# Choosing the right Claude model: Haiku, Sonnet, Opus, or Fable

> Claude Academy · Tutorial · ~5–10 min · https://academy.claude.com/tutorials/choosing-the-right-claude-model

Claude comes in four models: Haiku, Sonnet, Opus, and Fable. Each is built for different kinds of work, and each uses your rate limit differently. Using Opus on a task Haiku could handle costs you tokens for no gain and slows you down in the process. In this guide you'll learn how to pick the Claude model that can most efficiently accomplish your task and keep you more comfortably within your rate limits.

Which models you have and how high your limit is both depend on your Claude account plan. Free includes Haiku and Sonnet; Pro and Max add Opus, Fable, and more headroom.

Meet the four models
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Claude comes in four versions. Think of them as different tools designed for different jobs.

Model	Rate limit use	Best for
Haiku	Lightest	Quick answers, summaries, and simple extraction — anything you want done instantly
Sonnet	Moderate	Coding, writing, analysis, and multi-step workflows — your versatile default
Opus	Heavy	Deep research and complex reasoning that genuinely needs sustained thinking
Fable	Heaviest	Your largest, most critical projects: long, complex tasks Claude works through with fewer check-ins

Haiku is fast and lightweight. Haiku 5.5 is our fastest model and our most capable Haiku yet, built for everyday requests. When you need quick answers to simple questions, basic summaries, or synthesis, Haiku gets it done instantly. It's also the most efficient with your rate limit.

Sonnet is the daily driver. Sonnet 5.5 brings strong reasoning to the kind of work you do every day: coding, writing, analysis, research, and complex problem-solving. It's responsive enough for real-time collaboration and capable enough that most problems won't outgrow it. It also handles computer use, vision tasks, and document and spreadsheet creation well, making it a versatile default across a wide range of work. If you're not sure which model to pick, start here.

Opus is a large reasoning specialist. Opus 5.5 is exceptional for specialized complex tasks requiring advanced reasoning. It's built for problems that genuinely need deep thinking over time. It uses more of your rate limit, so you want to reserve it for tasks that really need it. Opus is available on Pro plans and above.

Fable is the go-to for your largest, most important projects. Fable 5.1 is our most capable model, built for long, complex tasks. It can work through tasks more autonomously with fewer mid-task check-ins: describe the outcome you want, and it plans the steps and checks its own work along the way. It takes time to think through problems before answering, so responses take longer, and it uses the most of your rate limit. Fable is available on paid plans. You can select it from the model picker when a task needs it.

On some biology and security topics, Claude may switch to a different model than the one you picked, and it tells you when it does. To learn more, visit our help center.

Understanding rate limits
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Your rate limit caps how many tokens you can use in a given time window. The models consume tokens at different rates: Haiku is the lightest, Sonnet is moderate, Opus is heavy, and Fable uses the most.

Models like Haiku and Sonnet are more "efficient" with your limit: you can ask more with fewer tokens. Models like Opus and Fable use more tokens because they do more reasoning. But if you use Opus or Fable on a task that Sonnet or Haiku could handle, you may be using more of your limit unnecessarily.

One thing that helps: setting thinking and effort controls in order to customize the depth of reasoning Claude applies to a problem. The Effort setting in the model picker adjusts this directly: the default level is the right balance for most work; lower it for quicker answers that use less of your limit; save the highest setting for your hardest problems, since deeper thinking takes more time and uses more of your limit.

When to use each model
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To balance rate limits with efficiency, it's best to consider what kind of output you're looking for from Claude and choose your model accordingly. It helps to know what a useful answer would look like before you send the prompt, and to check the result in proportion to what's riding on it: a quick lookup needs only a glance, while analysis that will shape a decision deserves a closer review.

Use Haiku for:
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Simple, straightforward questions with short answers
Tasks where you just need a quick lookup or categorization
Extracting specific information from text
Simple summarization or synthesis
Anything you want done instantly without complex reasoning
Use Sonnet for:
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Writing and content creation
Coding tasks — debugging, writing new code, refactoring
Analysis that needs reasoning but isn't extremely complex
Customer support chatbots with context and nuance
Multi-step problems and workflows
Most "general purpose" work where you're not sure which model to use
Use Opus for:
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Deep research and analysis you'll question, redirect, and build on as you go
Complex work you're doing in a live, back-and-forth session, where you want each answer sooner
Problems where you've tested with Sonnet and it struggled
Use Fable for:
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Specialized tasks where accuracy is critical
Long horizon tasks with many connected steps
Outputs from dense source material: long documents, charts, technical diagrams
Work where you'd rather describe the outcome and let Claude plan the steps
Problems you've tested with Opus and it struggled
What this looks like in practice
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Let's see how this plays out with a few common tasks.

Task	Pick	Why
Summarizing articles	Haiku	Straightforward content extraction without complex reasoning
Debugging code	Sonnet	Exceptional coding capabilities, fast feedback, and clear bug identification
Analyzing complex research papers	Opus	Deep analysis across long specialized documents, including methodology critique and forward-looking insights
Building a working project from a rough idea	Fable	Plans the steps, checks its own work, and keeps working on long tasks with fewer mid-task check-ins
Try the same task on two models
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Pick a task you already know well, like summarizing a report you've read yourself. Run this prompt with Haiku first, then start a new chat with Sonnet and run it again:

Summarize the attached report in five bullet points, then flag the one claim in it you'd most want a second source for.

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Open in Claude

Compare where the answers differ, not how long they are. You've read the report, so you can judge: if Haiku's summary covers everything you would have flagged yourself, the task is Haiku-shaped. Save Sonnet, Opus, and Fable for the work where the lighter answer misses things that matter.

Choosing models over time
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Claude is always evolving, and so are the types of problems you can hand it. Each new model brings its own strengths, so the tasks worth giving Claude grow and shift with every release. When a new model comes out, try out more ambitious tasks that may have hit a ceiling in the past.

Spend a few minutes running your go-to tasks across models. If you're on the free plan, upgrading gives you access to all models and a higher rate limit. When a new model is released, you have more room to try everything.