When to use 'a' vs 'an'?

Use 'a' before consonant sounds, 'an' before vowel sounds (not just letters).

Use 'the' for specific, known, or previously mentioned nouns.

Article Usage Helper — When to Use A, An, The

Use ___ (three underscores) where article is missing, or let the tool detect.

Click "Suggest articles" to see analysis.

Definite vs Indefinite
‘the’ = specific; ‘a/an’ = non-specific, first mention.

First vs subsequent mention
First: ‘a/an’. Later: ‘the’.

Countable vs uncountable
Countable singular needs article; uncountable can be zero article.

Geographic names
Rivers, seas, plural countries → ‘the’. Single mountains, lakes → zero.

Proper nouns
Most proper nouns → zero article. Exceptions: the UK, the USA.

General statements
Plural/uncountable → zero article: “Dogs are loyal.”