Model Comparison

GPT OSS 20B vs Grok Code Fast 1Which is better in 2026?

Comparing GPT OSS 20B and Grok Code Fast 1 across benchmarks, pricing, and capabilities.

Verdict: GPT OSS 20B vs Grok Code Fast 1 — which is better?

GPT OSS 20B (by OpenAI) and Grok Code Fast 1 (by xAI) are two of the AI models people compare most. Here is how they stack up on benchmarks, price and capabilities, and which one to pick in 2026.

On price, GPT OSS 20B is roughly 6.0x cheaper per token on a blended 3:1 input/output basis, which adds up quickly at production volume.

Grok Code Fast 1 also accepts a larger context window (256,000 input tokens), making it the stronger choice for long documents and large codebases.

Choose GPT OSS 20B if…

  • cost matters — it's about 6.0x cheaper per token
  • you need open weights you can self-host or fine-tune

Choose Grok Code Fast 1 if…

  • you process long inputs — it offers a 256,000 token context window
  • you want the most recent training data — it shipped Aug 2025

Performance Benchmarks

Comparative analysis across standard metrics

No common benchmarks found

GPT OSS 20B and Grok Code Fast 1don't have any common benchmark datasets to compare. They may have been evaluated on different testing suites.

Arena Performance

Human preference votes

Pricing Analysis

Price comparison per million tokens

GPT OSS 20B costs less

For input processing, GPT OSS 20B ($0.05/1M tokens) is 4.0x cheaper than Grok Code Fast 1 ($0.20/1M tokens).

For output processing, GPT OSS 20B ($0.20/1M tokens) is 7.5x cheaper than Grok Code Fast 1 ($1.50/1M tokens).

In conclusion, Grok Code Fast 1 is more expensive than GPT OSS 20B.*

* Using a 3:1 ratio of input to output tokens

Lowest available price from all providers
Sat Jun 27 2026 • llm-stats.com
OpenAI
GPT OSS 20B
Input tokens$0.05
Output tokens$0.20
Best providerNovita
xAI
Grok Code Fast 1
Input tokens$0.20
Output tokens$1.50
Best providerxAI
Notice missing or incorrect data?Start an Issue→

Context Window

Maximum input and output token capacity

Grok Code Fast 1 accepts 256,000 input tokens compared to GPT OSS 20B's 131,072 tokens. GPT OSS 20B can generate longer responses up to 32,768 tokens, while Grok Code Fast 1 is limited to 10,000 tokens.

OpenAI
GPT OSS 20B
Input131,072 tokens
Output32,768 tokens
xAI
Grok Code Fast 1
Input256,000 tokens
Output10,000 tokens
Sat Jun 27 2026 • llm-stats.com

License

Usage and distribution terms

GPT OSS 20B is licensed under Apache 2.0, while Grok Code Fast 1 uses a proprietary license.

License differences may affect how you can use these models in commercial or open-source projects.

GPT OSS 20B

Apache 2.0

Open weights

Grok Code Fast 1

Proprietary

Closed source

Release Timeline

When each model was launched

GPT OSS 20B was released on 2025-08-05, while Grok Code Fast 1 was released on 2025-08-28.

Grok Code Fast 1 is 1 month newer than GPT OSS 20B.

GPT OSS 20B

Aug 5, 2025

10 months ago

Grok Code Fast 1

Aug 28, 2025

10 months ago

3w newer

Knowledge Cutoff

When training data ends

Neither model specifies a knowledge cutoff date.

Unable to compare the recency of their training data.

No cutoff dates available

Provider Availability

GPT OSS 20B is available from Novita, Fireworks, Groq, OpenAI. Grok Code Fast 1 is available from xAI.

GPT OSS 20B

novita logo
Novita
Input Price:Input: $0.05/1MOutput Price:Output: $0.20/1M
fireworks logo
Fireworks
Input Price:Input: $0.10/1MOutput Price:Output: $0.50/1M
groq logo
Groq
Input Price:Input: $0.10/1MOutput Price:Output: $0.50/1M
openai logo
OpenAI
Input Price:Input: $0.10/1MOutput Price:Output: $0.50/1M

Grok Code Fast 1

xai logo
xAI
Input Price:Input: $0.20/1MOutput Price:Output: $1.50/1M
* Prices shown are per million tokens

Outputs Comparison

Notice missing or incorrect data?Start an Issue discussion→

Key Takeaways

OpenAI
Less expensive input tokens
Less expensive output tokens
Has open weights
xAI
Larger context window (256,000 tokens)

Detailed Comparison

Interactive Arena

Judge for yourself.

Run your own prompts against GPT OSS 20B and Grok Code Fast 1 side-by-side, then vote on the output you prefer.

GPT OSS 20B
✓ Preferred
Grok Code Fast 1
Open in Playground
AI Model Comparison Table
Feature
OpenAI
GPT OSS 20B
xAI
Grok Code Fast 1

FAQ

Common questions about GPT OSS 20B vs Grok Code Fast 1.

Which is better, GPT OSS 20B or Grok Code Fast 1?

GPT OSS 20B (OpenAI) and Grok Code Fast 1 (xAI) each have strengths in different areas. Compare their benchmark scores, pricing, context windows, and capabilities above to determine which fits your needs.

How does GPT OSS 20B compare to Grok Code Fast 1 in benchmarks?

GPT OSS 20B scores MMLU: 85.3%, CodeForces: 74.3%, GPQA: 71.5%, TAU-bench Retail: 54.8%, HealthBench: 42.5%. Grok Code Fast 1 scores SWE-Bench Verified: 70.8%.

Is GPT OSS 20B cheaper than Grok Code Fast 1?

GPT OSS 20B is 4.0x cheaper for input tokens. GPT OSS 20B costs $0.05/M input and $0.20/M output via novita. Grok Code Fast 1 costs $0.20/M input and $1.50/M output via xai.

What are the context window sizes for GPT OSS 20B and Grok Code Fast 1?

GPT OSS 20B supports 131K tokens and Grok Code Fast 1 supports 256K tokens. A larger context window lets you process longer documents, conversations, or codebases in a single request.

What are the main differences between GPT OSS 20B and Grok Code Fast 1?

Key differences include context window (131K vs 256K), input pricing ($0.05 vs $0.20/M), licensing (Apache 2.0 vs Proprietary). See the full comparison above for benchmark-by-benchmark results.

Who makes GPT OSS 20B and Grok Code Fast 1?

GPT OSS 20B is developed by OpenAI and Grok Code Fast 1 is developed by xAI.

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