Compare / head-to-head
Claude Fable 5.1vsClaude Opus 5.5
Claude Opus 5.5 leads 1 of 1 shared benchmark. Claude Opus 5.5 is 2.5x cheaper per token. Both offer a 1M-token context window.
Benchmarks from cited public sources; pricing from official pages; status from official provider feeds.
Shared benchmarks
0 – 1
Claude Opus 5.5 leads
Cheaper per token
Claude Opus 5.5
2.5x cheaper, input + output
Larger context
Tie
both 1M tokens
Providers
Anthropic
same provider
Claude Fable 5.1
Anthropic · released 2026-09-01
textvision
Claude Opus 5.5
Anthropic · released 2026-09-22
textvision
Quality
Benchmark matrix
1 shared · 7 only Claude Fable 5.1 · 8 only Claude Opus 5.5| Benchmark | Claude Fable 5.1 | Claude Opus 5.5 | Δ | Edge |
|---|---|---|---|---|
| Reported by both · 1 | ||||
| Terminal-Bench Science 0.1 | 52.6% ↗ | 58.7% ↗ | -6.1 pt | Claude Opus 5.5 |
| Only Claude Fable 5.1 reports · 7 | ||||
| Humanity's Last Exam (no tools) | 60.9% ↗ | not reported | — | — |
| CursorBench 3.2.0 | 73.4% ↗ | not reported | — | — |
| FrontierMath Tier 4 v2 (Epoch AI run) | 87.8% ↗epoch | not reported | — | — |
| FrontierMath Tiers 1-3 v2 (Epoch AI run) | 90.2% ↗epoch | not reported | — | — |
| GDPval-AA v2 | 1853 ↗ | not reported | — | — |
| OTIS Mock AIME 2024-2025 (Epoch AI run) | 100% ↗epoch | not reported | — | — |
| SimpleQA Verified | 70.8% ↗epoch | not reported | — | — |
| Only Claude Opus 5.5 reports · 8 | ||||
| AutomationBench 1.0.6 | not reported | 40% ↗ | — | — |
| Chartography (with tools) | not reported | 89% ↗ | — | — |
| CursorBench 4.0 | not reported | 57.8% ↗ | — | — |
| FrontierCode v1.1 (Main) | not reported | 54.4% ↗ | — | — |
| GDPval-AA v2.1 | not reported | 1846 ↗ | — | — |
| Humanity's Last Exam (with tools) | not reported | 67.7% ↗ | — | — |
| OSWorld 2.0 (partial) | not reported | 81.8% ↗ | — | — |
| Terminal-Bench 4.0 | not reported | 66.4% ↗ | — | — |
Scores tagged "epoch" or "matharena" are independent runs, used only where the lab has not published its own; ⚠ marks rows MathArena flags as released after the competition. Higher is better on every row. Δ is Claude Fable 5.1 minus Claude Opus 5.5 in the benchmark's own unit. "Not reported" means the lab has not published that figure; it is not a zero. ↗ opens the source.
Specs & pricing
Side by side
Official pricing pages and model cards| Spec | Claude Fable 5.1 | Claude Opus 5.5 | Edge |
|---|---|---|---|
| Context window | 1M tokens | 1M tokens | Tie |
| Max output | 128K tokens | 128K tokens | Tie |
| Input price / 1M | $10 ↗ | $4 ↗ | Claude Opus 5.5 |
| Output price / 1M | $50 ↗ | $20 ↗ | Claude Opus 5.5 |
| Cached input / 1M | $0.25 ↗ | $0.2 ↗ | Claude Opus 5.5 |
| Input + output / 1M Lower is cheaper. List prices; batch, tool and regional fees excluded. | $60 | $24 | Claude Opus 5.5 |
| Modalities | text · vision | text · vision | Tie |
| Released | 2026-09-01 | 2026-09-22 | — |
| Cited benchmark scores | 8 | 9 | — |
Reliability
Anthropic status
Live from /statusMore matchups
Claude Fable 5.1 vs …
Models sharing the most benchmarksMore matchups
Claude Opus 5.5 vs …
Models sharing the most benchmarksBuilt by Respan
Which one wins on your data?
Public benchmarks are a starting point. Run Claude Fable 5.1 and Claude Opus 5.5 on your own prompts with Respan evals, or route to either through one gateway key with automatic failover.