GPT-3.5 Turbo vs GPT-5.1
OpenAI vs OpenAI — benchmarks, pricing, and capabilities side by side.
- •GPT-5.1 has the higher intelligence index (89 vs 35.2)
- •GPT-3.5 Turbo is cheaper ($0.50 vs $1.25 per 1M input)
- •GPT-5.1 is faster
- •GPT-5.1 has a larger context window (400K)
| GPT-3.5 Turbo | GPT-5.1 | |
|---|---|---|
| Intelligence index | 35.2 | 89 |
| Developer | OpenAI | OpenAI |
| Type | LLM | LLM |
| Access | API only | API only |
| Context window | 16,385 tokens | 400,000 tokens |
| Input price | $0.50 / 1M | $1.25 / 1M |
| Output price | $1.50 / 1M | $10.00 / 1M |
| Speed | 100 tok/s | 115 tok/s |
| Released | March 1, 2023 | November 12, 2025 |
| Parameters | — | — |
| Input modalities | Text | Text, Image |
| Output modalities | Text | Text |
Shared benchmarks
GPT-3.5 Turbo
GPT-5.1
GPQA Diamond
30.8
88.1
MMLU-Pro
46.2
87