Claude Fable 5.1 vs Claude Opus 5.5.
Verdict by category, tale of the tape, shared benchmarks only, and cost at three workloads — all from the tracked data.
Verdict by category
| Category | Claude Fable 5.1 | Claude Opus 5.5 | Winner |
|---|---|---|---|
| League Score | 97.3 | 96.4 | Claude Fable 5.1 |
| Coding (SWE-bench %) | — | — | — |
| Reasoning (GPQA %) | 93.7 | — | — |
| Context (tokens) | 1000000 | 1000000 | Draw |
| Speed (tok/s) | — | 75.6 | — |
| Price (blended $/1M) | $20.00 | $8.00 | Claude Opus 5.5 (cheaper) |
Tale of the tape
| Spec | Claude Fable 5.1 | Claude Opus 5.5 |
|---|---|---|
| Maker | Anthropic | Anthropic |
| Released | Sep 1, 2026 | Sep 22, 2026 |
| League Score | 97 | 96 |
| Context | 1,000,000 tokens | 1,000,000 tokens |
| Max output | 128,000 | 128,000 |
| $/1M input | $10.00 | $4.00 |
| $/1M output | $50.00 | $20.00 |
| Weights | Closed | Closed |
| Speed | — | 75.6 t/s |
Head-to-head benchmarks (shared only)
| Benchmark | Claude Fable 5.1 | Claude Opus 5.5 |
|---|---|---|
| LiveBench overall | 88.0 | 86.5 |
Cost at three workloads
| Workload | Claude Fable 5.1 | Claude Opus 5.5 |
|---|---|---|
| Light — 1M in / 250K out | $22.50 | $9.00 |
| Standard — 10M in / 2.5M out | $225.00 | $90.00 |
| Long-context — 50M in / 5M out | $750.00 | $300.00 |
The pick
Pick Claude Fable 5.1 if you want the higher overall League Score.
Pick Claude Opus 5.5 if you want the lower running cost.
All figures from the model database — sources and dates on each model page. Cost your own workload or compare a different pair.
Frequently asked questions
Which is better overall, Claude Fable 5.1 or Claude Opus 5.5?
On overall League Score they are effectively tied — Claude Fable 5.1 scores 97 and Claude Opus 5.5 scores 96. The category verdicts on this page are where the real differences live.
Which is cheaper, Claude Fable 5.1 or Claude Opus 5.5?
Claude Opus 5.5 is cheaper: $8.00 vs $20.00 blended per 1M tokens (3:1 input/output mix) — about 2.5x less per token.
Which has the bigger context window, Claude Fable 5.1 or Claude Opus 5.5?
Neither — both take 1M of context.
Are Claude Fable 5.1 and Claude Opus 5.5 open source?
Claude Fable 5.1 is closed weights — API access only; Claude Opus 5.5 is closed weights — API access only.