Bad is an adjective and describes a noun. Badly is an adverb and describes a verb. So you write a bad decision but he sang badly. After linking verbs the adjective is correct, which is why I feel bad is the standard form — and why I feel badly, despite sounding more careful, is the one people argue about.
The basic rule
Ask what the word is describing. A person or thing takes bad. An action takes badly.
- That was a bad call. — describes the call.
- The umpire called it badly. — describes how he called it.
- She’s a bad driver. — describes the driver.
- She drives badly. — describes the driving.
Badly cannot sit in front of a noun. A badly decision is not possible in English, while a badly worded decision is fine — there badly is describing worded, not the decision.
The exception: linking verbs
Linking verbs connect the subject to a description of it rather than to an action, and they take an adjective. The common ones are be, seem, appear, become, and the sense verbs look, feel, sound, taste, smell.
- The milk smells bad. — the milk is bad, not the smelling.
- This looks bad for the company.
- The audio sounds bad on the second take.
The test: if you can swap the verb for is and the sentence still works, it is a linking verb and you want bad. The milk is bad works, so the milk smells bad is right.
Some verbs go both ways, and the choice changes the meaning completely. The dog smells bad means the dog needs a wash. The dog smells badly means its sense of smell is poor — here smell is an action the dog performs.
“I feel bad” or “I feel badly”?
I feel bad is the form no one will question. Feel is working as a linking verb, exactly as in I feel tired or I feel ready, and nobody says I feel tiredly.
I feel badly is more complicated than it is usually made out to be. Taken literally it describes poor technique at touching things. But it has been used by educated speakers for well over a century, it appears in major dictionaries as an accepted variant for the emotional sense, and it most likely survives because bad sounds too blunt for expressing regret.
What that means in practice:
- In writing, use I feel bad. It is standard, and no editor or examiner will mark it.
- I feel badly about it is common in speech and is not an error worth correcting in someone else.
- If you want to avoid the question entirely, I regret or I’m sorry about sidesteps it.
“Badly” also means “very much”
This is the sense most guides skip. With verbs of wanting and needing, badly does not mean “in a poor manner” at all — it means intensely.
- We badly need a second reviewer.
- She wanted the transfer badly.
- The bridge is badly in need of repair.
It works the same way with past participles describing damage: badly damaged, badly injured, badly overdrawn. In all of these, badly is an intensifier rather than a judgment of quality.
He wants it bad uses bad as an adverb. It is common in American speech and song lyrics, and it is nonstandard in writing.
Side-by-side
| Sentence | What it means |
|---|---|
| I feel bad. | I’m sorry, or I’m unwell. |
| I feel badly. | Literally: my sense of touch is poor. Widely used for regret. |
| He looks bad. | He appears unwell, or the situation reflects poorly on him. |
| He looks badly. | He is poor at looking. Almost never what you mean. |
| The team played bad. | Nonstandard in writing. |
| The team played badly. | Standard. |
| She needs it bad. | Informal speech. |
| She needs it badly. | Standard, meaning very much. |
Comparatives: both become “worse”
Both words are irregular and share the same forms:
- bad → worse → worst
- badly → worse → worst
There is no badder or baddest in standard English. Both exist in slang, where baddest deliberately reverses the meaning into a compliment, but neither belongs in ordinary writing. As with good and well, the adjective-adverb question disappears at the comparative: she did worse than expected and a worse result are both correct.
Hyphens: “badly written,” not “badly-written”
Compounds formed with an adverb ending in -ly do not take a hyphen, even before a noun:
- Correct: a badly written report, a badly damaged roof.
- Wrong: a badly-written report.
This is worth noticing because the opposite pair behaves differently. Well does not end in -ly, so a well-written report does take the hyphen before the noun. The two rules look inconsistent and are not: the -ly ending already signals that the word is modifying the participle, so the hyphen has no work to do.
Common questions
Is “I feel badly” wrong?
Not exactly, but I feel bad is the safer choice. The traditional objection is that feel here is a linking verb and needs an adjective. Dictionaries record feel badly as established usage for the emotional sense, so it is defensible — it simply invites the argument, and I feel bad never does.
Is it “my bad” or “my badly”?
My bad. It is a fixed informal phrase using bad as a noun, roughly meaning “my mistake.” My badly is not English. The expression is casual and out of place in professional writing.
“The results were bad” or “badly”?
Bad. Were is a form of be, the clearest linking verb there is, so the adjective follows. If you want the adverb, attach it to a real verb instead: the trial went badly.
Can “bad” ever be an adverb?
In informal speech, yes — we lost bad, she wants it bad. Dictionaries label this nonstandard or informal, and it reads as dialect or as deliberate casualness in writing. Badly is the form to use when the register matters.