The choice between either is and either are depends on the grammatical job of either. Use a singular verb when either is a pronoun or determines one singular option. In an either A or B subject, make the verb agree with the subject closest to it.
Subject-Verb Agreement with Either
Either takes a singular verb when it means “either one” or introduces one singular count noun. Purdue OWL includes either among the singular indefinite pronouns that require singular agreement[1].
Use either is when either stands alone as a pronoun:
- “Either is acceptable.”
- “Either is available after lunch.”
- “Either of the routes is suitable.”
- “Either of these explanations is possible.”
The phrase of the routes does not turn the pronoun either into a plural subject. The grammatical head remains either, meaning “either one.” The plural noun inside the of phrase identifies the available choices.
Use a singular verb when either determines a singular noun:
- “Either option is acceptable.”
- “Either answer is grammatically possible.”
- “Either route is shorter than the motorway.”
- “Either candidate is qualified.”
In each sentence, the subject noun—option, answer, route, or candidate—is singular. The form either are would therefore be incorrect.
A useful diagnostic is to replace the subject with either one. If the replacement preserves the meaning, singular agreement is normally required:
- “Either of the keys is missing.” → “Either one is missing.”
- “Either proposal is workable.” → “Either one is workable.”
How Does Agreement Work with Either … Or?
**When either … or joins two subjects, the verb normally agrees with the nearer subject.** Washington State University’s usage guide illustrates this proximity rule and distinguishes it from singular pronominal either[2].
When both subjects are singular, use a singular verb:
- “Either the editor or the writer is responsible.”
- “Either Maya or Daniel has the key.”
- “Either the bus or the train is available.”
When both subjects are plural, use a plural verb:
- “Either the editors or the writers are responsible.”
- “Either the buses or the trains are delayed.”
- “Either the teachers or the students have the key.”
When the subjects differ in number, the nearer one controls the verb:
- “Either the teacher or the students are presenting.”
- “Either the students or the teacher is presenting.”
- “Either the manager or the employees are responsible.”
- “Either the employees or the manager is responsible.”
These pairs change only the order of the coordinated subjects. The verb changes because the nearest subject changes, not because one subject receives greater emphasis.
The phrase “second noun” can be a shortcut when the entire subject appears before the verb, but nearest subject is the clearer rule. It describes the grammatical relationship instead of relying on an item’s numerical position in a sentence.
Correct and Incorrect Either Is and Either Are Examples
The following comparisons show the source of agreement in each pattern.
| Sentence | Verdict | Why |
|---|---|---|
| “Either is suitable.” | Correct | Pronominal either means “either one.” |
| “Either are suitable.” | Incorrect | Pronominal either is singular. |
| “Either answer is suitable.” | Correct | Answer is a singular subject noun. |
| “Either answers are suitable.” | Incorrect for the intended meaning | Use “Either answer is suitable” to select one of two answers. |
| “Either the cat or the dog is outside.” | Correct | Both coordinated subjects are singular. |
| “Either the cats or the dogs are outside.” | Correct | Both coordinated subjects are plural. |
| “Either the cat or the dogs are outside.” | Correct | The nearer subject dogs is plural. |
| “Either the dogs or the cat is outside.” | Correct | The nearer subject cat is singular. |
Do not decide agreement merely by locating the first plural word. In “Either of the answers is acceptable,” answers is plural, but it sits inside an of phrase. The subject is the singular pronoun either.
Do not treat every occurrence of either as the subject. In “Either ketchup or mustard is available,” either … or marks a coordination of two singular nouns. This sentence illustrates the correlative construction, not standalone pronominal either.
How Can You Rewrite Awkward Mixed-Number Sentences?
Reorder or recast a mixed-number sentence when proximity agreement sounds distracting. The original proximity rule remains valid, but a rewrite can make the relationship easier to read.
One option is to put the plural subject nearer the verb:
- More awkward: “Either the employees or the manager is responsible.”
- Often smoother: “Either the manager or the employees are responsible.”
Another option is to give both alternatives the same grammatical number:
- “Either the manager or an employee is responsible.”
- “Either the managers or the employees are responsible.”
A third option is to move the alternatives out of the subject position:
- “Responsibility lies with either the manager or the employees.”
- “The responsible party is either the manager or one of the employees.”
These rewrites solve a style problem without inventing a different agreement rule. Deleting either alone does not change how an or-joined subject agrees with its verb.
What Is the Quick Decision Process?
Use these four steps:
- Identify whether either stands alone, determines one noun, or belongs to either … or.
- Use a singular verb for pronominal either: “Either is correct.”
- When either determines a noun, agree with that noun: “Either option is correct.”
- In an either … or subject, agree with the nearer coordinated subject: “Either the option or the alternatives are correct.”
The shortest reliable answer is therefore: either is for “either one” and singular nouns; either are only when a plural subject controls the verb, most commonly as the nearer subject in an either … or construction.