother’s age from NCHS Health E-Stat 117, both June 2026. They count live births; “twins” are babies born in twin deliveries. Odds per delivery are our approximation: each set counted once, from babies divided by set size. World and regional rates and the identical-twin rate are from Monden, Pison and Smits in Human Reproduction (2021). Download every figure as a CSV from the chart above.
Good questions
What are the odds of having twins?
About 1 in 65 deliveries in the U.S. in 2024 were twins, from 109,195 twins among 3,628,934 births. The odds rise with the mother’s age, from about 1 in 123 for mothers younger than 20 to about 1 in 55 for mothers 40 and older.
How rare are twins?
About 3% of babies: 30.1 of every 1,000 born in the U.S. in 2024, or 1 in 33. Worldwide, about 1 in 42 children born in 2010–2015 was a twin.
How rare are identical twins?
About 4 in every 1,000 deliveries, or 1 in 250, a rate that is similar everywhere in the world. Most of the variation in twinning between countries and over time is in fraternal twins. U.S. birth certificates do not record whether twins are identical.
How rare are triplets?
2,444 triplets were born in the U.S. in 2024: 1 in 1,485 babies, or roughly 1 in 4,400 deliveries.
How rare are quadruplets?
130 quadruplets were born in the U.S. in 2024: 1 in 27,915 babies, or roughly 1 in 110,000 deliveries. Only 14 babies were quintuplets or more.
Are twins becoming less common?
Yes, in the U.S. The twin birth rate fell 11% from its 2014 high of 33.9 per 1,000 births to 30.1 in 2024, the lowest since 2002. It had risen 76% from 1980 to 2009.