Compare / head-to-head
Claude Fable 5.1vsClaude Opus 4.8
Claude Fable 5.1 leads 5 of 5 shared benchmarks. Claude Opus 4.8 is 2x 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
5 – 0
Claude Fable 5.1 leads
Cheaper per token
Claude Opus 4.8
2x cheaper, input + output
Larger context
Tie
both 1M tokens
Provider uptime (30d)
100%
Anthropic
Claude Fable 5.1
Anthropic · released 2026-09-01
textvision
Claude Opus 4.8
Anthropic · released 2026-05-28
textvision
Quality
Benchmark matrix
5 shared · 3 only Claude Fable 5.1 · 11 only Claude Opus 4.8| Benchmark | Claude Fable 5.1 | Claude Opus 4.8 | Δ | Edge |
|---|---|---|---|---|
| Reported by both · 5 | ||||
| Humanity's Last Exam (no tools) | 60.9% ↗ | 49.8% ↗ | +11.1 pt | Claude Fable 5.1 |
| FrontierMath Tier 4 v2 (Epoch AI run) | 87.8% ↗epoch | 56.1% ↗epoch | +31.7 pt | Claude Fable 5.1 |
| FrontierMath Tiers 1-3 v2 (Epoch AI run) | 90.2% ↗epoch | 80% ↗epoch | +10.2 pt | Claude Fable 5.1 |
| OTIS Mock AIME 2024-2025 (Epoch AI run) | 100% ↗epoch | 98.3% ↗epoch | +1.7 pt | Claude Fable 5.1 |
| SimpleQA Verified | 70.8% ↗epoch | 53% ↗epoch | +17.8 pt | Claude Fable 5.1 |
| Only Claude Fable 5.1 reports · 3 | ||||
| CursorBench 3.2.0 | 73.4% ↗ | not reported | — | — |
| GDPval-AA v2 | 1853 ↗ | not reported | — | — |
| Terminal-Bench Science 0.1 | 52.6% ↗ | not reported | — | — |
| Only Claude Opus 4.8 reports · 11 | ||||
| SWE-bench Verified | not reported | 88.6% ↗ | — | — |
| GPQA Diamond | not reported | 93.6% ↗ | — | — |
| AIME 2026 | not reported | 100% ↗matharena ⚠ | — | — |
| LMArena Elo | not reported | 1452.7 ↗ | — | — |
| BrowseComp | not reported | 84.3% ↗ | — | — |
| Humanity's Last Exam (with tools) | not reported | 57.9% ↗ | — | — |
| OSWorld-Verified | not reported | 83.4% ↗ | — | — |
| SWE-bench Multilingual | not reported | 84.4% ↗ | — | — |
| SWE-bench Multimodal | not reported | 38.4% ↗ | — | — |
| SWE-Bench Pro | not reported | 69.2% ↗ | — | — |
| Terminal-Bench 2.1 | not reported | 74.6% ↗ | — | — |
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 4.8 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 4.8 | Edge |
|---|---|---|---|
| Context window | 1M tokens | 1M tokens | Tie |
| Max output | 128K tokens | 128K tokens | Tie |
| Input price / 1M | $10 ↗ | $5 ↗ | Claude Opus 4.8 |
| Output price / 1M | $50 ↗ | $25 ↗ | Claude Opus 4.8 |
| Cached input / 1M | $0.25 ↗ | $0.5 ↗ | Claude Fable 5.1 |
| Input + output / 1M Lower is cheaper. List prices; batch, tool and regional fees excluded. | $60 | $30 | Claude Opus 4.8 |
| Modalities | text · vision | text · vision | Tie |
| Released | 2026-09-01 | 2026-05-28 | — |
| Cited benchmark scores | 8 | 17 | — |
Reliability
Anthropic status
Last 60 days · refreshed daily on this page · live on /statusMore matchups
Claude Fable 5.1 vs …
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Claude Opus 4.8 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 4.8 on your own prompts with Respan evals, or route to either through one gateway key with automatic failover.