Claude Fable 5.1 (Low, Default Fallback) vs Claude Sonnet 5.5 (Medium, Default Fallback)
Which is better for the money: Claude Fable 5.1 (Low, Default Fallback) by Anthropic or Claude Sonnet 5.5 (Medium, Default Fallback) by Anthropic? Intelligence, total benchmark cost, and end-to-end time from Artificial Analysis & other sources, snapshot 2026-10-26.
Depends on your budget
Claude Fable 5.1 (Low, Default Fallback) scores 6.0 points higher (46.8 vs 40.8) but costs 5.1× as much to run the benchmark ($3158 vs $622; flagship vs premium cost classes). They are not alternatives at one budget: pick Claude Fable 5.1 (Low, Default Fallback) when you need intelligence above 40.8, and Claude Sonnet 5.5 (Medium, Default Fall… when 40.8 is enough.
| Metric | Claude Fable 5.1 (Low, Default Fallback) | Claude Sonnet 5.5 (Medium, Default Fallback) | Difference |
|---|---|---|---|
| Intelligence (higher is better) | 46.8 | 40.8 | −12.8% Claude Sonnet 5.5 (Me… is 12.8% less intelligent |
| Total AA cost (lower is better) | $3,157.66 | $622.28 | −80.3% Claude Sonnet 5.5 (Me… is 80.3% cheaper |
| End-to-end time (lower is better) | 10.92s | 6.28s | −42.5% Claude Sonnet 5.5 (Me… is 42.5% faster |
| Price per 1M tokens (in / out) | $10.0 / $50.0 | $2.00 / $10.0 | |
| Input modalities | Text, Image | Text, Image |
Claude Sonnet 5.5 (Medium, Default Fallback) vs Claude Fable 5.1 (Low, Default Fallback): 12.8% less intelligence, 80.3% less cost to run the AA benchmark, and 42.5% faster end-to-end.
Against the frontier
- Claude Fable 5.1 (Low, Default Fallback) is off the frontier: at the same or lower cost, Kimi K3.1 Pro scores 55.10 for $3117.
- Claude Sonnet 5.5 (Medium, Default Fallback) is off the frontier: at the same or lower cost, GPT-6.1 Sol (High) scores 50.20 for $521.
Compare something else
Accept: text/markdown or ?format=md returns this page as Markdown. JSON: /api/v1/compare/claude-fable-5-1-low/claude-sonnet-5-5-medium · Markdown: /api/v1/compare/claude-fable-5-1-low/claude-sonnet-5-5-medium?format=md · llms.txt · agent skill