GPT OSS 120B vs Kimi K2 Instruct
GPT OSS 120B comes out ahead, 58 to 50 on our weighted score, and it is the cheaper option too.
- Our pick
OpenAIGPT OSS 120B
58/100- ECI139.8
- Price$0.15 / $0.60
- Context131K
Moonshot AIKimi K2 Instruct
50/100- ECI139.9
- Price$0.57 / $2.30
- Context131K
Add a model
Make it a three-way comparison.
GPT OSS 120B is our pick
GPT OSS 120B is the better all-round choice, scoring 58/100 against Kimi K2 Instruct (50). It leads on price and inputs & features. The score weighs capability 50%, price 25%, inputs & features 15%, context window 10%.
- CapabilityKimi K2 InstructCapabilities Index (ECI): Kimi K2 Instruct 139.9 · GPT OSS 120B 139.8
- Lowest priceGPT OSS 120BGPT OSS 120B $0.263 · Kimi K2 Instruct $1.00 per 1M tokens (3:1 blend)
- Longest contextAbout the sameGPT OSS 120B 131,072 · Kimi K2 Instruct 131,072 tokens
- Widest inputsSame inputsGPT OSS 120B: Text · Kimi K2 Instruct: Text
- Self-hostingAll open weightsEvery model here can be downloaded and run on your own hardware
| Measure | Weight | GPT OSS 120B | Kimi K2 Instruct |
|---|---|---|---|
| CapabilityCapabilities Index (ECI) | 50% | 64 | 64 |
| Price | 25% | 74 | 48 |
| Inputs & features | 15% | 35 | 25 |
| Context window | 10% | 25 | 25 |
| Overall | 100% | 58/100 | 50/100 |
Every spec in one table
Highlighted cells lead their row. Dashes mean the data is not published.
| Specification | GPT OSS 120BOpenAI | Kimi K2 InstructMoonshot AI |
|---|---|---|
| Capability | ||
| Capabilities Index (ECI) | 139.8 | 139.9 (best) |
| ECI rank | #114 of 165 | #112 of 165 (best) |
| GPQA DiamondGraduate-level science questions | 75.8% | — |
| OTIS Mock AIME 2024–2025Competition mathematics | 88.9% | — |
| Price per million tokens | ||
| Input | $0.15 (best) | $0.57 |
| Output | $0.60 (best) | $2.30 |
| Cached input | — | — |
| Blended (3:1) | $0.263 (best) | $1.00 |
| Long-context rate | Same rate | Same rate |
| Price source | Median of 65 providers | Median of 11 providers |
| Limits | ||
| Context window | 131,072 tokens | 131,072 tokens |
| Max output | 32,768 tokens | 32,768 tokens |
| Inputs and features | ||
| Text | Yes | Yes |
| Images | No | No |
| PDFs | No | No |
| Audio | No | No |
| Video | No | No |
| Reasoning | Yes | No |
| Tool calling | Yes | Yes |
| Structured output | No | No |
| Availability | ||
| Weights | Open | OpenModified MIT |
| API model ID | — | — |
| API providers | 67 (best) | 11 |
| Released | Aug 5, 2025 | Jul 11, 2025 |
| Knowledge cutoff | Jun 2024 | — |
What would a month cost?
Enter your expected volume in millions of tokens. List prices only; caching and batch discounts would lower these.
- GPT OSS 120B$2.70
- Kimi K2 Instruct$10.30
Which should you choose?
Which is better: GPT OSS 120B or Kimi K2 Instruct?
GPT OSS 120B is the better all-round choice, scoring 58/100 against Kimi K2 Instruct (50). It leads on price and inputs & features. The score weighs capability 50%, price 25%, inputs & features 15%, context window 10%.
Which is cheaper, GPT OSS 120B or Kimi K2 Instruct?
GPT OSS 120B is cheaper at $0.15 input / $0.60 output per million tokens (median across 65 API providers). Kimi K2 Instruct costs $0.57 input / $2.30 output per million tokens (median across 11 API providers). At a typical mix of three input tokens to one output token, that is $0.263 per million tokens for GPT OSS 120B versus $1.00 for Kimi K2 Instruct (3.8× as much).
Which scores higher on benchmarks?
Kimi K2 Instruct scores higher on the Capabilities Index (ECI): Kimi K2 Instruct 139.9 (#112 of 165) and GPT OSS 120B 139.8 (#114 of 165). The confidence ranges of the top two overlap (136.3–141.6 vs 135.6–142.2), so treat the gap as small.
Which is better for coding?
There are no published SWE-bench Verified results for GPT OSS 120B and Kimi K2 Instruct yet, so there is no like-for-like coding score. On overall capability, Kimi K2 Instruct leads, which tends to carry over to coding, but test on your own codebase. Both support tool calling for agent workflows.
Which has the bigger context window?
GPT OSS 120B and Kimi K2 Instruct share the same 131,072-token context window. Maximum output per response: GPT OSS 120B up to 32,768, Kimi K2 Instruct up to 32,768 tokens.
Which can read images, PDFs, audio or video?
GPT OSS 120B accepts text; Kimi K2 Instruct accepts text. They handle the same number of input types.
Are any of these open source?
Yes, both publish their weights (Modified MIT), so you can self-host them.
Which is newer?
GPT OSS 120B is the newest, released Aug 5, 2025. Kimi K2 Instruct came out Jul 11, 2025. Knowledge cutoff: GPT OSS 120B Jun 2024.
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 Nov 2, 2026.
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