🇺🇸
Liter
American English
Standard spelling in the USA.
🇬🇧
Litre
British English
Standard in UK, Canada, Australia.
The difference between liter and litre is purely geographical. There is no difference in meaning or pronunciation. Both words refer to the same unit of volume in the metric system. If you are writing for an audience in the United States, use the spelling ending in -er. For virtually every other English-speaking country, including the United Kingdom, Canada, and Australia, the correct spelling ends in -re.
Quick Tip: To remember the difference, think of the US ending. Liter ends in ER, just like the word America.
Where to Use Each Spelling
Language rules often come down to location. While the definition remains constant—equal to 1,000 cubic centimeters—the spelling changes based on the dictionary you follow.
Liter (US)
This is the standard spelling in American English. It is widely used in science, engineering, and daily life within the United States.
Examples:
- “We bought a two-liter bottle of soda.”
- “The engine has a 3.5-liter capacity.”
Litre (UK/Intl)
This is the preferred spelling in British English and is the standard generally accepted by the International Bureau of Weights and Measures (BIPM).
Examples:
- “The car holds 50 litres of petrol.”
- “Add half a litre of milk to the mixture.”
The “-er” vs. “-re” Pattern
This spelling variation is not unique to volume measurements. It follows a systematic pattern established largely by Noah Webster, the American lexicographer who wanted to simplify English spelling. He believed words should be spelled the way they sound.
You can see this same shift in many other common words. If you know the rule for one, you know the rule for all.
Milliliters, Deciliters, and Centiliters
The spelling rule you choose applies to all variations of the word. You should never mix spellings within the same document. If you choose the American style, all your measurements must follow suit.
🇺🇸 American Style:
Milliliter, Centiliter, Deciliter, Kiloliter
🇬🇧 British Style:
Millilitre, Centilitre, Decilitre, Kilolitre
A Note on Science and Metrication
In the scientific community, consistency is vital. The SI (Système International) generally uses the spelling litre. However, major American scientific organizations, such as NIST (National Institute of Standards and Technology), officially use liter.
If you are writing an academic paper, check the specific style guide of the journal or institution you are submitting to. They usually specify which dictionary (Oxford or Merriam-Webster) to follow.
Consistency is Key
The only “wrong” way to use these words is to switch between them in a single text.
✅ Do This
“The center of the town has a theater and a shop that sells liters of water.” (All US)
❌ Avoid This
“The centre of the town has a theater and a shop that sells litres of water.” (Mixed)
