gpt-oss-20b vs Kimi K3
gpt-oss-20b (OpenAI) and Kimi K3 (Moonshot) compared on benchmarks, pricing, context window, and use-case rankings.
- Kimi K3 leads on overall intelligence (ECI 158 vs 138).
- gpt-oss-20b is cheaper on input tokens — $0.02 vs $1.44 per 1M.
- Kimi K3 has a larger context window (1M vs 131K tokens).
- Kimi K3 ranks higher for coding (94th vs 10th percentile).
| Attribute | gpt-oss-20b | Kimi K3 |
|---|---|---|
| Scores | ||
| Intelligence (ECI) | 138 | 158 |
| Coding | 10 | 94 |
| Math | 4 | 74 |
| Reasoning & Knowledge | 6 | 69 |
| Agentic & Tools | 6 | 66 |
| Specifications | ||
| Developer | OpenAI | Moonshot |
| Family | GPT | Kimi |
| Released | Aug 5, 2025 | Jul 16, 2026 |
| Parameters | 20.9B | 2.8T |
| Availability | Open weights (unrestricted) | Open weights (non-commercial) |
| Context window | 131K | 1M |
| Price — $/M input | $0.02 | $1.44 |
| Price — $/M output | $0.09 | $9.00 |
| Inputs | text | text, image, video |
| Outputs | text | text |
| Benchmarks | ||
| AIME 2024/2025 | 65% | 97% |
| GPQA Diamond | 61% | 93% |
| Humanity's Last Exam | 5% | 47% |
| LiveCodeBench | 65% | — |
| MMLU-Pro | 72% | — |
| SciCode | 39% | 60% |
| Terminal-Bench | 3% | — |
| WeirdML | 41% | 83% |
| τ²-bench | 50% | — |
| APEX | — | 51% |
| ARC-AGI | — | 95% |
| ARC-AGI-2 | — | 60% |
| SimpleBench | — | 61% |
| SimpleQA Verified | — | 51% |
| WebDev Arena | — | 1674 |
Use-case scores are 0–100 percentile composites across each area’s benchmarks, ranked against every model from the past year. Highlighted cells lead each row. Open a model for the full picture.
Frequently asked questions
Is gpt-oss-20b better than Kimi K3?
On Epoch AI's Capabilities Index, Kimi K3 scores higher (158) than gpt-oss-20b (138). The right pick depends on your task — compare their coding, math, and reasoning scores in the table above.
Which is cheaper, gpt-oss-20b or Kimi K3?
gpt-oss-20b is cheaper on input tokens at $0.02 per million, versus $1.44 (representative OpenRouter pricing).
Which has a larger context window, gpt-oss-20b or Kimi K3?
Kimi K3 supports up to 1M tokens, compared with 131K for the other.
Which is better for coding, gpt-oss-20b or Kimi K3?
Across coding benchmarks like SWE-bench Verified and Terminal-Bench, Kimi K3 ranks higher — 94th vs 10th percentile among the models tracked on Model Beat.
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Benchmarks & model data from Epoch AI (CC BY); pricing & specs from OpenRouter. ECI = Epoch Capabilities Index.