Model Comparison

Gemini 3.1 Pro vs GPT-5.5 InstantWhich is better in 2026?

Gemini 3.1 Pro significantly outperforms across most benchmarks. Gemini 3.1 Pro is 2.0x cheaper per token.

Verdict: Gemini 3.1 Pro vs GPT-5.5 Instant — which is better?

Gemini 3.1 Pro (by Google) and GPT-5.5 Instant (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.

Gemini 3.1 Pro outperforms in 2 benchmarks (GPQA, MMMU-Pro), while GPT-5.5 Instant is better at 0 benchmarks. Gemini 3.1 Pro significantly outperforms across most benchmarks.

On price, Gemini 3.1 Pro is roughly 2.0x 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 want the strongest raw capability — it leads on 2 of 2 shared benchmarks
  • cost matters — it's about 2.0x cheaper per token
  • you process long inputs — it offers a 1,048,576 token context window

Choose GPT-5.5 Instant if…

  • you want the most recent training data — it shipped May 2026
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Performance Benchmarks

Comparative analysis across standard metrics

2 benchmarks

Gemini 3.1 Pro outperforms in 2 benchmarks (GPQA, MMMU-Pro), while GPT-5.5 Instant is better at 0 benchmarks.

Gemini 3.1 Pro significantly outperforms across most benchmarks.

Sun Jun 21 2026 • llm-stats.com

Arena Performance

Human preference votes

Pricing Analysis

Price comparison per million tokens

Gemini 3.1 Pro costs less

For input processing, Gemini 3.1 Pro ($2.50/1M tokens) is 2.0x cheaper than GPT-5.5 Instant ($5.00/1M tokens).

For output processing, Gemini 3.1 Pro ($15.00/1M tokens) is 2.0x cheaper than GPT-5.5 Instant ($30.00/1M tokens).

In conclusion, GPT-5.5 Instant is more expensive than Gemini 3.1 Pro.*

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

Lowest available price from all providers
Sun Jun 21 2026 • llm-stats.com
Google
Gemini 3.1 Pro
Input tokens$2.50
Output tokens$15.00
Best providerGoogle
OpenAI
GPT-5.5 Instant
Input tokens$5.00
Output tokens$30.00
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-5.5 Instant's 400,000 tokens. GPT-5.5 Instant 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-5.5 Instant
Input400,000 tokens
Output128,000 tokens
Sun Jun 21 2026 • llm-stats.com

Input Capabilities

Supported data types and modalities

Both Gemini 3.1 Pro and GPT-5.5 Instant 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-5.5 Instant

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-5.5 Instant

Proprietary

Closed source

Release Timeline

When each model was launched

Gemini 3.1 Pro was released on 2026-02-19, while GPT-5.5 Instant was released on 2026-05-05.

GPT-5.5 Instant is 3 months newer than Gemini 3.1 Pro.

Gemini 3.1 Pro

Feb 19, 2026

4 months ago

GPT-5.5 Instant

May 5, 2026

1 months ago

2mo newer

Knowledge Cutoff

When training data ends

Gemini 3.1 Pro has a knowledge cutoff of 2025-01-31, while GPT-5.5 Instant has a cutoff of 2025-08-31.

GPT-5.5 Instant has more recent training data (up to 2025-08-31), making it potentially better informed about events through that date compared to Gemini 3.1 Pro (2025-01-31).

Gemini 3.1 Pro

Jan 2025

GPT-5.5 Instant

Aug 2025

7 mo newer

Provider Availability

Gemini 3.1 Pro is available from Google. GPT-5.5 Instant is available from OpenAI.

Gemini 3.1 Pro

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

GPT-5.5 Instant

openai logo
OpenAI
Input Price:Input: $5.00/1MOutput Price:Output: $30.00/1M
* 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)
Less expensive input tokens
Less expensive output tokens
Higher GPQA score (94.3% vs 85.6%)
Higher MMMU-Pro score (80.5% vs 76.0%)
OpenAI

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

Detailed Comparison

AI Model Comparison Table
Feature
Google
Gemini 3.1 Pro
OpenAI
GPT-5.5 Instant

FAQ

Common questions about Gemini 3.1 Pro vs GPT-5.5 Instant.

Which is better, Gemini 3.1 Pro or GPT-5.5 Instant?

Gemini 3.1 Pro significantly outperforms across most benchmarks. Gemini 3.1 Pro is made by Google and GPT-5.5 Instant is made by OpenAI. The best choice depends on your use case — compare their benchmark scores, pricing, and capabilities above.

How does Gemini 3.1 Pro compare to GPT-5.5 Instant 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-5.5 Instant scores HealthBench Consensus: 94.7%, OmniDocBench 1.5: 87.5%, GPQA: 85.6%, CharXiv-R: 81.6%, AIME 2025: 81.2%.

Is Gemini 3.1 Pro cheaper than GPT-5.5 Instant?

Gemini 3.1 Pro is 2.0x cheaper for input tokens. Gemini 3.1 Pro costs $2.50/M input and $15.00/M output via google. GPT-5.5 Instant costs $5.00/M input and $30.00/M output via openai.

What are the context window sizes for Gemini 3.1 Pro and GPT-5.5 Instant?

Gemini 3.1 Pro supports 1.0M tokens and GPT-5.5 Instant 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-5.5 Instant?

Key differences include context window (1.0M vs 400K), input pricing ($2.50 vs $5.00/M). See the full comparison above for benchmark-by-benchmark results.

Who makes Gemini 3.1 Pro and GPT-5.5 Instant?

Gemini 3.1 Pro is developed by Google and GPT-5.5 Instant is developed by OpenAI.

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