Quick and quickly both express speed, short duration, or little delay, but they normally perform different jobs in a sentence. That is why the choice in quick vs quickly depends less on meaning and more on what the word describes.
Use quick mainly as an adjective. It describes a noun, pronoun, or subject: a quick meeting, a quick answer, or the meeting was quick.
Use quickly as an adverb. It describes how or how soon an action happens: the meeting ended quickly or she answered quickly.
Informal speech sometimes uses quick as an adverb, as in “Come quick.” That form is common in conversation, but quickly is clearer in careful writing.
Quick Answer
Use quick when describing a person, thing, event, or response:
- a quick call
- The call was quick.
Use quickly when describing an action:
- She called quickly.
- The problem spread quickly.
Quick can also act as an informal adverb in phrases such as “Come quick.” In business, academic, school, and other polished writing, quickly is the safer adverb.
Why People Confuse Them
Both words relate to speed and promptness. Many English adverbs also add -ly to an adjective, so the pair appears simple.
People also hear “real quick,” “come quick,” and “get rich quick.” These forms are natural in casual US speech, though quickly is more neutral in careful prose.
The word fast adds to the confusion because it can work as both an adjective and an adverb:
- a fast car
- drive fast
Before a noun, quick is standard: a quick response. After an action verb, quickly is normally preferred: respond quickly.
Linking verbs also confuse writers. In “The test was quick,” quick describes the test, not the action of being.
Key Differences At A Glance
| Feature | Quick | Quickly |
|---|---|---|
| Primary role | Adjective | Adverb |
| Usually describes | A noun, pronoun, or subject | An action, change, or development |
| Before a noun | a quick reply | Not normally used |
| After a linking verb | The reply was quick. | Not used for this meaning |
| After an action verb | Informal in some uses | Neutral and standard |
| Other roles | Limited adverb and noun uses | Normally an adverb |
| Register | Neutral as an adjective; conversational as an adverb | Neutral in most contexts |
| Context | Best Choice | Why |
| Before a noun | quick | It describes the noun. |
| After a linking verb | quick | It describes the subject. |
| Describing how an action happens | quickly | It modifies the action. |
| Formal request | quickly | It sounds polished and neutral. |
| Casual command | quick or quickly | Quick is informal; quickly is neutral. |
| Short event or response | quick | It describes duration or promptness. |
| Rapid change or movement | quickly | It explains how the change happens. |
Meaning and Usage Difference
Quick usually characterizes a person, thing, response, event, or condition. It may mean fast, prompt, brief, mentally sharp, or easily provoked, depending on context.
- We need a quick solution.
- He is a quick learner.
- The change was quick.
- She is quick to notice errors.
In “a quick solution,” quick modifies solution. In “The change was quick,” it describes the subject after was.
Quickly tells readers that an action happens rapidly, promptly, soon, or without much delay.
- We need to solve it quickly.
- He learns quickly.
- The situation changed quickly.
- She quickly noticed the error.
Quick can describe duration, promptness, or mental ability. Quickly can describe decisions, recovery, understanding, or replies—not only movement.
The structure matters. “The answer was quick” describes the answer. “She answered quickly” describes the act of answering.
Tone, Context, and Formality
Adjectival quick is standard and neutral in almost every setting:
- a quick email
- a quick check
- The response was quick.
Quickly is also neutral. It works naturally in conversation, workplace messages, school assignments, reports, and formal documents.
- Please respond quickly.
- The issue was resolved quickly.
- Sales increased quickly during the first week.
Adverbial quick is more conversational:
- Come quick.
- Let me check real quick.
- Reply quick when you see this.
These forms can sound direct or relaxed. In edited or professional writing, quickly is safer.
A direct replacement is not always smooth. “Can I ask you a quick question?” often sounds better than “Can I ask you something quickly?”
Commands and ads may favor forceful phrases such as “Act quick.” In polished prose, “Act quickly” is more neutral.
Which One Should You Use?
Identify what the word describes.
Use quick when it answers “What kind?” about a noun:
- What kind of response? A quick response.
- What kind of stop? A quick stop.
Use quickly when it answers “How?” about an action:
- How did they respond? They responded quickly.
- How did the software load? It loaded quickly.
Watch for linking verbs such as be, seem, become, feel, look, and remain. A word after a verb is not always an adverb.
- The response was quick.
- She became quick at spotting errors.
- The process seemed quick.
In these sentences, quick describes the subject rather than the verb.
For formal writing, replace uncertain adverbial quick with quickly or rewrite the sentence:
- Casual: Please reply quick.
- Polished: Please reply quickly.
- Alternative: Please send a quick reply.
Use adverbial quick only as a deliberate informal choice.
When One Choice Sounds Wrong
Quickly cannot normally describe a noun directly:
- Incorrect: I need a quickly answer.
- Correct: I need a quick answer.
It also does not work as a subject description after a linking verb:
- Incorrect: She is a quickly learner.
- Correct: She is a quick learner.
- Incorrect: The meeting was quickly.
- Correct: The meeting was quick.
Quick after an action verb may sound compressed or conversational:
- Informal: Finish it quick.
- Neutral: Finish it quickly.
Both can be correct when they describe different things: “The process was quick” describes the process, while “The process ended quickly” describes its ending.
“Make it quick” asks for a brief task or event. “Do it quickly” asks for fast performance.
Common Mistakes
Mistake: Using quickly before a noun
- Wrong: a quickly lunch
- Right: a quick lunch
A noun needs the adjective quick.
Mistake: Using quickly after be to describe the subject
- Wrong: The repair was quickly.
- Right: The repair was quick.
Quick describes the repair.
Mistake: Using informal quick in formal prose
- Casual: Please submit the form quick.
- Polished: Please submit the form quickly.
The second suits careful writing.
Mistake: Assuming every word after a verb must be an adverb
- He is quick.
- He moves quickly.
Quick follows a linking verb and describes he. Quickly modifies moves.
Mistake: Writing fastly
- Wrong: She runs fastly.
- Right: She runs fast.
Fast already works as an adverb. This does not mean quick follows the same pattern in every context.
Mistake: Using real quick everywhere
“Real quick” is common in conversation, but it may sound too casual in a report, application, or formal email. Use quickly, briefly, or a quick plus a noun when greater polish is needed.
Everyday Examples
Work
We need a quick decision before noon.
Please decide quickly so the team can proceed.
Thank you for your quick reply.
Thank you for replying quickly.
Technology
The update included a quick fix.
The app loaded quickly after the update.
School
She is a quick learner.
She learns new formulas quickly.
Travel
We made a quick stop for gas.
We stopped quickly when the warning light appeared.
Home
I took a quick shower.
I showered quickly because I was late.
Conversation
Can I ask a quick question?
Can we talk quickly before you leave?
Emergency
The paramedic made a quick assessment.
The paramedic reacted quickly.
Informal Speech
Come quick!
Neutral alternative: Come quickly!
A quick action is not automatically careless; context determines whether the speed is useful or rushed.
Dictionary-Style Word Details
Verb
- Quick: Quick is not commonly used as a verb in standard modern US English. The usual verb is quicken, meaning to make something faster or to become faster.
- Quickly: Quickly does not function as a verb. It is an adverb.
Noun
- Quick: Quick has limited noun uses. It can refer to sensitive flesh under a fingernail, a person’s deepest feelings, or the vital center of something. It also appears in the historical expression “the quick and the dead,” where quick means living.
- Quickly: Quickly does not normally function as a noun.
Synonyms
- Quick: Sense-matched alternatives include brief for short duration, prompt for little delay, rapid or swift for fast movement or change, and sharp or agile for mental ability.
- Quickly: Closest plain alternatives include rapidly, swiftly, speedily, promptly, soon, and sometimes fast.
Brief can replace quick in “a brief meeting,” but not quickly in “She answered quickly.” Common speed-related opposites are slow and slowly.
Example Sentences
Quick
- She took a quick look at the schedule.
- We received a quick response from the support team.
- The repair was quick but effective.
- He is quick to notice small errors.
- Please be quick; the store is closing.
Quickly
- She quickly checked the schedule.
- The support team responded quickly.
- The technician repaired the issue quickly.
- He quickly noticed the missing date.
- The store filled quickly after the doors opened.
Word History
- Quick: Quick comes through Middle English from Old English cwic, an older word meaning living or alive. That earlier sense remains visible in references to sensitive living flesh and in “the quick and the dead.”
- Quickly: Quickly developed from quick plus the adverb-forming suffix -ly. Its form reflects the common English pattern of building an adverb from an adjective.
Modern usage still depends mainly on grammatical function and context.
Phrases Containing
Quick
- a quick question
- a quick answer
- a quick look
- quick thinking
- quick to respond
- make it quick
- quick as a flash
- cut to the quick
- the quick and the dead
- quick and easy
Quickly
- respond quickly
- move quickly
- finish quickly
- act quickly
- as quickly as possible
- quickly realized
- quickly became clear
- quickly changed
Several quick expressions are idioms; most quickly examples are ordinary verb-adverb combinations.
FAQs
Is it quick or quickly?
Both are correct. Use quick to describe a noun or subject, and quickly to describe an action.
Example: We had a quick lunch, but we ate quickly.
Can quick be an adverb?
Yes. Quick can act as an adverb in informal expressions, though quickly is more neutral in careful writing.
Example: “Come quick” is conversational; “Come quickly” fits any register.
Is “come quick” correct?
It is common in informal English. Use “come quickly” in formal or edited writing.
Example: Come quickly; we need your help.
Why is “be quick” correct?
Be is a linking verb, and quick describes the person being addressed. It is not describing how the action of being happens.
Example: Be quick, or we will miss the bus.
Is “real quick” grammatically correct?
It is an established informal US expression. In polished prose, use quickly, briefly, or rewrite with quick before a noun.
Example: “Let me check real quick” can become “Let me do a quick check.”
Should I write “reply quick” or “reply quickly”?
Use “reply quickly” in careful writing. “Reply quick” sounds conversational.
Example: Please reply quickly before the deadline.
Is it “a quick response” or “a quickly response”?
“A quick response” is correct because response is a noun and needs an adjective.
Example: Her quick response prevented a delay.
What is the difference between “The response was quick” and “They responded quickly”?
The first describes the response; the second describes the action.
Example: The response was quick because they responded quickly.
Is quicker or more quickly correct?
Quicker normally works as the comparative adjective. More quickly is the clearest comparative adverb in careful writing.
Example: This route is quicker, but the train moves more quickly.
Are quick and quickly interchangeable?
Only in limited informal adverbial contexts. They are not interchangeable before nouns or after linking verbs.
Example: “a quick answer” is correct, while “a quickly answer” is not.
Conclusion
Use quick to describe a noun, pronoun, or subject. Use quickly to explain how or how soon an action happens.
A quick answer is short or prompt. The answer was quick describes the answer itself. She answered quickly describes the action.
In quick vs quickly, the most reliable rule is to identify what the word modifies. Informal adverbial quick is common, but quickly remains the clearer choice when polish and precision matter.
