Choosing between Claude’s three models comes down to one question: how hard is the task, and how much does cost matter? Haiku, Sonnet, and Opus each occupy a distinct position — this is the complete three-way breakdown so you can route work correctly from the start.
Haiku vs Sonnet vs Opus: Full Comparison
| Spec | Haiku | Sonnet | Opus |
|---|---|---|---|
| API string | claude-haiku-4-5-20251001 | claude-sonnet-4-6 | claude-opus-4-6 |
| Input price (per M tokens) | ~$1.00 | ~$3.00 | ~$5.00 |
| Output price (per M tokens) | ~$5.00 | ~$5.00 | ~$25.00 |
| Context window | 200K | 1M | 1M |
| Speed | ⚡ Fastest | ⚡ Fast | 🐢 Slower |
| Reasoning depth | Good | Excellent | Maximum |
| Writing quality | Good | Excellent | Maximum |
| Cost vs Sonnet | ~4× cheaper | — | ~5× more expensive |
Claude Haiku: The Volume Model
Haiku is optimized for tasks that are high in quantity but low in complexity — situations where you’re running the same operation hundreds or thousands of times and cost per call is a real constraint. Classification, extraction, summarization, metadata generation, routing logic, short-form responses, and real-time features where latency matters more than depth.
The output quality on constrained tasks is strong. Where Haiku shows its limits is on open-ended, nuanced work — multi-step reasoning, long-form writing where voice consistency matters, or problems with competing constraints. For those, Sonnet is the right call.
Claude Sonnet: The Default
Sonnet handles the vast majority of professional work at a quality level that’s indistinguishable from Opus for most tasks. Writing, analysis, research, coding, summarization, strategy — Sonnet does all of it well. It’s the model to start with and the one most people should use as their production default.
The gap between Sonnet and Opus shows on genuinely hard tasks: novel multi-step reasoning, edge cases in complex code, nuanced judgment in ambiguous situations, or extended agentic sessions where small quality differences compound. For everything else, Sonnet is the right choice and a fraction of the cost.
Claude Opus: The Specialist
Opus earns its premium on tasks where maximum capability is the only variable that matters and cost is secondary. Complex legal or technical analysis, research synthesis across conflicting sources, architectural decisions with long-term consequences, extended agentic sessions, and any task where you’ve tried Sonnet and felt the output was a notch below what the problem deserved.
The practical test: if Sonnet’s output on a task is good enough, use Sonnet. Only reach for Opus when you’ve genuinely hit Sonnet’s ceiling on a specific problem. Most professionals do this on a small fraction of their actual workload.
The Decision Framework
Use Haiku when: same operation at high volume, output is constrained/structured, cost and speed matter, real-time latency required.
Use Sonnet when: any standard professional task — writing, coding, analysis, research. This should be your default 90% of the time.
Use Opus when: the task is genuinely hard, involves novel reasoning, Sonnet’s output wasn’t quite right, or quality is the only variable that matters regardless of cost.
For full pricing details, see Anthropic API Pricing. For a Haiku deep-dive, see Claude Haiku: Pricing, Use Cases, and API String. For the Opus vs Sonnet head-to-head, see Claude Opus vs Sonnet.
Frequently Asked Questions
What’s the difference between Claude Haiku, Sonnet, and Opus?
Haiku is fastest and cheapest — built for high-volume, constrained tasks. Sonnet is the balanced production default with excellent quality across most professional work. Opus is the most capable model for complex reasoning — about 5× more expensive than Sonnet on input tokens.
Which Claude model should I use?
Start with Sonnet for almost everything. Switch to Haiku when you’re running the same operation at high volume and cost matters. Switch to Opus when Sonnet’s output on a specific task isn’t quite at the level the problem requires.
Is Claude Haiku good enough for most tasks?
For structured, constrained tasks — yes, Haiku is strong. For open-ended writing, complex reasoning, or work requiring nuanced judgment, Sonnet is the right step up. The cost savings from Haiku are meaningful at scale, making it the right choice when the task fits its strengths.
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