Claude Opus 5.5 launched: 40% cheaper, new coding SOTA — which model to pick?
Anthropic launched Claude Opus 5.5 on September 22, matching Fable 5.1 on most benchmarks at 40% of the per-token cost. Input $4/M, output $20/M — 20% cheaper than Opus 5, 30%+ faster output. SWE-bench Pro hits 89.9 (new SOTA), Terminal-Bench 4.0 hits 66.4.
Public-source compilation
Synthesized from public posts/docs. Prefer the original source for primary claims.
TL;DR
If you searched for "Claude Opus 5.5 pricing" or "Opus 5.5 vs Fable 5.1": Anthropic launched Claude Opus 5.5 on September 22, matching or beating Fable 5.1 on most benchmarks at 40% of the per-token cost. Input is $4/M tokens, output is $20/M — 20% cheaper than Opus 5, with 30%+ faster output generation.
Pricing Comparison (per million tokens, USD)
| Category | Opus 5.5 | Opus 5 | Fable 5.1 |
|---|---|---|---|
| Input | $4 | $5 | $10 |
| Output | $20 | $25 | $50 |
| Cache write (5min) | $5 | $6.25 | $12.50 |
| Cache read | $0.20 | $0.50 | $0.25 |
| Batch input/output | $2/$10 | $2.50/$12.50 | $5/$25 |
| Fast mode input/output | $8/$40 | $10/$50 | Not offered |
Key advantage: cache reads at 5% of input price (typical is 10%), a major saving for agent loops that re-read stable prefixes. The full 1M context bills at standard rate with no long-context premium.
Key Benchmark Results
| Benchmark | Opus 5.5 | Opus 5 | Fable 5.1 |
|---|---|---|---|
| SWE-bench Pro | 89.9 | 79.2 | 81.2 |
| SWE-bench Multilingual | 93.9 | 89.5 | 89.1 |
| Terminal-Bench 4.0 | 66.4 | 52.3 | 55.8 |
| FrontierCode v1.1 | 54.4 | 48.0 | 50.3 |
| Humanity's Last Exam (no tools) | 64.4 | 56.6 | 60.9 |
| OSWorld 2.0 (partial/strict) | 81.8/48.7 | 74.0/37.2 | 80.7/42.8 |
| CursorBench 4.0 | 57.8 | 46.6 | 51.8 |
Coding is the headline: SWE-bench Pro jumps +10.7 pts over Opus 5; Terminal-Bench 4.0 jumps +14.1 pts (new state of the art).
Model Specs
| Parameter | Value |
|---|---|
| Context window | 1,000,000 tokens |
| Max output (Messages API) | 128,000 tokens |
| Max output (Batch API) | 300,000 tokens |
| Knowledge cutoff | June 2026 |
| Model ID | claude-opus-5-5 |
| Platforms | Claude API, Bedrock, Vertex AI, Foundry |
| Earliest retirement | September 22, 2027 |
Note: Models since Opus 4.7 use a newer tokenizer producing ~30% more tokens for the same text. A 1M window holds ~555K English words (vs ~750K on older models).
Speed Improvements
- Output generation 30%+ faster than Opus 5
- Fast mode up to 2.5x faster (research preview, first-party API only)
- 40% less cost on typical workloads (Anthropic's claim, holds at medium/high effort)
- Customer reports: Optiver matched Opus 5 quality "in about half the turns, time and output tokens"; Kiro saw ~40% fewer calls and half the tokens
Developer Selection Guide
| Use case | Recommended | Why |
|---|---|---|
| Coding, multi-step agent tasks | Opus 5.5 | SWE-bench Pro new SOTA at 40% of Fable 5.1 cost |
| Hardest long-horizon reasoning | Fable 5.1 | OfficeQA / OfficeQA Pro still leads |
| High-frequency agent loops (cache-heavy) | Opus 5.5 | Cache reads at 5% of input price |
| Need Fast mode | Opus 5.5 | Fable 5.1 does not offer Fast |
Migration Notes
- Tokenizer change: New tokenizer since Opus 4.7 produces ~30% more tokens for the same text — recalculate budget estimates
- Model ID: Use
claude-opus-5-5directly, no date-suffixed snapshot ID - Batch API large output: Add
output-300k-2026-03-24header to unlock 300K output - Fast mode: Requires
speed: "fast"andfast-mode-2026-02-01beta header, first-party API only - US-only inference: Setting
inference_geo: "us"adds a 10% surcharge
Next Steps
- Test
claude-opus-5-5in your Claude Code or API projects, compare cost/quality vs your current model - If using agent loops, enable prompt caching and evaluate cache-read savings
- See Anthropic docs for full API reference
Related: GPT-6 Sol and Luna launched the same day with 50% API price cuts — read the coverage.
Topic hub
AI Coding Tools Hub (2026)
From Copilot pricing changes to Claude Code + DeepSeek cost-saving setups—one place to compare tools, read explainers, and follow tutorials.
Explore AI Coding Tools Hub (2026) →Monetization angle
How can you make money from this trend?
WayToClawEarn focuses on verified earn playbooks—not just news. Start from these cases.
DeepSeek + Claude Code Micro SaaS
Run multiple small products on cheap inference
Claude Code bug bounty
Productize agent skills into security services
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- How to turn off signature in VS Code Copilot AI: remove Co-Authored-by with one line of command
- Copilot vs Cursor vs Claude Code (2026): Which Should You Pick?
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