Either vs Whether

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

Either

Top 2,000 (common) A2

Whether

Top 1,000 (very common) B1 conjunction

Most common: Whether

	Either	Whether
Pronunciation	🇬🇧 /["/ˈaɪðə(r)//ˈiːðə(r)/"]/ 🇺🇸 /["/ˈiːðər//ˈaɪðər/"]/	🇬🇧 /["/ˈweðə(r)/"]/ 🇺🇸 /["/ˈweðər/"]/
Meaning	one or the other of two options	If something is true or not.
Example	You can park on either side of the street.	He seemed undecided **whether** to go **or** stay.
Register	Neutral	Neutral
How common	Top 2,000 (common)	Top 1,000 (very common)
CEFR level	A2	B1
Part of speech		conjunction
Collocations	either option, either way, either choice	whether or not, decide whether, whether to choose
Antonyms	neither, none	if not, unless
Common mistakes	'Either' confused with 'neither'., Using 'either' with more than two items., Mistaking 'either' as a plural form.	Confusing 'whether' with 'if' in certain contexts., Using 'whether' without a second alternative., Omitting 'if' when it should be used instead of 'whether'.
Usage notes	Use 'either' when presenting two choices. It's more formal in written contexts. Avoid using 'either' with more than two options as it becomes incorrect.	Use 'whether' to introduce options or alternatives, especially when discussing choices. It's appropriate in both spoken and written English, but can be formal in certain contexts. Avoid using it when only one option exists.

See it in real clips

Better Call Saul › S1 E1

Now, you either pay the $3...

Eleven of us didn't think of it either.

Breaking Bad › S1 E6

And we can't talk to Emilio either, because...

Better Call Saul › S1 E1

Now, you either pay the $3...

Eleven of us didn't think of it either.

Either

Sherlock › S1 E1

Just so I know whether I could have beaten you.

the question of whether we're a hung jury or not.

Peaky Blinders › S1 E1

whether or not you're lying.

Sherlock › S1 E1

Just so I know whether I could have beaten you.

the question of whether we're a hung jury or not.

Whether

Frequently asked questions: Either vs Whether

What's the difference between Either and Whether?

Either: one or the other of two options Whether: If something is true or not.

Which is more common: Either and Whether?

Whether is the most common in everyday English.

Which is more advanced: Either and Whether?

Whether is the highest level, at B1, on the CEFR scale.

Are Either and Whether the same CEFR level?

Either: A2, Whether: B1 on the CEFR scale.

Can you show an example of each?

Either: You can park on either side of the street. Whether: He seemed undecided **whether** to go **or** stay.

Can I use Either and Whether interchangeably?

Not always. Either and Whether 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.