Claude API Pricing 2026:
Fable 5.1, Opus 5.5, Sonnet 5.5 & Haiku 4.5 Costs

Anthropic's current Claude lineup has four tiers: Claude Fable 5.1, its most capable widely released model, for the hardest reasoning and long-horizon agentic work; Claude Opus 5.5 for complex analysis and agents; Claude Sonnet 5.5 as the everyday production default; and Claude Haiku 4.5 for high-volume, cost-sensitive workloads. Fable 5.1, Opus 5.5 and Sonnet 5.5 all have a 1 million token context window; Haiku 4.5 has 200K.

Claude API Standard Pricing 2026

Previous-Generation Claude Models Still on the API

For new projects, Opus 5.5 and Sonnet 5.5 are cheaper than the models they replace, so migrating usually lowers the bill as well as improving quality.

Prompt Caching Pricing

Prompt caching bills repeated prompt prefixes — system prompts, tool definitions, shared documents — at a fraction of the normal input price. Cache reads cost:

Writing a prompt into the cache costs more than a normal input token, so caching pays off when the same prefix is reused across many requests.

Batch API Pricing

Anthropic's Message Batches API gives a 50% discount for non-real-time workloads (classification, data processing, evals). Batches complete within 24 hours.

Claude vs OpenAI: Quick Price Comparison

GPT-6 Luna is far cheaper than Haiku 4.5 for simple, high-volume tasks. In the middle of the market Sonnet 5.5 and GPT-6.1 Sol cost exactly the same, and Opus 5.5 costs less than half of GPT-6 Astra. OpenAI prices above 272K input tokens double for input; check long-context rates before sending very large prompts.

Which Claude Model Should You Choose?

Real-World Cost Examples

Customer Support Bot — 50,000 conversations/month

• System prompt: 2,000 tokens (cached after the first call)
• Per conversation: 500 tokens fresh input + 300 tokens output
• Sonnet 5.5 without caching: 125M input × $2 + 15M output × $10 = ~$400/month
• Sonnet 5.5 with prompt caching: 100M cached × $0.20 + 25M × $2 + $150 output = ~$220/month
• Savings: about 45% overall — caching removes 90% of the system-prompt cost, and output tokens make up most of what remains

Document Analysis Pipeline — 10,000 docs/month

• Average: 5,000 tokens input + 800 tokens output (50M input, 8M output per month)
• Haiku 4.5: $50 input + $40 output = $90/month
• Sonnet 5.5: $100 input + $80 output = $180/month
• Opus 5.5: $200 input + $160 output = $360/month

API Access

• Sign up at console.anthropic.com — no approval process required
• Pay-as-you-go billing, no monthly minimum
• Enterprise: custom terms for high-volume spend — contact Anthropic sales

Frequently Asked Questions

Is Claude Sonnet 5.5 the best default production model?

For most teams, yes. It handles complex tasks at $2/M input and $10/M output, and its 1M-token context handles large documents without chunking. Haiku 4.5 is the better choice when volume is high and cost is the main constraint.

Does Claude batch processing reduce cost?

Yes — Anthropic's Message Batches API gives a 50% discount on input and output tokens. Batches complete within 24 hours, which makes them a good fit for classification, evals and other pipelines that are not latency-sensitive.

Is Opus 5.5 more expensive than Opus 4.6?

No. Opus 5.5 is $4/M input and $20/M output, compared with $5/$25 for Opus 4.6, Opus 4.7, Opus 4.8 and Opus 5. Sonnet 5.5 is also cheaper than Sonnet 4.6 ($2/$10 vs $3/$15).

When is Haiku 4.5 worth it over GPT-6 Luna?

GPT-6 Luna ($0.10/M input, $0.50/M output) is ten times cheaper per token than Haiku 4.5 ($1/$5). Haiku can still win on total cost if it needs fewer retries or shorter prompts for your task, so benchmark both on real traffic before choosing.

Which Claude model is best for RAG or coding?

Sonnet 5.5 is the default for both. For RAG, its 1M context window can hold large document sets; for coding, it handles complex multi-file tasks and follows detailed instructions reliably. Opus 5.5 and Fable 5.1 are worth the premium for the longest, most complex reasoning or research tasks.