Plural of Idea: Is It Ideas, Idea's, or Ideas'?
Quick answer
The plural of idea is ideas: just add s, with no apostrophe. Use ideas for more than one idea, idea's for the singular possessive (one idea's owner), and ideas' for the plural possessive (several ideas' owner).
The plural of idea is ideas. Idea is a regular noun, so you form the plural the simplest way: add s. There is no apostrophe in the plural. One idea, two ideas.
The confusion is almost never about the plural itself. It is about the apostrophe. Ideas, idea's, and ideas' all sound the same but mean different things: a plural, a singular possessive, and a plural possessive. This page lays out all three clearly, with correct examples, so you never have to guess.
Definition
noun
1.A thought, plan, or mental picture formed in the mind. Plural: ideas.
One idea grew into a dozen ideas by the end of the week.
Ideas: the plural (no apostrophe)
Use ideas whenever you mean more than one idea. This is the plural, and it never takes an apostrophe. Adding an apostrophe here (idea's) is one of the most common punctuation mistakes in English, sometimes called the greengrocer's apostrophe.
- Correct: She had three ideas for the logo.
- Correct: Good ideas are easy to start and hard to finish.
- Wrong: She had three idea's for the logo.
- Wrong: Good idea's are easy to start.
Idea's: the singular possessive (one idea)
Use idea's when one single idea owns or is linked to something. The apostrophe plus s shows possession for a singular noun. This is the only time a lone idea takes an apostrophe.
- Correct: The idea's appeal was obvious from the first pitch.
- Correct: That idea's biggest weakness is the cost.
- Note: idea's can also be a contraction of idea is or idea has, as in this idea's going to work.
Ideas': the plural possessive (many ideas)
Use ideas' when more than one idea owns or is linked to something. Because the plural already ends in s, you add only an apostrophe after the s. No extra s is needed.
- Correct: All the ideas' strengths were listed on one page.
- Correct: The ideas' impact was felt across the whole team.
- Wrong: All the ideas's strengths were listed.
Quick comparison
Read these three side by side and the pattern is clear. Plural means more than one and takes no apostrophe. Singular possessive puts the apostrophe before the s. Plural possessive puts the apostrophe after the s.
- ideas: more than one idea (two good ideas).
- idea's: belonging to one idea (the idea's cost).
- ideas': belonging to more than one idea (the ideas' costs).
How to decide in one step
Ask whether something belongs to the idea. If nothing is owned and you just mean more than one, use ideas with no apostrophe. If something belongs to a single idea, use idea's. If something belongs to several ideas, use ideas'. When in doubt, most sentences just want the plain plural, ideas.
Ideas vs ideals: a related mix-up
One more word gets confused with the plural of idea: ideals. Ideas are thoughts and plans; ideals are values and standards you aspire to. They are different words, not different spellings of the same one, so the plural of idea is always ideas, never ideals.
Frequently asked questions
What is the plural of idea?
The plural of idea is ideas. Idea is a regular noun, so you just add s and use no apostrophe: one idea, two ideas.
Is it ideas or idea's?
For more than one idea, it is ideas with no apostrophe. Idea's, with an apostrophe, is the singular possessive (the idea's cost) or a contraction of idea is or idea has. If you only mean plural, use ideas.
When do you use ideas' with the apostrophe after the s?
Use ideas' when something belongs to more than one idea, the plural possessive. Because ideas already ends in s, you add only an apostrophe: the ideas' strengths, the ideas' impact.
Does the plural of idea ever take an apostrophe?
No. The plain plural, ideas, never takes an apostrophe. An apostrophe only appears to show possession (idea's, ideas') or in a contraction (idea's going to work).
How do you spell more than one idea?
Spell it ideas, i-d-e-a-s. Add s to idea with no apostrophe and no other change.
Is the plural of idea ideas or ideals?
It is ideas. Ideals is a different word meaning values or standards you aspire to, not the plural of idea.
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