---
title: "Claude Fable 5.1 vs Claude Opus 5 — which is worth buying · Undominated.ai"
canonical: https://undominated.ai/compare/anthropic__claude-fable-5.1--vs--anthropic__claude-opus-5/
description: "Claude Fable 5.1 versus Claude Opus 5: capability, price, and whether either strictly dominates the other. Unrated stays unrated."
---

# Claude Fable 5.1 vs Claude Opus 5 — which is worth buying · Undominated.ai

> Claude Fable 5.1 versus Claude Opus 5: capability, price, and whether either strictly dominates the other. Unrated stays unrated.

# Claude Fable 5.1 versus Claude Opus 5

Neither strictly dominates the other on this workload.

 [Claude Fable 5.1](/models/anthropic__claude-fable-5.1/)

General

 **

1507.6

Effective $/M

 **

$20.00/M

 [Claude Opus 5](/models/anthropic__claude-opus-5/)

General

 **

1504.9

Effective $/M

 **

$10.00/M

| | Claude Fable 5.1 | Claude Opus 5 |
| --- | --- | --- |
| LMArena | 1507.6 | 1504.9 |
| Document | 1512.6 | 1516.3 |
| Arena | 1507.6 | 1504.9 |
| Effective $/M | $20.00 | $10.00 |
| Context | 1M | 1M |

## Questions this page answers

### Is Claude Fable 5.1 both better and cheaper than Claude Opus 5?

Neither strictly dominates the other on this workload.

### Does a missing score count as zero?

No. Unrated is not a score of zero. No quality bar is drawn for a missing score.