Model Comparison

GPT-5.1 vs Grok-3Which is better in 2026?

GPT-5.1 significantly outperforms across most benchmarks. GPT-5.1 is 1.7x cheaper per token.

Verdict: GPT-5.1 vs Grok-3 — which is better?

GPT-5.1 (by OpenAI) and Grok-3 (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.

GPT-5.1 outperforms in 3 benchmarks (AIME 2025, GPQA, MMMU), while Grok-3 is better at 0 benchmarks. GPT-5.1 significantly outperforms across most benchmarks.

On price, GPT-5.1 is roughly 1.7x cheaper per token on a blended 3:1 input/output basis, which adds up quickly at production volume.

GPT-5.1 also accepts a larger context window (400,000 input tokens), making it the stronger choice for long documents and large codebases.

Choose GPT-5.1 if…

  • you want the strongest raw capability — it leads on 3 of 3 shared benchmarks
  • cost matters — it's about 1.7x cheaper per token
  • you process long inputs — it offers a 400,000 token context window
  • you want the most recent training data — it shipped Nov 2025

Choose Grok-3 if…

  • you want predictable pricing at $3.00/M input and $15.00/M output

Performance Benchmarks

Comparative analysis across standard metrics

3 benchmarks

GPT-5.1 outperforms in 3 benchmarks (AIME 2025, GPQA, MMMU), while Grok-3 is better at 0 benchmarks.

GPT-5.1 significantly outperforms across most benchmarks.

Thu Jul 23 2026 • llm-stats.com

Arena Performance

Human preference votes

Pricing Analysis

Price comparison per million tokens

GPT-5.1 costs less

For input processing, GPT-5.1 ($1.25/1M tokens) is 2.4x cheaper than Grok-3 ($3.00/1M tokens).

For output processing, GPT-5.1 ($10.00/1M tokens) is 1.5x cheaper than Grok-3 ($15.00/1M tokens).

In conclusion, Grok-3 is more expensive than GPT-5.1.*

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

Lowest available price from all providers
Thu Jul 23 2026 • llm-stats.com
OpenAI
GPT-5.1
Input tokens$1.25
Output tokens$10.00
Best providerOpenAI
xAI
Grok-3
Input tokens$3.00
Output tokens$15.00
Best providerxAI
Notice missing or incorrect data?Start an Issue→

Context Window

Maximum input and output token capacity

GPT-5.1 accepts 400,000 input tokens compared to Grok-3's 128,000 tokens. GPT-5.1 can generate longer responses up to 128,000 tokens, while Grok-3 is limited to 8,000 tokens.

OpenAI
GPT-5.1
Input400,000 tokens
Output128,000 tokens
xAI
Grok-3
Input128,000 tokens
Output8,000 tokens
Thu Jul 23 2026 • llm-stats.com

Input Capabilities

Supported data types and modalities

Both GPT-5.1 and Grok-3 support multimodal inputs.

They are both capable of processing various types of data, offering versatility in application.

GPT-5.1

Text
Images
Audio
Video

Grok-3

Text
Images
Audio
Video

License

Usage and distribution terms

Both models are licensed under proprietary licenses.

Both models have usage restrictions defined by their respective organizations.

GPT-5.1

Proprietary

Closed source

Grok-3

Proprietary

Closed source

Release Timeline

When each model was launched

GPT-5.1 was released on 2025-11-13, while Grok-3 was released on 2025-02-17.

GPT-5.1 is 9 months newer than Grok-3.

GPT-5.1

Nov 13, 2025

8 months ago

8mo newer
Grok-3

Feb 17, 2025

1.4 years ago

Knowledge Cutoff

When training data ends

GPT-5.1 has a knowledge cutoff of 2024-09-30, while Grok-3 has a cutoff of 2024-11-17.

Grok-3 has more recent training data (up to 2024-11-17), making it potentially better informed about events through that date compared to GPT-5.1 (2024-09-30).

GPT-5.1

Sep 2024

Grok-3

Nov 2024

2 mo newer

Provider Availability

GPT-5.1 is available from OpenAI. Grok-3 is available from xAI.

GPT-5.1

openai logo
OpenAI
Input Price:Input: $1.25/1MOutput Price:Output: $10.00/1M

Grok-3

xai logo
xAI
Input Price:Input: $3.00/1MOutput Price:Output: $15.00/1M
* Prices shown are per million tokens

Outputs Comparison

Notice missing or incorrect data?Start an Issue discussion→

Key Takeaways

OpenAI
Larger context window (400,000 tokens)
Less expensive input tokens
Less expensive output tokens
Higher AIME 2025 score (94.0% vs 93.3%)
Higher GPQA score (88.1% vs 84.6%)
Higher MMMU score (85.4% vs 78.0%)
xAI

No standout differentiators in the data we have for this pair.

OpenAIGPT-5.1
xAIGrok-3
Compare in Playground

Detailed Comparison

Interactive Arena

Judge for yourself.

Run your own prompts against GPT-5.1 and Grok-3 side-by-side, then vote on the output you prefer.

GPT-5.1
✓ Preferred
Grok-3
Open in Playground
AI Model Comparison Table
Feature
OpenAI
GPT-5.1
xAI
Grok-3

FAQ

Common questions about GPT-5.1 vs Grok-3.

Which is better, GPT-5.1 or Grok-3?

GPT-5.1 significantly outperforms across most benchmarks. GPT-5.1 is made by OpenAI and Grok-3 is made by xAI. The best choice depends on your use case — compare their benchmark scores, pricing, and capabilities above.

How does GPT-5.1 compare to Grok-3 in benchmarks?

GPT-5.1 scores Tau2 Telecom: 95.6%, AIME 2025: 94.0%, BrowseComp Long Context 128k: 90.0%, GPQA: 88.1%, MMMU: 85.4%. Grok-3 scores AIME 2024: 93.3%, AIME 2025: 93.3%, GPQA: 84.6%, LiveCodeBench: 79.4%, MMMU: 78.0%.

Is GPT-5.1 cheaper than Grok-3?

GPT-5.1 is 2.4x cheaper for input tokens. GPT-5.1 costs $1.25/M input and $10.00/M output via openai. Grok-3 costs $3.00/M input and $15.00/M output via xai.

What are the context window sizes for GPT-5.1 and Grok-3?

GPT-5.1 supports 400K tokens and Grok-3 supports 128K tokens. A larger context window lets you process longer documents, conversations, or codebases in a single request.

What are the main differences between GPT-5.1 and Grok-3?

Key differences include context window (400K vs 128K), input pricing ($1.25 vs $3.00/M). See the full comparison above for benchmark-by-benchmark results.

Who makes GPT-5.1 and Grok-3?

GPT-5.1 is developed by OpenAI and Grok-3 is developed by xAI.

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