Claude Fable 5.1 (Medium, Default Fallback) vs Claude Sonnet 5 (Medium)
Which is better for the money: Claude Fable 5.1 (Medium, Default Fallback) by Anthropic or Claude Sonnet 5 (Medium) by Anthropic? Intelligence, total benchmark cost, and end-to-end time from Artificial Analysis & other sources, snapshot 2026-10-25.
Depends on your budget
Claude Fable 5.1 (Medium, Default Fallb… scores 20.8 points higher (48.9 vs 28.1) but costs 3.3× as much to run the benchmark ($3983 vs $1218; flagship vs premium cost classes). They are not alternatives at one budget: pick Claude Fable 5.1 (Medium, Default Fallb… when you need intelligence above 28.1, and Claude Sonnet 5 (Medium) when 28.1 is enough.
| Metric | Claude Fable 5.1 (Medium, Default Fallback) | Claude Sonnet 5 (Medium) | Difference |
|---|---|---|---|
| Intelligence (higher is better) | 48.9 | 28.1 | −42.5% Claude Sonnet 5 (Medi… is 42.5% less intelligent |
| Total AA cost (lower is better) | $3,983.28 | $1,218.17 | −69.4% Claude Sonnet 5 (Medi… is 69.4% cheaper |
| End-to-end time (lower is better) | 14.35s | 9.27s | −35.4% Claude Sonnet 5 (Medi… is 35.4% faster |
| Price per 1M tokens (in / out) | $10.0 / $50.0 | $2.00 / $10.0 | |
| Input modalities | Text, Image | Text, Image |
Claude Sonnet 5 (Medium) vs Claude Fable 5.1 (Medium, Default Fallback): 42.5% less intelligence, 69.4% less cost to run the AA benchmark, and 35.4% faster end-to-end.
Against the frontier
- Claude Fable 5.1 (Medium, Default Fallback) is off the frontier: at the same or lower cost, Kimi K3.1 Pro scores 55.10 for $3117.
- Claude Sonnet 5 (Medium) is off the frontier: at the same or lower cost, GPT-6.1 Sol (Max) scores 51.80 for $1082.
Compare something else
Accept: text/markdown or ?format=md returns this page as Markdown. JSON: /api/v1/compare/claude-fable-5-1-medium/claude-sonnet-5-medium · Markdown: /api/v1/compare/claude-fable-5-1-medium/claude-sonnet-5-medium?format=md · llms.txt · agent skill