Opus, Sonnet, Haiku: which Claude model should you choose?

Claude Fable — maximum capability

Anthropic describes Fable as its most capable widely released model. Reach for it when a task demands the highest available capability and cost is secondary. Available through the API and the major clouds.

Claude Opus — the versatile top tier

Opus is the top tier for demanding everyday work: complex reasoning, deep analysis, agentic coding, high-stakes tasks. Anthropic recommends it as the starting point for complex agentic coding and enterprise workloads.

Claude Sonnet — the balance

Sonnet is the workhorse: the best balance of performance, speed and cost. For the vast majority of everyday uses — writing, summarizing, routine code — it's the recommended default.

Claude Haiku — the fastest

Haiku is the fastest and most affordable: ideal for volume, real-time, classification and simple tasks at scale, where latency and cost come first.

How to choose in practice

Simple rule: start with Sonnet. If the task struggles (reasoning, hard code), move up to Opus, then to Fable if you genuinely need the ceiling. If you process large volumes or need minimal latency, drop to Haiku. Separately: Mythos, aimed at defensive cybersecurity, is invitation-only — there is no self-serve sign-up. Version numbers change each generation — follow the Models category of our feed.

Which Claude model is the most powerful?

Fable, which Anthropic describes as its most capable widely released model. Opus remains the versatile top tier and the recommended default for complex agentic coding.

Which Claude model should I choose by default?

Sonnet: the best balance of performance, speed and cost for most uses.

Which Claude model is the cheapest?

Haiku, the fastest and most affordable, built for volume and real-time.

Difference between Opus and Sonnet?

Opus is more capable (but slower/pricier) for hard tasks; Sonnet is the everyday balance.