Claude Sonnet 4.6 vs GPT-OSS 20B
Sonnet strikes back. The price-performance sweet spot. Meanwhile, gpt-oss 20b: openai's open-weights return.
Side-by-side
Specs
| Dimension | Claude Sonnet 4.6 | GPT-OSS 20B |
|---|---|---|
| Provider | Anthropic | OpenAI |
| Released | 2025-12 | 2025-09 |
| Context window | ✓1M | 128K |
| Output max | ✓64K | 8K |
| Input /M | $3.00 | ✓$0.15 |
| Output /M | $15.00 | ✓$0.60 |
| Modalities | ✓text, image | text |
| Open weights | no | ✓yes |
Scorecard
Dimension-by-dimension
Claude Sonnet 4.6
GPT-OSS 20B
reasoning
9.0
7.0
coding
9.0
7.0
writing
9.0
7.0
speed
7.0
9.0
value
9.0
10.0
Verdict
Which wins, by use case
| Use case | Winner | Why |
|---|---|---|
| coding | Claude Sonnet 4.6 | a clear edge on our weighted coding score |
| writing | Claude Sonnet 4.6 | a clear edge on our weighted writing score |
| chat | GPT-OSS 20B | a coin flip on our weighted chat score |
| agents | Claude Sonnet 4.6 | a clear edge on our weighted agents score |
| summarization | GPT-OSS 20B | a clear edge on our weighted summarization score |
| translation | Claude Sonnet 4.6 | a coin flip on our weighted translation score |
| reasoning | Claude Sonnet 4.6 | a decisive lead on our weighted reasoning score |
| research | Claude Sonnet 4.6 | a clear edge on our weighted research score |
| vision and multimodal | Claude Sonnet 4.6 | a clear edge on our weighted vision score |
| Cheapest AI models for bulk workloads | GPT-OSS 20B | a clear edge on our weighted cheap-bulk score |
Bottom line
Our take
Pick Claude Sonnet 4.6 if you need: excellent value per token, strong code generation.
Pick GPT-OSS 20B if you need: single-gpu inference, open weights.
At a 500M-input / 150M-output monthly volume, Claude Sonnet 4.6 costs roughly $3750 vs GPT-OSS 20B at $165. Use our calculator to plug in your own numbers.
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