Model Comparison

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

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

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

Gemini 3.1 Pro (by Google) and GPT-5.1 Codex High (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 High is roughly 1.6x 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 High if…

  • cost matters — it's about 1.6x cheaper per token
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Performance Benchmarks

Comparative analysis across standard metrics

No common benchmarks found

Gemini 3.1 Pro and GPT-5.1 Codex Highdon'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 High costs less

For input processing, Gemini 3.1 Pro ($2.50/1M tokens) is 2.0x more expensive than GPT-5.1 Codex High ($1.25/1M tokens).

For output processing, Gemini 3.1 Pro ($15.00/1M tokens) is 1.5x more expensive than GPT-5.1 Codex High ($10.00/1M tokens).

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

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

Lowest available price from all providers
Sat Jun 13 2026 • llm-stats.com
Google
Gemini 3.1 Pro
Input tokens$2.50
Output tokens$15.00
Best providerGoogle
OpenAI
GPT-5.1 Codex High
Input tokens$1.25
Output tokens$10.00
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 High's 400,000 tokens. GPT-5.1 Codex High 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 High
Input400,000 tokens
Output128,000 tokens
Sat Jun 13 2026 • llm-stats.com

Input Capabilities

Supported data types and modalities

Both Gemini 3.1 Pro and GPT-5.1 Codex High 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 High

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 High

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 High was released on 2025-11-12.

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

Gemini 3.1 Pro

Feb 19, 2026

3 months ago

3mo newer
GPT-5.1 Codex High

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 High'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 High's cutoff date.

Gemini 3.1 Pro

Jan 2025

GPT-5.1 Codex High

—

Provider Availability

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

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

AI Model Comparison Table
Feature
Google
Gemini 3.1 Pro
OpenAI
GPT-5.1 Codex High

FAQ

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

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

Gemini 3.1 Pro (Google) and GPT-5.1 Codex High (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 High 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 High scores AIME 2025: 96.7%.

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

GPT-5.1 Codex High is 2.0x cheaper for input tokens. Gemini 3.1 Pro costs $2.50/M input and $15.00/M output via google. GPT-5.1 Codex High costs $1.25/M input and $10.00/M output via openai.

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

Gemini 3.1 Pro supports 1.0M tokens and GPT-5.1 Codex High 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 High?

Key differences include context window (1.0M vs 400K), input pricing ($2.50 vs $1.25/M). See the full comparison above for benchmark-by-benchmark results.

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

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

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