A or An Checker
Free tool · no sign-up · runs in your browser
Type a word, an acronym or a number and find out whether it takes a or an, and why.
Try:
Article
a university
Rule: It starts with a “y” sound (like “you”), a consonant sound, so use “a” even though the first letter is a vowel.
The checker follows the usual rules and a short list of exceptions. For a rare word, confirm in a dictionary.
a or an: examples
It starts with a vowel sound, so use “an”.
- apple → an apple
- egg → an egg
- island → an island
- orange → an orange
- umbrella → an umbrella
- engineer → an engineer
- idea → an idea
- old → an old
- only → an only
- ugly → an ugly
It starts with a consonant sound, so use “a”.
- book → a book
- cat → a cat
- house → a house
- tree → a tree
- woman → a woman
- horse → a horse
- year → a year
- hero → a hero
- person → a person
- xylophone → a xylophone
The h is silent, so the word starts with a vowel sound: use “an”.
- hour → an hour
- honest → an honest
- heir → an heir
- honour → an honour
- hourly → an hourly
It starts with a “y” sound (like “you”), a consonant sound, so use “a” even though the first letter is a vowel.
- university → a university
- unicorn → a unicorn
- uniform → a uniform
- user → a user
- European → a European
- unit → a unit
- usual → a usual
- euro → a euro
- utensil → a utensil
- ukulele → a ukulele
“One” starts with a “w” sound, a consonant sound: use “a”.
- one → a one
- once → a once
Initials and letters are read by the name of the first letter (…).
- FBI → an FBI
- MBA → an MBA
- CEO → a CEO
- TV → a TV
- HR → an HR
- X-ray → an X-ray
- T-shirt → a T-shirt
- U-turn → a U-turn
- MP3 → an MP3
- e-mail → an e-mail
A number is read aloud first (…), then the sound decides.
- 8 → an 8
- 11 → an 11
- 18 → an 18
- 80 → an 80
- 1 → a 1
- 10 → a 10
- 100 → a 100
- 7 → a 7
- 800 → an 800
- 1,000 → a 1,000
This acronym is said as a word, so the first sound decides, like any other word.
- NASA → a NASA
- NATO → a NATO
- UNESCO → a UNESCO
- IKEA → an IKEA
- ASAP → an ASAP
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Use “a” or “an” by sound, not by letter
The rule for a and an is about sound. Use “an” before a vowel sound and “a” before a consonant sound. Most of the time the first letter tells you: an apple, a book. The confusion comes from words where the spelling and the sound disagree, and this checker is built for exactly those.
Silent h, “yoo” sounds and “one”
A silent h is not pronounced, so the word starts with a vowel sound: an hour, an honest person, an heir. Words such as university, unicorn, uniform, user and European begin with a “y” sound, which is a consonant sound, so they take a: a university, a European country. “One” begins with a “w” sound: a one-way ticket. Compare an umbrella and an uncle, where the u really is a vowel sound.
Acronyms, letters and numbers
Say an initialism letter by letter and use the name of its first letter: an FBI agent (“eff”), an MBA (“em”), but a CEO (“see”). Acronyms said as words follow the usual rule: a NASA project, a NATO member.
Numbers are read aloud first: an 8 (“eight”), an 11 (“eleven”), an 80, but a 1 (“one”) and a 10 (“ten”). Letters work the same way: an X-ray, an S-bend, a T-shirt, a U-turn.
Hotel, historic and herb
The old rule “an hotel” and “an historic” is out of date: modern English uses a hotel and a historic event. “Herb” differs by region. Americans say “an herb”, with a silent h, and the British say “a herb”. The tool shows both articles for these words. To check plurals and verb endings as well, use the spelling rules checker.
Frequently asked questions
Is it a or an before h?
It depends on the sound. If the h is pronounced, use a: a house, a horse, a hotel. If it is silent, use an: an hour, an honest man, an heir.
Is it a university or an university?
A university. The word begins with a “yoo” sound, which is a consonant sound, even though u is a vowel letter. The same goes for a unit, a user and a European.
Is it a or an before an acronym?
Say the name of the first letter and use that sound: an FBI agent, an MBA, a CEO, a UFO. If the acronym is pronounced as a word, treat it as a word: a NASA mission.
Is the word I type sent anywhere?
No. The checker runs in your browser and nothing is sent or stored.