gpt-oss-20b vs Grok 4.1 Fast
Benchmarks, API pricing and specs, head to head. Data updated 2026-06-10.
OpenAI · Aug 2025
The small gpt-oss variant that runs on a 16GB consumer GPU or laptop — local reasoning for everyone, Apache 2.0 licensed.
xAI · Nov 2025
A 2M-token context window for $0.20 per million input tokens — the cheapest long-context frontier offering anywhere.
The verdict
These two models don't yet share verified results on the benchmarks we track, so judge them on specs, pricing and intended use. On price the gap is dramatic: gpt-oss-20b works out roughly 3.1x cheaper per blended million tokens. Grok 4.1 Fast also takes 2M of context versus 131K for gpt-oss-20b. And gpt-oss-20b is open-weights (Apache 2.0), so it can be self-hosted — a structural advantage if data control or vendor independence matters.
Specs & pricing
| gpt-oss-20b | Grok 4.1 Fast | |
|---|---|---|
| modhub Index | — | — |
| Input price / 1M | $0.05 | $0.2 |
| Output price / 1M | $0.2 | $0.5 |
| Context window | 131K | 2M |
| Max output | 131K | — |
| Open weights | yes (Apache 2.0) | no |
| Reasoning model | yes | yes |
| Multimodal input | text | text, image |
| Knowledge cutoff | Jun 2024 | Nov 2025 |
| Released | Aug 2025 | Nov 2025 |
| Example monthly cost* | $0.8 | $2.75 |
* 10M input + 1.5M output tokens per month at list prices, no caching. Green = better value on that row.
Frequently asked questions
- Which is better, gpt-oss-20b or Grok 4.1 Fast?
- These two models don't yet share verified results on the benchmarks we track, so judge them on specs, pricing and intended use. On price the gap is dramatic: gpt-oss-20b works out roughly 3.1x cheaper per blended million tokens. Grok 4.1 Fast also takes 2M of context versus 131K for gpt-oss-20b. And gpt-oss-20b is open-weights (Apache 2.0), so it can be self-hosted — a structural advantage if data control or vendor independence matters.
- Which is cheaper, gpt-oss-20b or Grok 4.1 Fast?
- gpt-oss-20b costs $0.05/$0.2 per million input/output tokens, while Grok 4.1 Fast costs $0.2/$0.5. For a typical workload of 10M input and 1.5M output tokens per month, that's $0.8 versus $2.75.
- Which model is better for coding, gpt-oss-20b or Grok 4.1 Fast?
- We don't yet track SWE-bench Verified results for both models; check their individual pages for coding-related scores.