Compare · updated 2026-11-01
Claude Sonnet vs GPT-5.5
Claude Sonnet is better at coding, reasoning, maths; GPT-5.5 is better at quick answers, writing, structured data, long documents, translation. Claude Sonnet is the cheaper of the two on output.
Measured quality by task
| Task | Claude Sonnet | GPT-5.5 | Better |
|---|---|---|---|
| Quick answers | 85/100 | 93/100 | GPT-5.5 |
| Writing | 93/100 | 94/100 | GPT-5.5 |
| Coding | 94/100 | 91/100 | Claude Sonnet |
| Reasoning | 90/100 | 79/100 | Claude Sonnet |
| Maths | 84/100 | 82/100 | Claude Sonnet |
| Structured data | 88/100 | 96/100 | GPT-5.5 |
| Long documents | 90/100 | 93/100 | GPT-5.5 |
| Translation | 86/100 | 92/100 | GPT-5.5 |
Quality is Nivana’s measured score for each kind of task, from weekly pairwise evals judged by models from several labs. Prices are live AI Gateway list prices per million tokens. Updated 2026-11-01. How this is measured.
Price and context
| Claude Sonnet | GPT-5.5 | |
|---|---|---|
| Lab | Anthropic | OpenAI |
| Input per 1M tokens | $2 | $5 |
| Output per 1M tokens | $10 | $30 |
| Typical chat answer | $0.010 | $0.029 |
| Context window | 1M | 1M |
| Router picks it for | 3 of 24 request types | Fallback only |
Which should you use?
Use the one that wins the kind of work you do most, unless the price gap outweighs the quality gap for easy requests. Or don’t choose: Nivana scores both, and the rest of the pool, on every request and sends it to whichever is best for that request.
Questions
Is Claude Sonnet better than GPT-5.5?
On Nivana’s weekly evals Claude Sonnet scores higher on 3 of 8 task types (coding, reasoning, maths) and GPT-5.5 on 5 (quick answers, writing, structured data, long documents, translation). Neither is better at everything.
Which is better for coding, Claude Sonnet or GPT-5.5?
Claude Sonnet: 94/100 against 91/100 for GPT-5.5 on Nivana’s coding evals.
Which is better for writing, Claude Sonnet or GPT-5.5?
GPT-5.5: 94/100 against 93/100 for Claude Sonnet on Nivana’s writing evals.
Which is cheaper, Claude Sonnet or GPT-5.5?
Claude Sonnet: $10 per million output tokens against $30 for GPT-5.5, about 3.0× less. A typical chat answer costs about $0.010 on Claude Sonnet and $0.029 on GPT-5.5.
Or let the router pick, per request
Nivana sends every message to the model that scores best for it, sets how hard it thinks, and tells you which one answered. 2,000 free credits to start, no card.