By vs Per

When to use each in English, with meaning, register, and examples.

By

High-frequency chunk A1 preposition

Per

Top 1,000 (very common) A2 preposition

	By	Per
Pronunciation	🇬🇧 /["/baɪ/"]/ 🇺🇸 /["/baɪ/"]/ Hear By	🇬🇧 /["/pə(r)//pɜː(r)/"]/ 🇺🇸 /["/pər//pɜːr/"]/ Hear Per
Meaning	near or beside something	for each or by means of.
Example	The book was written by a famous author.	Rooms cost £50 per person, per night.
Register	Neutral	Neutral
How common	High-frequency chunk	Top 1,000 (very common)
CEFR level	A1	A2
Part of speech	preposition	preposition
Collocations	by the way, by chance, by bus	per person, per day, per month, per the agreement
Antonyms	away from, against	excluding, less than
Common mistakes	Confused with 'beside' — 'by' indicates proximity, 'beside' indicates being directly next to., Using 'by' to mean 'with' in contexts like 'by giving' instead of 'by using' or 'by means of'.	'Per' is sometimes confused with 'by', especially in informal contexts., 'Per' is often improperly used with plural nouns (e.g., 'per items' instead of 'per item')., Learners may forget to follow 'per' with a clear noun or amount.
Usage notes	Used to indicate location, proximity, or the means of doing something. Often used in expressions of time, such as 'by Monday'. Avoid in formal writing when a more specific term can be used.	Use 'per' when giving rates or amounts, like 'per hour' or referencing a rule, like 'as per your request'. It’s formal and often appears in written English.

Frequently asked questions: By vs Per

What's the difference between By and Per?

By: near or beside something Per: for each or by means of.

Are By and Per the same CEFR level?

By: A1, Per: A2 on the CEFR scale.

Can I use By and Per interchangeably?

Not always. By and Per are related and overlap in some contexts, but they differ in register, how common they are, and usage, so swapping one for another can change the meaning or tone. Check the differences above before substituting.