Compare · updated 2026-11-01
GPT-5.5 vs Kimi K3.1 Pro
GPT-5.5 is better at quick answers, writing, coding, maths, structured data, long documents, translation; Kimi K3.1 Pro is better at reasoning. Kimi K3.1 Pro is the cheaper of the two on output.
Measured quality by task
| Task | GPT-5.5 | Kimi K3.1 Pro | Better |
|---|---|---|---|
| Quick answers | 93/100 | 91/100 | GPT-5.5 |
| Writing | 94/100 | 92/100 | GPT-5.5 |
| Coding | 91/100 | 89/100 | GPT-5.5 |
| Reasoning | 79/100 | 85/100 | Kimi K3.1 Pro |
| Maths | 82/100 | 81/100 | GPT-5.5 |
| Structured data | 96/100 | 92/100 | GPT-5.5 |
| Long documents | 93/100 | 90/100 | GPT-5.5 |
| Translation | 92/100 | 91/100 | 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
| GPT-5.5 | Kimi K3.1 Pro | |
|---|---|---|
| Lab | OpenAI | Moonshot |
| Input per 1M tokens | $5 | $2 |
| Output per 1M tokens | $30 | $10 |
| Typical chat answer | $0.029 | $0.010 |
| Context window | 1M | 1.05M |
| Router picks it for | Fallback only | 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 GPT-5.5 better than Kimi K3.1 Pro?
On Nivana’s weekly evals GPT-5.5 scores higher on 7 of 8 task types (quick answers, writing, coding, maths, structured data, long documents, translation) and Kimi K3.1 Pro on 1 (reasoning). Neither is better at everything.
Which is better for coding, GPT-5.5 or Kimi K3.1 Pro?
GPT-5.5: 91/100 against 89/100 for Kimi K3.1 Pro on Nivana’s coding evals.
Which is better for writing, GPT-5.5 or Kimi K3.1 Pro?
GPT-5.5: 94/100 against 92/100 for Kimi K3.1 Pro on Nivana’s writing evals.
Which is cheaper, GPT-5.5 or Kimi K3.1 Pro?
Kimi K3.1 Pro: $10 per million output tokens against $30 for GPT-5.5, about 3.0× less. A typical chat answer costs about $0.010 on Kimi K3.1 Pro 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.