Model Comparison

Gemini 3.1 Pro vs GPT-5.1 Codex MiniWhich is better in 2026?

Comparing Gemini 3.1 Pro and GPT-5.1 Codex Mini across benchmarks, pricing, and capabilities.

Verdict: Gemini 3.1 Pro vs GPT-5.1 Codex Mini — which is better?

Gemini 3.1 Pro (by Google) and GPT-5.1 Codex Mini (by OpenAI) 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-5.1 Codex Mini is roughly 8.2x cheaper per token on a blended 3:1 input/output basis, which adds up quickly at production volume.

Gemini 3.1 Pro also accepts a larger context window (1,048,576 input tokens), making it the stronger choice for long documents and large codebases.

Choose Gemini 3.1 Pro if…

  • you process long inputs — it offers a 1,048,576 token context window
  • you want the most recent training data — it shipped Feb 2026

Choose GPT-5.1 Codex Mini if…

  • cost matters — it's about 8.2x cheaper per token

Performance Benchmarks

Comparative analysis across standard metrics

No common benchmarks found

Gemini 3.1 Pro and GPT-5.1 Codex Minidon'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-5.1 Codex Mini costs less

For input processing, Gemini 3.1 Pro ($2.50/1M tokens) is 10.0x more expensive than GPT-5.1 Codex Mini ($0.25/1M tokens).

For output processing, Gemini 3.1 Pro ($15.00/1M tokens) is 7.5x more expensive than GPT-5.1 Codex Mini ($2.00/1M tokens).

In conclusion, Gemini 3.1 Pro is more expensive than GPT-5.1 Codex Mini.*

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

Lowest available price from all providers
Fri Jun 26 2026 • llm-stats.com
Google
Gemini 3.1 Pro
Input tokens$2.50
Output tokens$15.00
Best providerGoogle
OpenAI
GPT-5.1 Codex Mini
Input tokens$0.25
Output tokens$2.00
Best providerOpenAI
Notice missing or incorrect data?Start an Issue→

Context Window

Maximum input and output token capacity

Gemini 3.1 Pro accepts 1,048,576 input tokens compared to GPT-5.1 Codex Mini's 400,000 tokens. GPT-5.1 Codex Mini can generate longer responses up to 128,000 tokens, while Gemini 3.1 Pro is limited to 65,536 tokens.

Google
Gemini 3.1 Pro
Input1,048,576 tokens
Output65,536 tokens
OpenAI
GPT-5.1 Codex Mini
Input400,000 tokens
Output128,000 tokens
Fri Jun 26 2026 • llm-stats.com

Input Capabilities

Supported data types and modalities

Both Gemini 3.1 Pro and GPT-5.1 Codex Mini support multimodal inputs.

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

Gemini 3.1 Pro

Text
Images
Audio
Video

GPT-5.1 Codex Mini

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.

Gemini 3.1 Pro

Proprietary

Closed source

GPT-5.1 Codex Mini

Proprietary

Closed source

Release Timeline

When each model was launched

Gemini 3.1 Pro was released on 2026-02-19, while GPT-5.1 Codex Mini was released on 2025-11-12.

Gemini 3.1 Pro is 3 months newer than GPT-5.1 Codex Mini.

Gemini 3.1 Pro

Feb 19, 2026

4 months ago

3mo newer
GPT-5.1 Codex Mini

Nov 12, 2025

7 months ago

Knowledge Cutoff

When training data ends

Gemini 3.1 Pro has a documented knowledge cutoff of 2025-01-31, while GPT-5.1 Codex Mini's cutoff date is not specified.

We can confirm Gemini 3.1 Pro's training data extends to 2025-01-31, but cannot make a direct comparison without GPT-5.1 Codex Mini's cutoff date.

Gemini 3.1 Pro

Jan 2025

GPT-5.1 Codex Mini

—

Provider Availability

Gemini 3.1 Pro is available from Google. GPT-5.1 Codex Mini is available from OpenAI.

Gemini 3.1 Pro

google logo
Google
Input Price:Input: $2.50/1MOutput Price:Output: $15.00/1M

GPT-5.1 Codex Mini

openai logo
OpenAI
Input Price:Input: $0.25/1MOutput Price:Output: $2.00/1M
* Prices shown are per million tokens

Outputs Comparison

Notice missing or incorrect data?Start an Issue discussion→

Key Takeaways

Google
Larger context window (1,048,576 tokens)
OpenAI
Less expensive input tokens
Less expensive output tokens

Detailed Comparison

Interactive Arena

Judge for yourself.

Run your own prompts against Gemini 3.1 Pro and GPT-5.1 Codex Mini side-by-side, then vote on the output you prefer.

Gemini 3.1 Pro
✓ Preferred
GPT-5.1 Codex Mini
Open in Playground
AI Model Comparison Table
Feature
Google
Gemini 3.1 Pro
OpenAI
GPT-5.1 Codex Mini

FAQ

Common questions about Gemini 3.1 Pro vs GPT-5.1 Codex Mini.

Which is better, Gemini 3.1 Pro or GPT-5.1 Codex Mini?

Gemini 3.1 Pro (Google) and GPT-5.1 Codex Mini (OpenAI) each have strengths in different areas. Compare their benchmark scores, pricing, context windows, and capabilities above to determine which fits your needs.

How does Gemini 3.1 Pro compare to GPT-5.1 Codex Mini in benchmarks?

Gemini 3.1 Pro scores t2-bench: 99.3%, LiveCodeBench Pro: 96.2%, GPQA: 94.3%, MMMLU: 92.6%, BrowseComp: 85.9%. GPT-5.1 Codex Mini scores AIME 2025: 42.1%.

Is Gemini 3.1 Pro cheaper than GPT-5.1 Codex Mini?

GPT-5.1 Codex Mini is 10.0x cheaper for input tokens. Gemini 3.1 Pro costs $2.50/M input and $15.00/M output via google. GPT-5.1 Codex Mini costs $0.25/M input and $2.00/M output via openai.

What are the context window sizes for Gemini 3.1 Pro and GPT-5.1 Codex Mini?

Gemini 3.1 Pro supports 1.0M tokens and GPT-5.1 Codex Mini supports 400K tokens. A larger context window lets you process longer documents, conversations, or codebases in a single request.

What are the main differences between Gemini 3.1 Pro and GPT-5.1 Codex Mini?

Key differences include context window (1.0M vs 400K), input pricing ($2.50 vs $0.25/M). See the full comparison above for benchmark-by-benchmark results.

Who makes Gemini 3.1 Pro and GPT-5.1 Codex Mini?

Gemini 3.1 Pro is developed by Google and GPT-5.1 Codex Mini is developed by OpenAI.

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