GPT-5.1 Chat vs Kimi K2 Thinking Turbo vs o1-pro
o1-pro comes out ahead, 55 to 52 and 36 on our weighted score, though GPT-5.1 Chat is 76× cheaper per token.
OpenAIGPT-5.1 Chat
52/100- ECI—
- Price$1.25 / $10.00
- Context128K
Moonshot AIKimi K2 Thinking Turbo
36/100- ECI—
- Price—
- Context262K
- Our pickOpenAI
o1-pro
55/100- ECI—
- Price$150.00 / $600.00
- Context200K
o1-pro is our pick
o1-pro is the better all-round choice, scoring 55/100 against GPT-5.1 Chat (52) and Kimi K2 Thinking Turbo (36). Kimi K2 Thinking Turbo wins on context window. The score weighs inputs & features 60%, context window 40%. None of the shared benchmarks cover every model here yet, so capability is left out of this verdict.
- CapabilityNot enough dataNo independent benchmark covers every model here yet
- Lowest priceGPT-5.1 ChatGPT-5.1 Chat $3.44 · o1-pro $262.50 per 1M tokens (3:1 blend) · Kimi K2 Thinking Turbo unpriced
- Longest contextKimi K2 Thinking TurboKimi K2 Thinking Turbo 262,144 · o1-pro 200,000 · GPT-5.1 Chat 128,000 tokens
- Widest inputsGPT-5.1 Chat and o1-proGPT-5.1 Chat: Text, Images · Kimi K2 Thinking Turbo: Text · o1-pro: Text, Images
- Self-hostingKimi K2 Thinking TurboPublishes downloadable weights
| Measure | Weight | GPT-5.1 Chat | Kimi K2 Thinking Turbo | o1-pro |
|---|---|---|---|---|
| Inputs & features | 60% | 70 | 35 | 70 |
| Context window | 40% | 24 | 37 | 32 |
| Overall | 100% | 52/100 | 36/100 | 55/100 |
Left out because at least one model lacks the data: capability and price. The remaining weights were rescaled.
Every spec in one table
Highlighted cells lead their row. Dashes mean the data is not published.
| Specification | GPT-5.1 ChatOpenAI | Kimi K2 Thinking TurboMoonshot AI | o1-proOpenAI |
|---|---|---|---|
| Capability | |||
| Capabilities Index (ECI) | — | — | — |
| ECI rank | — | — | — |
| Price per million tokens | |||
| Input | $1.25 (best) | — | $150.00 |
| Output | $10.00 (best) | — | $600.00 |
| Cached input | — | — | — |
| Blended (3:1) | $3.44 (best) | — | $262.50 |
| Long-context rate | Same rate | — | Same rate |
| Price source | Median of 2 providers | — | Official OpenAI API |
| Limits | |||
| Context window | 128,000 tokens | 262,144 tokens (best) | 200,000 tokens |
| Max output | 16,384 tokens | 262,144 tokens (best) | 100,000 tokens |
| Inputs and features | |||
| Text | Yes | Yes | Yes |
| Images | Yes | No | Yes |
| PDFs | No | No | No |
| Audio | No | No | No |
| Video | No | No | No |
| Reasoning | Yes | Yes | Yeslow · medium · high |
| Tool calling | Yes | Yes | Yes |
| Structured output | Yes | No | Yes |
| Availability | |||
| Weights | Proprietary | Open | Proprietary |
| API model ID | — | — | o1-pro |
| API providers | 2 | — | 5 (best) |
| Released | Nov 13, 2025 | Nov 6, 2025 | Mar 19, 2025 |
| Knowledge cutoff | Sep 30, 2024 | Aug 2024 | Sep 2023 |
What would a month cost?
Enter your expected volume in millions of tokens. List prices only; caching and batch discounts would lower these.
- GPT-5.1 Chat$32.50
- Kimi K2 Thinking Turbo—
- o1-pro$2,700
Which should you choose?
Which is better: GPT-5.1 Chat, Kimi K2 Thinking Turbo or o1-pro?
o1-pro is the better all-round choice, scoring 55/100 against GPT-5.1 Chat (52) and Kimi K2 Thinking Turbo (36). Kimi K2 Thinking Turbo wins on context window. The score weighs inputs & features 60%, context window 40%. None of the shared benchmarks cover every model here yet, so capability is left out of this verdict.
Which is cheaper, GPT-5.1 Chat, Kimi K2 Thinking Turbo or o1-pro?
GPT-5.1 Chat is cheaper at $1.25 input / $10.00 output per million tokens (median across 2 API providers). o1-pro costs $150.00 input / $600.00 output per million tokens (official OpenAI API price). At a typical mix of three input tokens to one output token, that is $3.44 per million tokens for GPT-5.1 Chat versus $262.50 for o1-pro (76× as much). Kimi K2 Thinking Turbo has no published per-token price.
Which scores higher on benchmarks?
There is no independent benchmark that covers all three models yet. GPT-5.1 Chat has not been scored yet, Kimi K2 Thinking Turbo has not been scored yet and o1-pro has not been scored yet.
Which is better for coding?
There are no published SWE-bench Verified results for GPT-5.1 Chat, Kimi K2 Thinking Turbo and o1-pro yet, so there is no like-for-like coding score. Test both on a sample of your own tasks. All three support tool calling for agent workflows.
Which has the bigger context window?
Kimi K2 Thinking Turbo has the largest context window at 262,144 tokens, against 200,000 for o1-pro and 128,000 for GPT-5.1 Chat. Maximum output per response: GPT-5.1 Chat up to 16,384, Kimi K2 Thinking Turbo up to 262,144, o1-pro up to 100,000 tokens.
Which can read images, PDFs, audio or video?
GPT-5.1 Chat accepts text and images; Kimi K2 Thinking Turbo accepts text; o1-pro accepts text and images. GPT-5.1 Chat handles the widest range of inputs.
Are any of these open source?
Kimi K2 Thinking Turbo publishes its weights and can be self-hosted; GPT-5.1 Chat and o1-pro is proprietary.
Which is newer?
GPT-5.1 Chat is the newest, released Nov 13, 2025. Kimi K2 Thinking Turbo came out Nov 6, 2025; o1-pro came out Mar 19, 2025. Knowledge cutoff: GPT-5.1 Chat Sep 30, 2024, Kimi K2 Thinking Turbo Aug 2024, o1-pro Sep 2023.
How do you decide the winner?
Each model gets a 0–100 score on capability (50%, independent benchmark results); price (25%, blended price per million tokens (3 input : 1 output), log scale); inputs & features (15%, image, PDF, audio and video input, tool calling, structured output and reasoning); context window (10%, maximum tokens per request, log scale). Dimensions missing for any model are dropped and the remaining weights rescaled, so every model is judged on the same evidence. Specs and prices come from public model listings and the labs’ own API pages; capability scores come from independent benchmark runs. Data updated Oct 4, 2026.
