Baby Name Spelling Variants: How They Change the Rankings

Why the rankings are not what they look like

The Office for National Statistics states its rule on the cover sheet of every baby names dataset: the statistics are based on the exact spelling of the name given on the birth certificate, and grouping names with similar pronunciation would change the rankings. The ONS publishes exact names deliberately, so that users can group them if they wish. Almost nobody does, which is why the published top 10 is not a list of the ten most-used names. It is a list of the ten most-used spellings.

The effect is large. Sophia and Sofia are the same name in two dresses. Separately they sit thirteenth and seventeenth in England and Wales for 2025, with 1,547 and 1,490 babies. Together they come to 3,037, which is more than Olivia's 2,386 — so on any reading that treats them as one name, the most popular girls' name in England and Wales in 2025 was not Olivia. Every list that ranks Sophia thirteenth is reporting an artefact of transcription.

The biggest spelling splits in the 2025 data

How to read that table honestly

Not every similar name is a variant

This is where most articles go wrong. Amelia and Emilia look like spellings of one name and are not: Behind the Name derives Amelia from a Germanic element and Emily from the Roman family name Aemilius, which are separate roots that converged in sound. Isla and Ayla are not variants either; Isla is Scottish and Ayla has Turkish and Hebrew uses. Grouping those would inflate a figure rather than correct one. The table above only groups forms that trace to the same source.

Short forms are a judgement call

Theo, Teddy and Ted are diminutives of Theodore, not respellings of it, and in Britain they are now overwhelmingly registered as full legal names in their own right. Whether you group them depends on the question you are asking. If you want to know how many boys will be called Theo at school, you should group them. If you want to know how many birth certificates say Theodore, you should not. This page gives the combined figure and the components so you can choose.

Transliterated names are split hardest of all

Names written in another script have no single correct roman spelling, so they fragment further than any English name. Muhammad appears in the 2025 boys' list under at least five spellings inside the top 250, and the combined figure of 9,189 is more than twice the count for Noah in second place. The same happens to Ilyas and Elias, to Ishaq and Isaac, and to Aisha and Ayesha. A ranking built on exact spellings understates every name that arrives in English through transliteration, and it is worth saying plainly that this is a limitation of the counting method rather than anything about the names or the families who use them.

The split is getting wider, not narrower

Compare the 2025 list with the 2015 ranks the ONS prints alongside it and the pattern is consistent: names arriving from other languages and names with a fashionable alternative form both fragment further over time. Lilah, Lyla and Lila now sit at 99th, 61st and 179th respectively, three separate entries for a sound that a generation ago would mostly have been registered as Lila. Aria has acquired Arya, Ariya and Ariah. Each new spelling takes babies from the parent form and pushes it down the published ranking, which means a name can be growing in use while appearing to fall. This is the single most misleading thing about year-on-year rank changes, and it applies to every "names on the way out" article built from them.

What this means when you are choosing

Three practical consequences. First, a name can be far more common than its rank suggests: if your shortlist includes a name with a well-used alternative spelling, add the spellings together before you decide it is uncommon. Second, choosing the less usual spelling does not make a name rare — it makes the name equally common and the spelling a lifelong administrative detail your child will repeat at every appointment. Third, the spelling you register is the legal one. Changing it later means the birth registration process, not a preference.

The registries elsewhere in the UK work the same way. National Records of Scotland and the Northern Ireland Statistics and Research Agency both rank exact spellings, and NISRA notes that it pools accented and unaccented forms of the same spelling. Every comparison between countries inherits whichever convention each office uses, so cross-border rankings of a name like Sophia are not strictly comparable at all.