How SSA baby-name data works

Every number on NewbornNames traces to a single public dataset: the U.S. Social Security Administration's national "Popular Baby Names" data. This guide follows that data from the SSA's archive to the three files this site is built from, then restates the nine qualifications the SSA attaches to it — each in plain words, and each with what the committed 2025 files literally show. Every figure below is computed at build time from the same files the tables read.

The source: one file per birth year

The publisher is the SSA's Office of the Chief Actuary. It distributes the data as one archive, names.zip, at ssa.gov/oact/babynames/names.zip. Inside the archive is one plain-text file per birth year, named yobYYYY.txt — yob1880.txt through the newest year, which in the archive this site was built from is yob2025.txt. Each file holds one line per name-and-sex combination, in the form name,sex,count: the name as the SSA recorded it, the sex, and the number of Social Security card applications for U.S. births in that year carrying that name and sex.

Read into this site, the top of the 2025 list for girls is Olivia with 13,544 applications, and for boys Liam with 20,818. The archive was retrieved on July 25, 2026. It states that it reflects a 100% sample of the SSA's card-application records as of March 2026, and its latest year file is 2025, the headline year on every page here. The SSA's own description of the data, including the qualifications restated below, is its background page at ssa.gov/oact/babynames/background.html.

Public domain, attributed anyway

The dataset is a work of the United States government, which places it in the public domain under 17 U.S.C. § 105. No permission is needed to republish it and none was sought; this site attributes the SSA everywhere the data appears regardless, because attribution is how a reader checks a figure against the original.

From the archive to three committed files

A committed script, scripts/build-name-data.mjs, reads the archive locally and writes three JSON files into the site's source tree. It selects subsets and attaches ranks; it never alters a name or a count. Rank means a name's position within one sex for one year, counting down from the largest count. Because the SSA already orders its files that way and breaks ties alphabetically, the ranks on this site are the SSA's own ranks, not a re-sort. The three files, with the depth at which each one stops:

• names-latest.json — the top 1,000 boy names and top 1,000 girl names for 2025, with ranks running from #1 to #1,000 without a gap. For boys the list opens at Liam (#1, 20,818) and closes at Langston (#1,000, 227); for girls it runs from Olivia (#1, 13,544) down to Harmoni (#1,000, 252).
• names-by-letter.json — for 2025, the top 50 names per first letter per sex, each carrying its overall rank for the year. A letter with fewer than 50 qualifying names carries what exists and is never padded: in the 2025 data that is Q with 39 for boys and Q with 34 and U with 32 for girls. Across the 26 letters the file holds 1,289 boy rows and 1,266 girl rows, and because the top 50 for some initials reaches far down the year's list, its deepest overall rank is #17,092 — Urwa, on the girls' U list, with 5 applications.
• names-by-decade.json — the top 200 names per sex for 7 single-year snapshots: 1955, 1965, 1975, 1985, 1995, 2005, 2015. The earliest, 1955, opens with Michael (#1, 88,355) for boys and Mary (#1, 63,174) for girls and stops at #200, where the boys' entry is Harvey (#200, 1,289); the most recent snapshot year is 2015.

Those depths are where the committed data stops. A 2025 boy name ranked below #1,000 appears on this site only if it is among the top 50 for its initial; a name outside a snapshot's top 200 does not appear for that year at all. In both cases the honest description is "outside the committed depth", never "unused" — the second qualification below explains why.

The nine qualifications, in this guide's words

The SSA asks everyone who uses this data to acknowledge its qualifications explicitly. The methodology page lists them; here each is restated with a worked illustration from the committed files wherever the data can supply one.

1. Card applications, not birth certificates

The counts are Social Security card applications for births in the United States after 1879, not registrations of birth. The SSA notes that many people born before 1937 never applied for a card, so its early-year files undercount actual births. This site never reaches those years: every figure on it comes from one of 8 years — the 7 snapshots from 1955 to 2015, and 2025.

2. Fewer than five means absent

For privacy, the SSA omits any name given fewer than 5 times to babies of one sex in a year. Absence from a file is therefore not evidence that a name went unused — only that its count, if any, was below the threshold. The committed files show where each list sits relative to that line. In 2025, rank #1,000 for boys is Langston with 227 applications and for girls Harmoni with 252, while the smallest count anywhere in the per-letter file is 5, shared by 22 names across the 26 letters.

3. Fifty states and the District of Columbia

The national files count births in the 50 states and D.C. only. Births in U.S. territories are tabulated separately by the SSA and are not in these files, and the data says nothing about any name's use outside the United States. Every total on this site is accordingly a count of U.S. births: the 2025 top 1,000 boy names together account for 1,387,686 card applications, and the top 1,000 girl names for 1,182,238.

4. Every spelling is its own entry

The SSA counts each spelling separately, so Caitlin, Kaitlyn and Katelyn — its own example — each receive their own rank, and a "true" popularity that merged them would differ from anything in the files. This site does not compute one. What the 2025 girls' top 1,000 holds for that trio:

• Caitlin: not in the 2025 top 1,000 for girls, so outside the committed depth.
• Kaitlyn: #802, 340 applications.
• Katelyn: not in the 2025 top 1,000 for girls, so outside the committed depth.

5. Records need a year, a sex, a state and at least two characters

The SSA includes a record only when year of birth, sex and state of birth are on file and the given name is at least 2 characters long. The shortest spellings in the committed data sit close to that line. The shortest boy names in the 2025 top 1,000 are 2 letters long: Bo (#449, 698) and Ty (#813, 306). The shortest girl names run to 3 letters — 26 of them, from Mia (#6, 11,078) down to Tru (#974, 262). By this site's generator classes, where short is four letters or fewer, 183 of the top 1,000 boy names and 146 of the girl names are short.

6. Hyphens and spaces are stripped before counting

The SSA removes hyphens and spaces from its First Name field, so Julie-Anne, Julie Anne and Julieanne are counted as one entry. A check over the committed rows confirms the consequence: of the 7,355 rows in the three files, 0 contain a hyphen, a space or any character other than a letter.

7. The SSA does not edit the data

The sex recorded for a name may be wrong, and entries such as "Unknown" are left in the files. The committed data carries that literally: on the 2025 U lists, Unknown ranks #3,293 for girls with 48 applications and #2,757 for boys with 47. It is on neither top-1,000 list, but it is on both letter pages — girl names starting with U and boy names starting with U — because this site publishes what the file says rather than cleaning it.

8. Ties break alphabetically

When two names share a count in a year, the SSA ranks them in alphabetical order, so adjacent ranks can stand for identical counts. The 2025 girls' list shows this 301 times between adjacent ranks, starting at #24 Ellie and #25 Lucy, both at 6,176 applications. The boys' list shows it 287 times, starting at #132 Calvin and #133 Ryder, both at 2,710. The longest run of one count is 7 consecutive girl ranks (#862 Arisbeth through #868 Soraya, all at 313) and 8 consecutive boy ranks (#883 Emory through #890 Trey, all at 269).

9. Rankings are per sex

A name used for both boys and girls has a separate rank and count in each list. The SSA's own example is Micah, which in 2025 is #90 for boys with 3,817 applications and #909 for girls with 291. In all, 82 names appear on both 2025 top-1,000 lists. The one that sits highest on both is Parker, #102 for boys (3,477) and #106 for girls (2,536). The widest split is August, #81 for boys against #962 for girls. Across the 26 per-letter lists, 123 names appear on both sexes' lists.

Reading the site with these in mind

With the qualifications in hand, the tables read plainly. A rank is a position in one sex's list for one year; a count is a number of card applications; a missing name is below the SSA's threshold or outside the committed depth. The top 100 boy names and top 100 girl names pages carry the 2025 lists to #100 with counts; each of the 52 letter pages carries its initial to #50 with overall ranks; the generator's decade eras are the 7 snapshots named above. For the arithmetic of ranks, counts and the spread between them, see Reading ranks and counts; for the full pipeline and the tests that enforce it, the methodology page.

Frequently asked questions

Source: every name, rank, and count on this page comes from the U.S. Social Security Administration's national baby-names dataset (1955–2025 data, from Social Security card applications). It is public-domain U.S. government data; names given fewer than 5 times in a year are excluded by the SSA, spelling variants are counted separately, and the data covers U.S. births only. Full caveats on the methodology page.