Head to head
Claude Sonnet 5.5 vs Claude Sonnet 5
Which is better, Claude Sonnet 5.5 or Claude Sonnet 5?
Claude Sonnet 5.5 finishes ahead of Claude Sonnet 5 on the index, 91.5 to 82.5, and leads on all four scores: craft, speed, control and value. Both are scored on the same rubric, in the same week, and neither placing is sponsored.
Updated
Claude Sonnet 5.5
02 of 73
91.5
Nearly the strongest model in the index, at a mid-range price. Sonnet stopped being the compromise.
Claude Sonnet 5
33 of 73
82.5
Sonnet 5.5 costs exactly the same and is far stronger. There is little reason to stay.
The four scores, side by side
| Score | Claude Sonnet 5.5 | Claude Sonnet 5 | Difference |
|---|---|---|---|
| Craft | 93 | 82 | +11 |
| Speed | 88 | 88 | — |
| Control | 90 | 89 | +1 |
| Value | 90 | 76 | +14 |
| Index score | 91.5 | 82.5 | +9.0 |
Which to pick
Claude Sonnet 5.5 is the safer pick on every axis we score. Claude Sonnet 5 earns its place in the index, but nothing in these four numbers argues for it over Claude Sonnet 5.5.
Claude Sonnet 5.5
Sonnet 5.5 is the surprise of the autumn releases. It costs the same as Sonnet 5 and scores second only to Opus 5.5 on the Artificial Analysis index, ahead of every OpenAI and Google model. Human voters rate it lower than its benchmarks suggest, which is why it sits below Opus on craft here. For coding agents, editor integrations and anything that runs all day, it is the best value at the top of the field.
Where it shines
- Second-highest Artificial Analysis score in the index, at a fifth of the Fable price
- Top-tier terminal and computer-use results
- Cheaper cached input since October, which helps long agent loops
Claude Sonnet 5
Sonnet 5 was the coding workhorse of the summer, and it still applies patches that compile and holds up over long tool-calling chains. Sonnet 5.5 now costs exactly the same per token and scores far higher on the Artificial Analysis index, so the only reason to stay is a pipeline you have tuned carefully and do not want to re-test. Anthropic lists it as a legacy model.
Where it shines
- Reliable tool calling over long chains
- Follows a repository's existing conventions
- Well understood after months of heavy production use