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Comparison · 2 models · Updated Oct 4, 2026

GPT-5.1 vs Gemini 3.1 Pro Preview

Gemini 3.1 Pro Preview comes out ahead, 68 to 60 on our weighted score, though GPT-5.1 is 24% cheaper per token.

  1. OpenAI

    GPT-5.1

    Released Nov 13, 2025

    60/100
    • ECI149.7
    • Price$1.25 / $10.00
    • Context400K
    Full specs Remove GPT-5.1
  2. Our pick

    Google

    Gemini 3.1 Pro Preview

    Released Feb 19, 2026

    68/100
    • ECI154.8
    • Price$2.00 / $12.00
    • Context1.05M
    Full specs Remove Gemini 3.1 Pro Preview

  3. Add a model

    Make it a three-way comparison.

01 — Verdict

Gemini 3.1 Pro Preview is our pick

Gemini 3.1 Pro Preview is the better all-round choice, scoring 68/100 against GPT-5.1 (60). It leads on capability, inputs & features and context window. GPT-5.1 wins on price. The score weighs capability 50%, price 25%, inputs & features 15%, context window 10%.

  • CapabilityGemini 3.1 Pro PreviewCapabilities Index (ECI): Gemini 3.1 Pro Preview 154.8 · GPT-5.1 149.7
  • Lowest priceGPT-5.1GPT-5.1 $3.44 · Gemini 3.1 Pro Preview $4.50 per 1M tokens (3:1 blend)
  • Longest contextGemini 3.1 Pro PreviewGemini 3.1 Pro Preview 1,048,576 · GPT-5.1 400,000 tokens
  • Widest inputsGemini 3.1 Pro PreviewGPT-5.1: Text, Images · Gemini 3.1 Pro Preview: Text, Images, PDFs, Audio, Video
  • Self-hostingNo open weightsBoth are available only through APIs
How the score is built
MeasureWeightGPT-5.1Gemini 3.1 Pro Preview
CapabilityCapabilities Index (ECI)50%7884
Price25%2419
Inputs & features15%70100
Context window10%4461
Overall100%60/10068/100
02 — Side by side

Every spec in one table

Highlighted cells lead their row. Dashes mean the data is not published.

GPT-5.1 vs Gemini 3.1 Pro Preview specifications side by side
SpecificationGPT-5.1OpenAIGemini 3.1 Pro PreviewGoogle
Capability
Capabilities Index (ECI)149.7154.8 (best)
ECI rank#52 of 148#31 of 148 (best)
GPQA DiamondGraduate-level science questions87.6%94.4% (best)
FrontierMath Tiers 1–3Research-level mathematics—59.7%
OTIS Mock AIME 2024–2025Competition mathematics88.6%95.6% (best)
SWE-bench VerifiedFixing real GitHub issues68.0%75.6% (best)
SimpleQA VerifiedShort factual questions48.0%73.5% (best)
Price per million tokens
Input$1.25 (best)$2.00
Output$10.00 (best)$12.00
Cached input$0.125 (best)$0.20
Blended (3:1)$3.44 (best)$4.50
Long-context rateSame rateOver 200K: $4.00 / $18.00
Price sourceOfficial OpenAI APIOfficial Google API
Limits
Context window400,000 tokens1,048,576 tokens (best)
Max output128,000 tokens (best)65,536 tokens
Inputs and features
TextYesYes
ImagesYesYes
PDFsNoYes
AudioNoYes
VideoNoYes
ReasoningYeslow · medium · highYeslow · medium · high
Tool callingYesYes
Structured outputYesYes
Availability
WeightsProprietaryProprietary
API model IDgpt-5.1gemini-3.1-pro-preview
API providers2126 (best)
ReleasedNov 13, 2025Feb 19, 2026
Knowledge cutoffSep 30, 2024Jan 2025
03 — Cost

What would a month cost?

Enter your expected volume in millions of tokens. List prices only; caching and batch discounts would lower these.

  • GPT-5.1$32.50
  • Gemini 3.1 Pro Preview$44.00
04 — Questions

Which should you choose?

Which is better: GPT-5.1 or Gemini 3.1 Pro Preview?

Gemini 3.1 Pro Preview is the better all-round choice, scoring 68/100 against GPT-5.1 (60). It leads on capability, inputs & features and context window. GPT-5.1 wins on price. The score weighs capability 50%, price 25%, inputs & features 15%, context window 10%.

Which is cheaper, GPT-5.1 or Gemini 3.1 Pro Preview?

GPT-5.1 is cheaper at $1.25 input / $10.00 output per million tokens (official OpenAI API price). Gemini 3.1 Pro Preview costs $2.00 input / $12.00 output per million tokens (official Google API price). At a typical mix of three input tokens to one output token, that is $3.44 per million tokens for GPT-5.1 versus $4.50 for Gemini 3.1 Pro Preview (1.3× as much).

Which scores higher on benchmarks?

Gemini 3.1 Pro Preview scores higher on the Capabilities Index (ECI): Gemini 3.1 Pro Preview 154.8 (#31 of 148) and GPT-5.1 149.7 (#52 of 148). Their confidence ranges do not overlap (152.6–157.3 vs 148.3–151.1), so the gap is a real one. On individual benchmarks: GPQA Diamond — Gemini 3.1 Pro Preview 94.4%, GPT-5.1 87.6%; OTIS Mock AIME 2024–2025 — Gemini 3.1 Pro Preview 95.6%, GPT-5.1 88.6%; SWE-bench Verified — Gemini 3.1 Pro Preview 75.6%, GPT-5.1 68.0%; SimpleQA Verified — Gemini 3.1 Pro Preview 73.5%, GPT-5.1 48.0%.

Which is better for coding?

Gemini 3.1 Pro Preview resolves more real GitHub issues on SWE-bench Verified: Gemini 3.1 Pro Preview 75.6% and GPT-5.1 68.0%. Both support tool calling for agent workflows.

Which has the bigger context window?

Gemini 3.1 Pro Preview has the largest context window at 1,048,576 tokens, against 400,000 for GPT-5.1. Maximum output per response: GPT-5.1 up to 128,000, Gemini 3.1 Pro Preview up to 65,536 tokens.

Which can read images, PDFs, audio or video?

GPT-5.1 accepts text and images; Gemini 3.1 Pro Preview accepts text, images, PDFs, audio and video. Gemini 3.1 Pro Preview handles the widest range of inputs.

Are any of these open source?

No. GPT-5.1 and Gemini 3.1 Pro Preview are proprietary and only available through APIs and apps.

Which is newer?

Gemini 3.1 Pro Preview is the newest, released Feb 19, 2026. GPT-5.1 came out Nov 13, 2025. Knowledge cutoff: GPT-5.1 Sep 30, 2024, Gemini 3.1 Pro Preview Jan 2025.

How do you decide the winner?

Each model gets a 0–100 score on capability (50%, independent benchmark results); price (25%, blended price per million tokens (3 input : 1 output), log scale); inputs & features (15%, image, PDF, audio and video input, tool calling, structured output and reasoning); context window (10%, maximum tokens per request, log scale). Dimensions missing for any model are dropped and the remaining weights rescaled, so every model is judged on the same evidence. Specs and prices come from public model listings and the labs’ own API pages; capability scores come from independent benchmark runs. Data updated Oct 4, 2026.

05 — Keep comparing

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