The Claude API offers several models, and which one you choose drives both cost and quality. Based on the official Models overview (as of June 2026), this article compares the current models' specs and pricing and lays out selection criteria by task type.
Current model lineup
Per the official docs, the main current models are below. All current Claude models support text and image input, text output, multilingual, and vision, and are available via the Claude API, AWS, Bedrock, Vertex AI, and Microsoft Foundry.
- Claude Opus 4.8 (
claude-opus-4-8) — Anthropic's most capable Opus-tier model, for complex reasoning and long-horizon agentic coding. Pricing $5 input / $25 output per MTok, 1M context, 128k max output. Supports theeffortparameter (defaults to high). - Claude Sonnet 4.6 (
claude-sonnet-4-6) — the best balance of speed and intelligence. $3 / $15, 1M context, 64k max output. Supports both extended and adaptive thinking. - Claude Haiku 4.5 (
claude-haiku-4-5-20251001, aliasclaude-haiku-4-5) — the fastest model with near-frontier intelligence. $1 / $5, 200k context, 64k max output. - Claude Fable 5 (
claude-fable-5) — Anthropic's most capable widely released model, for the most demanding reasoning and long-horizon agentic work. $10 / $50, 1M context, 128k max output. (Generally available from June 9, 2026.)
Pricing & spec comparison
Cost is priced per million tokens (MTok) of input/output. For the same task, unit price varies widely: Haiku $1/$5 → Sonnet $3/$15 → Opus $5/$25 → Fable $10/$50. Output is pricier than input, so prompt design that reduces output length directly affects cost.
- Context window: Opus 4.8, Sonnet 4.6, Fable 5 = 1M tokens; Haiku 4.5 = 200k. (On Microsoft Foundry, Opus 4.8 is 200k.)
- Max output: Opus 4.8 & Fable 5 = 128k; Sonnet 4.6 & Haiku 4.5 = 64k. (Synchronous Messages API; on the Batch API some models support up to 300k output via a beta header.)
- Thinking: Sonnet 4.6 & Haiku 4.5 support extended thinking; Opus 4.8 & Fable 5 use adaptive thinking. (Haiku 4.5 has no adaptive; Fable 5 has adaptive always on.)
- Knowledge cutoff: Opus 4.8 Jan 2026, Sonnet 4.6 Aug 2025, Haiku 4.5 Feb 2025.
Choosing by task type
The official docs advise "if unsure, start with Opus 4.8 for complex tasks." In practice, a cost/quality trade-off lens works well:
- High-volume, simple, low-latency (classification, short replies, real-time chatbots) → Haiku 4.5. Fastest and cheapest.
- Everyday production default (most coding, generation, summarization) → Sonnet 4.6. Balanced speed/intelligence/cost.
- Complex reasoning & long-horizon agentic coding → Opus 4.8. When answer quality matters most.
- Frontier-difficulty work → Fable 5. Only when the extra cost is justified.
For long documents/codebases, the 1M context (Opus, Sonnet, Fable) helps; for workflows where difficulty shifts step to step, routing different models per step is a valid approach.
Model IDs are pinned snapshots
A caveat: every Claude model ID is a pinned snapshot. IDs with a date (e.g., 20250929) are fixed to that release, and starting with the 4.6 generation the dateless format (e.g., claude-sonnet-4-6) is also a pinned snapshot, not an evergreen pointer. You can query model capabilities and token limits programmatically via the Models API (returns max_input_tokens, max_tokens, and a capabilities object).
Summary
A sensible model-selection flow: (1) gauge task difficulty and cost tolerance → (2) pick a tier among Haiku/Sonnet/Opus/Fable → (3) fine-tune by context, thinking, and output needs. To learn more, see Claude API Model IDs and Versioning and Context Window and Tokens.
This article summarizes public information from the official Anthropic docs (platform.claude.com/docs) as of June 2026. The model lineup, pricing, and specs change frequently, so always verify against the official Models overview and Pricing pages when choosing. This site is not an official Anthropic site.