Cailyn
Feminine
Cailyn is overwhelmingly a girls’ name — 5,549 girls against 5 boys since 1880.
Cailyn belongs to the very large family of American names built on a Cai- or Kay- opening and a -lyn ending, and it stands close to Caitlin, which is Irish for Katherine.
How old is the name Cailyn?
Cailyn first appears in US birth records in 1979 — 46 years ago. The typical Cailyn alive today was born around 2008, making them about 17 years old. About 5,500 people named Cailyn are estimated to be alive in the US today.
When was the name Cailyn most popular?
Cailyn peaked in 2009, reaching #724 nationally. Today it ranks #3712, 2,988 places below that high. See the whole 2009 chart.
Where it comes from
Origin, sound and short forms
Our story of Cailyn
Ours, offered as ours. The Cai- opening reached American naming largely through Caitlin, which arrived from Ireland in the twentieth century and was immediately respelled — Katelyn, Kaitlin, Caitlyn, Cailyn. Somewhere in that process the connection to Katherine, four languages back, became invisible. Cailyn is at the far end of it: a name whose ancestry is genuinely long and entirely undetectable from the letters.
Meaningnot established
Not established
No source is established. Caitlin is documented as the Irish form of the Norman French Cateline, itself from Katherine, whose own origin is unknown. The Cai- and -lyn pieces of modern American naming are the other likely source, and neither is confirmed.
Pronouncing Cailyn
KAY-lin
Two syllables, first stressed. Cailyn, Kaylin and Kaylyn are said identically.
Nicknames for Cailyn
Moderate
What the data says
146 years of official birth records
The long climb, and where it stands now
The same years in position rather than babies
- First recorded
- 1979
- Most girls named
- 2009401 — the highest on record
- Peak rank
- #724reached in 2009
- Change vs 2024
- −16.7%40 in 2025, from 48
Rank is a position, a count is a headcount, and they move independently — a name can hold its rank while the number of babies behind it falls. Source: U.S. Social Security Administration.
Cailyn in other languages
The same name elsewhere
- Caitlín in Irish — related form
- Kaylin in English — spelling variant
Strongest US states over the last decade: Texas, Florida, Georgia.
Cailyns among us
people named Cailyn are estimated to be alive in the US today
About 1 girl in 40,182 born in 2025 was named Cailyn
Estimated from SSA birth records and published actuarial life tables. Method
Spellings of Cailyn
- #3712
- Cailyn on the 2025 chart
- #447
- counting every spelling
The SSA counts spellings, not names. Cailyn went to 40 girls in 2025, but Kaylynn, Kaylin and Kailyn and the rest below are the same name said out loud. Together the 12 spellings went to 616, which makes it the 447th most-given girls’ name of the year — 3,265 places above the chart.
and 4 rarer spellings.
About 1 girl in 2,609 born in 2025 was given one of these spellings — against 1 in 40,182 for Cailyn itself.
Spellings are grouped by a fixed rule that folds interchangeable English spellings of one sound (ck/k, ph/f, x/ks, a non-initial y for i) and keeps vowels apart, so Sean and Shawn stay separate names. It errs towards splitting: a family here is never larger than the truth. SSA national data, 2025. Method
Is it right for you
What happens to a name after it peaks
The Waneta test
Every popular name lives one long story — a climb, a peak, a slow settling back. Cailyn's later chapters haven't been written yet, so we borrowed them: Waneta climbed just as high around 1923, and its whole arc is on record. Line the two peaks up, and Waneta's path sketches the road Cailyn is walking now.
Cailyn sits in the calm middle of the cycle — neither chasing a wave nor sliding off one. Middle-of-the-cycle names age slowly and predictably.
A scored estimate from 146 years of naming cycles — not a prophecy. Great names outlive statistics. How this is scored
Where Cailyn is headed
Cailyn is easing off slowly — about 15% fewer babies a year by 2030 if the trend continues.
Medium confidence — fitted on official counts through 2025.
A damped-trend projection of the official birth data — a sketch of momentum, not a promise. Every name's forecast, ranked.
Cailyn beside its neighbors
The names ranked closest to Cailyn in 2025, in babies rather than position — the bars are to scale.
US girls given each name in 2025.
The trade-off
- Read correctly on sight by every English speaker.
- Lyn and Callie are both usable short forms with their own lives.
- Six letters and two syllables, quick to write.
- There are at least six live spellings of this sound and she will recite hers for life.
- Caitlin is a genuine Irish name that this one resembles without descending from.
- There is no documented meaning for this spelling.
Nobody names a baby alone.
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What they receive
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Cailyn
Feminine · #3712 in the U.S.
Frequently asked
- How many Cailyns are there in the world?
- No country counts the world's names, so there is no worldwide figure — anyone quoting one is estimating. About 5,500 people named Cailyn are estimated to be alive in the US today.
- How do you spell Cailyn?
- Cailyn is one of 8 recorded spellings. Kaylynn is the more common one — 134 births in 2025 against 40 for Cailyn.
- How popular is the name Cailyn in 2025?
- Cailyn ranks #3712 among US girl names in 2025, with 40 babies given the name.
- How rare is the name Cailyn?
- About 1 in every 40,182 US girls born in 2025 was named Cailyn — 40 in all.
- Will my child share the name Cailyn with classmates?
- Cailyn will almost certainly be the only one in school.
Ranked beside Cailyn
Names sitting at a similar level of popularity right now.
Monet#3712 · Barrett#3712 · October#3712 · Aubrianna#3712 · Mishka#3712 · Berkleigh#3712 · Zailey#3712 · Ora#3712
Looking for what else is popular rather than what resembles Cailyn? See the current top 100.
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US figures from the Social Security Administration. 1880–2025. Data & methodology
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