Model comparison
gpt-oss-20b vs Kimi K2
- Input
- $0.029 / 1M tokens
- Output
- $0.14 / 1M tokens
- Context
- 131K
- Released
- 2025-08-05
- Input
- $0.55 / 1M tokens
- Output
- $2.20 / 1M tokens
- Context
- 128K
- Released
- 2025-07-11
Kimi K2 scores higher on 3 of the 5 benchmarks both models report (the other leads on 2); gpt-oss-20b is cheaper on input tokens ($0 vs $0.6 per 1M, 19×); gpt-oss-20b has the larger context window (131K vs 128K).
Specs and pricing side by side
| Spec | gpt-oss-20b | Kimi K2 |
|---|---|---|
| Maker | OpenAI | Moonshot AI (Kimi) |
| Released | 2025-08-05 | 2025-07-11 |
| Context window | 131K | 128K |
| Max output | 131K | 128K |
| Input price | $0.029 / 1M tokens | $0.55 / 1M tokens |
| Output price | $0.14 / 1M tokens | $2.20 / 1M tokens |
| Parameters | 20.9B total / 3.6B active (MoE) | 1T total / 32B active (MoE) |
| License | Apache 2.0 | Modified MIT License |
| Weights | Open weights | Open weightssame |
| Modalities | Text | Textsame |
| Knowledge cutoff | June 2024 | not published |
Benchmarks both models report
| Benchmark | gpt-oss-20b | Kimi K2 |
|---|---|---|
| MMLU | 85.3% | 89.5% |
| GPQA Diamond | 71.5% | 75.1% |
| AIME 2024 | 92.1% | 69.6% |
| AIME 2025 | 98.7% | 49.5% |
| SWE-bench Verified | 60.7% | 65.8% |
Scores are as published by each maker or its cited source; harness, reasoning effort and date can differ between rows, so treat small gaps as ties. Sources are listed on each model page.
Which one should you pick?
Pick gpt-oss-20b if…
- You care about AIME 2024, AIME 2025 (it scores higher on 2 shared benchmarks).
- Cost matters: input tokens cost 19× less ($0 vs $0.6 per 1M).
- You need the longer context (131K vs 128K).
- Your use case is: on-device and local reasoning assistants that keep data off the cloud.
Pick Kimi K2 if…
- You care about MMLU, GPQA Diamond, SWE-bench Verified (it scores higher on 3 shared benchmarks).
- Your use case is: agentic coding assistants and automated software-engineering workflows.
FAQ
Which is better, gpt-oss-20b or Kimi K2?
Kimi K2 scores higher on 3 of the 5 benchmarks both models report (the other leads on 2); gpt-oss-20b is cheaper on input tokens ($0 vs $0.6 per 1M, 19×); gpt-oss-20b has the larger context window (131K vs 128K). The better pick depends on whether you value benchmark scores, price per token, context length or openness for your workload.
How much cheaper is gpt-oss-20b?
gpt-oss-20b: $0.029 / 1M tokens input, $0.14 / 1M tokens output. Kimi K2: $0.55 / 1M tokens input, $2.20 / 1M tokens output (list API prices as published by each maker).
What are the context windows of gpt-oss-20b and Kimi K2?
gpt-oss-20b offers 131K with up to 131K output; Kimi K2 offers 128K with up to 128K output.
Is gpt-oss-20b newer than Kimi K2?
gpt-oss-20b was released 2025-08-05; Kimi K2 was released 2025-07-11.