Very long inputs
Choose Claude Fable 5.1
Claude Fable 5.1 reads up to 1M tokens per request, against 200k for Claude Opus 4.
Claude Fable 5.1 vs Claude Opus 4: price, context and capabilities
Choose Claude Fable 5.1 for very long inputs and the latest release; on the other points the two are level or the data is missing.
In short
- Claude Opus 4 has been retired; Claude Fable 5.1 is the one you can still call.
- A price comparison is not possible: one of them has no comparable published price.
- Claude Fable 5.1 reads more per request: 1M tokens against 200k.
- Claude Fable 5.1 is the newer model (September 2026, against May 2025).
Which should you choose?
Each answer below comes straight from the published prices, specifications and independent benchmark results.
Latest release
Choose Claude Fable 5.1
Claude Fable 5.1 is the newer release (September 2026, against May 2025 for Claude Opus 4).
Specifications side by side
| Claude Fable 5.1 | Claude Opus 4 | |
|---|---|---|
| Provider | Anthropic | Anthropic |
| Category | Language models | Language models |
| Status | Generally available | Retired |
| Headline price | $20.00 / 1M tokens | $30.00 / 1M tokens |
| Input | $10.00 / 1M tokens | $15.00 / 1M tokens |
| Output | $50.00 / 1M tokens | $75.00 / 1M tokens |
| Cached input | $0.25 / 1M tokens | $1.50 / 1M tokens |
| Context window | 1M | 200k |
| Max output | 128k | No data |
| Released | September 2026 | May 2025 |
| Knowledge cutoff | June 2026 | No data |
| Licence | Proprietary | Proprietary |
| Capabilities | Vision, Reasoning, Tool calling, Structured output, Prompt caching, Batch API | Vision, Reasoning, Tool calling, Structured output, Prompt caching, Batch API |
| API model id | claude-fable-5-1 | claude-opus-4-20250514 |
Benchmarks side by side
Leader in bold.
| Benchmark | Claude Fable 5.1 | Claude Opus 4 |
|---|---|---|
| Intelligence Index | 53.4 | No data |
| SciCode | 63.1% | No data |
| GPQA Diamond | 93.7% | No data |
| Humanity's Last Exam | 59.1% | No data |
| Long-context reasoning (AA-LCR) | 85.3% | No data |
Independent evaluations by Artificial Analysis, run the same way for every model, at the reasoning setting shown. Percentages unless marked as an index.
Frequently asked questions
Should I choose Claude Fable 5.1 or Claude Opus 4?
Choose Claude Fable 5.1 for very long inputs and the latest release; on the other points the two are level or the data is missing.
Which is cheaper, Claude Fable 5.1 or Claude Opus 4?
A price comparison is not possible: one of them has no comparable published price.
Which has the larger context window, Claude Fable 5.1 or Claude Opus 4?
Claude Fable 5.1 reads more per request: 1M tokens against 200k.
What is the difference between Claude Fable 5.1 and Claude Opus 4?
Claude Fable 5.1 is made by Anthropic and Claude Opus 4 by Anthropic. Claude Opus 4 has been retired; Claude Fable 5.1 is the one you can still call. A price comparison is not possible: one of them has no comparable published price. Claude Fable 5.1 reads more per request: 1M tokens against 200k. Claude Fable 5.1 is the newer model (September 2026, against May 2025).
Which is newer, Claude Fable 5.1 or Claude Opus 4?
Claude Fable 5.1 was released on September 2026 and Claude Opus 4 on May 2025.