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Gemini 3.1 Pro Preview vs GPT-5.5

Updated October 21, 2026. 118 benchmarks have a result for both. Coding is ranked on the Vibe Coding Index; every other board is shown as published.

Replace Gemini 3.1 Pro Preview Replace GPT-5.5
Gemini 3.1 Pro PreviewGoogle
Coding
35.3
Overall
29.7
Output $/M
$12.00
41
GPT-5.5OpenAI
Coding
67.8
Overall
38.4
Output $/M
$30.00
77
vs boards won of 118 shared

Decision reading

Pick GPT-5.5 for coding: it scores 67.8 on the Vibe Coding Index against 35.3 for Gemini 3.1 Pro Preview.

Pick Gemini 3.1 Pro Preview when output tokens cost 2.5x less, or when a solved task costs $0.99 against $1.65.

Model AGemini 3.1 Pro PreviewGoogle35.3/1001 independent benchmark$0.99 per solved taskModel BGPT-5.5OpenAI67.8/1002 independent benchmarks$1.65 per solved task
Shared results
118
Gemini 3.1 Pro Preview only
13
GPT-5.5 only
14
Like-for-like categories
8 of 9

Shared results can support a head-to-head reading. Results only one model has describe coverage, not superiority.

Which one for your work

Each card is decided by one number both models carry. Where only one has it, the card says so and makes no call.

At a glance

Coding index
Gemini 3.1 Pro Preview 35.3 from 1 benchmark, GPT-5.5 67.8 from 2 benchmarks.
Widest category
Math, 18.3 points apart on average over 6 shared benchmarks.
Widest single gap
FrontierMath, tier 4: Gemini 3.1 Pro Preview 26.8% against GPT-5.5 72.5%, 45.7 points apart on a 0 to 100 scale.
Output price
Gemini 3.1 Pro Preview $12.00 against GPT-5.5 $30.00 per million output tokens, 2.5x apart.
Context window
Gemini 3.1 Pro Preview takes 1.05M tokens, GPT-5.5 1.05M.

Benchmark by benchmark

First the score: boards each model leads, per category, where both have a result. Then every board, a category to a fold; bars are each result on a 0 to 100 scale, so compare the two in a row, not one row with another.

Boards won, where both have a result
CategoryGemini 3.1 Pro PreviewBarsGPT-5.5Ties
Coding218
Intelligence01
Agentic work415
Reasoning610
Math15
Knowledge75
Web design35
General1818
All shared boards4177
CodingLike-for-likeFour of these boards feed the Vibe Coding Index218
Coding benchmarks for Gemini 3.1 Pro Preview and GPT-5.5
BenchmarkGemini 3.1 Pro PreviewGPT-5.5Leader
LiveBench codingNot measured85.1%Only GPT-5.5 measured
LMArena WebDev14471513GPT-5.5
AA Coding Index68.874.9GPT-5.5
LiveCodeBench (Vals AI)88.5%85.3%Gemini 3.1 Pro Preview
SWE-bench Verified (Vals AI)78.8%82.6%GPT-5.5
Terminal-Bench 4 (Vals AI)2.5%Not measuredOnly Gemini 3.1 Pro Preview measured
Vibe Code Bench (Vals AI)32.0%69.8%GPT-5.5
Code migration (Vals AI)17.3%45.2%GPT-5.5
ProgramBench (Vals AI)0.0%0.5%GPT-5.5
IOI (Vals AI)51.8%Not measuredOnly Gemini 3.1 Pro Preview measured
Terminal-Bench 2.1 (Vals AI)70.8%76.4%GPT-5.5
Vibe Code Bench 1-100 (Vals AI)6.7%Not measuredOnly Gemini 3.1 Pro Preview measured
SkillsBench (Vals AI)Not measured62.5%Only GPT-5.5 measured
SciCode58.7%56.1%Gemini 3.1 Pro Preview
Terminal-Bench Hard (Artificial Analysis run)53.8%60.6%GPT-5.5
Terminal-Bench80.2%84.7%GPT-5.5
FrontierCodeNot measured43.0%Only GPT-5.5 measured
GSO-Bench22.6%40.2%GPT-5.5
WeirdML72.1%84.9%GPT-5.5
MirrorCode8.9%10.0%GPT-5.5
ALE-Bench1160.61943.0GPT-5.5
LMArena Text: coding14841494GPT-5.5
LMArena Text: software and IT14871493GPT-5.5
LMArena WebDev: React14381506GPT-5.5
LMArena WebDev: HTML14901543GPT-5.5
LMArena WebDev: from an image14811532GPT-5.5
Neither model has a result on the other 12 boards here
IntelligenceLike-for-likePublic boards, shown as published, kept out of the index01
Intelligence benchmarks for Gemini 3.1 Pro Preview and GPT-5.5
BenchmarkGemini 3.1 Pro PreviewGPT-5.5Leader
AA Intelligence Index29.738.4GPT-5.5
Epoch Capabilities IndexNot measured159.7Only GPT-5.5 measured
Agentic workLike-for-likePublic boards, shown as published, kept out of the index415
Agentic work benchmarks for Gemini 3.1 Pro Preview and GPT-5.5
BenchmarkGemini 3.1 Pro PreviewGPT-5.5Leader
AA Agentic Index8.236.4GPT-5.5
Design Arena: agents building web apps11251117Gemini 3.1 Pro Preview
Design Arena: agents building full-stack apps10681089GPT-5.5
Design Arena: agents building mobile apps10941143GPT-5.5
Design Arena: agents building Android apps10551169GPT-5.5
Design Arena: agents building Godot games12361173Gemini 3.1 Pro Preview
Design Arena: agents building games11141179GPT-5.5
Design Arena: HTML slides11531067Gemini 3.1 Pro Preview
Design Arena: PowerPoint slides10641108GPT-5.5
LiveBench researchNot measured61.6%Only GPT-5.5 measured
LiveBench browserNot measured48.0%Only GPT-5.5 measured
LiveBench long agenticNot measured44.6%Only GPT-5.5 measured
SREBench (Vals AI)0.0%3.8%GPT-5.5
Finance Agent (Vals AI)43.0%51.8%GPT-5.5
Tax Agent Bench (Vals AI)9.3%21.8%GPT-5.5
Legal Research Bench (Vals AI)20.7%40.4%GPT-5.5
Excel Modeling Benchmark (Vals AI)52.6%64.5%GPT-5.5
BioMysteryBench (Vals AI)60.0%Not measuredOnly Gemini 3.1 Pro Preview measured
Terminal-Bench-Science (Vals AI)1.4%Not measuredOnly Gemini 3.1 Pro Preview measured
Vals Science Index27.4%Not measuredOnly Gemini 3.1 Pro Preview measured
Time Horizon Index (Vals AI)Not measured8.3%Only GPT-5.5 measured
τ²-Bench Telecom95.6%93.9%Gemini 3.1 Pro Preview
APEX-Agents35.1%55.1%GPT-5.5
METR time horizons77.0%Not measuredOnly Gemini 3.1 Pro Preview measured
Remote Labor IndexNot measured6.3%Only GPT-5.5 measured
OSWorld 2.0Not measured13.0%Only GPT-5.5 measured
BALROG57.0%Not measuredOnly Gemini 3.1 Pro Preview measured
DeepResearch Bench47.8%54.0%GPT-5.5
PostTrainBench22.0%27.2%GPT-5.5
Vending-Bench 2$911$7,524GPT-5.5
Neither model has a result on the other 9 boards here
ReasoningLike-for-likePublic boards, shown as published, kept out of the index610
Reasoning benchmarks for Gemini 3.1 Pro Preview and GPT-5.5
BenchmarkGemini 3.1 Pro PreviewGPT-5.5Leader
GPQA Diamond95.5%93.2%Gemini 3.1 Pro Preview
LiveBench reasoningNot measured89.7%Only GPT-5.5 measured
MysteryMechanism (Vals AI)20.7%Not measuredOnly Gemini 3.1 Pro Preview measured
MMMU Pro (Vals AI)88.2%88.3%GPT-5.5
GPQA Diamond (Artificial Analysis run)94.1%93.5%Gemini 3.1 Pro Preview
Humanity's Last Exam (Artificial Analysis run)47.0%45.8%Gemini 3.1 Pro Preview
GPQA Diamond (Epoch AI run)94.4%90.7%Gemini 3.1 Pro Preview
ARC-AGI98.0%95.0%Gemini 3.1 Pro Preview
ARC-AGI-277.1%85.0%GPT-5.5
SimpleBench79.6%69.0%Gemini 3.1 Pro Preview
Chess puzzles51.0%63.0%GPT-5.5
Mystery game puzzles34.0%56.0%GPT-5.5
EBR-bench14.3%34.3%GPT-5.5
LMArena Text: hard prompts14851489GPT-5.5
LMArena Text: expert14831507GPT-5.5
LMArena Text: hard prompts in English14801483GPT-5.5
LMArena Vision: diagrams13111325GPT-5.5
LMArena Vision: homework13161332GPT-5.5
Neither model has a result on the other 3 boards here
MathLike-for-likePublic boards, shown as published, kept out of the index15
Math benchmarks for Gemini 3.1 Pro Preview and GPT-5.5
BenchmarkGemini 3.1 Pro PreviewGPT-5.5Leader
AIME98.1%Not measuredOnly Gemini 3.1 Pro Preview measured
OTIS Mock AIME95.6%84.4%Gemini 3.1 Pro Preview
FrontierMath, tiers 1 to 359.6%85.3%GPT-5.5
FrontierMath, tier 426.8%72.5%GPT-5.5
ProofBench26.0%50.0%GPT-5.5
LMArena Text: math14861487GPT-5.5
LMArena Text: mathematical work14781496GPT-5.5
Neither model has a result on the other 6 boards here
KnowledgeLike-for-likePublic boards, shown as published, kept out of the index75
Knowledge benchmarks for Gemini 3.1 Pro Preview and GPT-5.5
BenchmarkGemini 3.1 Pro PreviewGPT-5.5Leader
MMLU Pro91.0%88.1%Gemini 3.1 Pro Preview
LegalBench (Vals AI)87.4%86.5%Gemini 3.1 Pro Preview
CaseLaw (Vals AI)64.8%66.2%GPT-5.5
CorpFin (Vals AI)64.5%68.4%GPT-5.5
TaxEval (Vals AI)72.9%75.0%GPT-5.5
MortgageTax (Vals AI)69.4%68.8%Gemini 3.1 Pro Preview
MedQA (Vals AI)96.4%Not measuredOnly Gemini 3.1 Pro Preview measured
MedCode (Vals AI)59.1%49.1%Gemini 3.1 Pro Preview
SimpleQA Verified73.5%63.0%Gemini 3.1 Pro Preview
LMArena Text: science14971485Gemini 3.1 Pro Preview
LMArena Text: medicine and healthcare14861465Gemini 3.1 Pro Preview
LMArena Text: legal and government14871491GPT-5.5
LMArena Text: business and finance14591478GPT-5.5
Neither model has a result on the other 4 boards here
Web designLike-for-likePublic boards, shown as published, kept out of the index35
Web design benchmarks for Gemini 3.1 Pro Preview and GPT-5.5
BenchmarkGemini 3.1 Pro PreviewGPT-5.5Leader
Design Arena: websites12341256GPT-5.5
Design Arena: UI components12261260GPT-5.5
Design Arena: game dev12031294GPT-5.5
Design Arena: data viz12091265GPT-5.5
Design Arena: 3D12341198Gemini 3.1 Pro Preview
Design Arena: all code categories12311260GPT-5.5
Design Arena: SVG12851234Gemini 3.1 Pro Preview
Design Arena: ASCII art12701254Gemini 3.1 Pro Preview
LiveBench designNot measured70.3%Only GPT-5.5 measured
GeneralLike-for-likePublic boards, shown as published, kept out of the index1818
General benchmarks for Gemini 3.1 Pro Preview and GPT-5.5
BenchmarkGemini 3.1 Pro PreviewGPT-5.5Leader
LiveBench data analysisNot measured81.6%Only GPT-5.5 measured
Public Benefits Bench (Vals AI)53.8%60.9%GPT-5.5
SAGE (Vals AI)48.7%51.5%GPT-5.5
MedScribe (Vals AI)76.1%86.9%GPT-5.5
Vals Multimodal Index56.1%68.1%GPT-5.5
IFBench77.1%75.9%Gemini 3.1 Pro Preview
Long context reasoning (AA-LCR)82.0%84.3%GPT-5.5
DTBench97.1%96.0%Gemini 3.1 Pro Preview
LMCA53.8%54.3%GPT-5.5
CL-bench20.8%Not measuredOnly Gemini 3.1 Pro Preview measured
Surface Evolver BenchNot measured88.1%Only GPT-5.5 measured
Furniture assembly26.7%44.2%GPT-5.5
ExploitBench26.1%47.4%GPT-5.5
CL-bench Life16.9%22.2%GPT-5.5
LMArena Text14801471Gemini 3.1 Pro Preview
LMArena Text: instruction following14661478GPT-5.5
LMArena Text: creative writing14821455Gemini 3.1 Pro Preview
LMArena Vision12961297GPT-5.5
LMArena Text: English14781470Gemini 3.1 Pro Preview
LMArena Text: non-English14761467Gemini 3.1 Pro Preview
LMArena Text: Chinese15271534GPT-5.5
LMArena Text: German14901480Gemini 3.1 Pro Preview
LMArena Text: Japanese14911499GPT-5.5
LMArena Text: Korean14551460GPT-5.5
LMArena Text: French14871485Gemini 3.1 Pro Preview
LMArena Text: Spanish14811468Gemini 3.1 Pro Preview
LMArena Text: Russian14971473Gemini 3.1 Pro Preview
LMArena Text: Polish14981465Gemini 3.1 Pro Preview
LMArena Text: multi-turn14871476Gemini 3.1 Pro Preview
LMArena Text: longer queries14821484GPT-5.5
LMArena Text: writing and language14811466Gemini 3.1 Pro Preview
LMArena Text: entertainment and media14651449Gemini 3.1 Pro Preview
LMArena Vision: English12871292GPT-5.5
LMArena Vision: Chinese13641360Gemini 3.1 Pro Preview
LMArena Vision: reading text13041306GPT-5.5
LMArena Vision: humor13221293Gemini 3.1 Pro Preview
LMArena Vision: captioning1345Not measuredOnly Gemini 3.1 Pro Preview measured
LMArena Vision: recognizing things13301231Gemini 3.1 Pro Preview
LMArena Vision: creative writing13241301Gemini 3.1 Pro Preview
LMArena Document14441486GPT-5.5
Neither model has a result on the other 6 boards here
Image generationNot comparablePublic boards, shown as published, kept out of the index0 boards, none shared
Image generation benchmarks for Gemini 3.1 Pro Preview and GPT-5.5
BenchmarkGemini 3.1 Pro PreviewGPT-5.5Leader
Neither model has a result on 5 boards here

What each workload costs

Three fixed token mixes at each model's listed price, so per-token rates become a bill.

Chat turn

1K input + 500 output tokens

Gemini 3.1 Pro Preview$0.0080Fits in one request
GPT-5.5$0.020Fits in one request

Gemini 3.1 Pro Preview costs less

Repository review

50K input + 3K output tokens

Gemini 3.1 Pro Preview$0.136Fits in one request
GPT-5.5$0.340Fits in one request

Gemini 3.1 Pro Preview costs less

Agent loop

200K input + 10K output tokens

Gemini 3.1 Pro Preview$0.520Fits in one request
GPT-5.5$1.30Fits in one request

Gemini 3.1 Pro Preview costs less

Listed OpenRouter rates, without cache or batch discounts. A workload that does not fit a model's context window would need splitting.

Specification differences

The leading value in a row is marked; a row with a missing value names no leader. Our two rows are marked in red.

Specifications of Gemini 3.1 Pro Preview and GPT-5.5
SpecificationGoogle Gemini 3.1 Pro PreviewOpenAI GPT-5.5
MakerGoogleOpenAI
WeightsNo public weights listedNo public weights listed
ReleasedFebruary 19, 2026April 24, 2026
Context window1.05M1.05M
Input $/Mtok$2.00$5.00
Output $/Mtok$12.00$30.00
Coding index35.367.8
Independent measurements behind it12
Cost per solved task$0.99$1.65
SourceOpenRouter listingOpenRouter listing

Questions

Is Gemini 3.1 Pro Preview better than GPT-5.5 for coding?

Pick GPT-5.5 for coding: it scores 67.8 on the Vibe Coding Index against 35.3 for Gemini 3.1 Pro Preview. Pick Gemini 3.1 Pro Preview when output tokens cost 2.5x less, or when a solved task costs $0.99 against $1.65.

Which is cheaper, Gemini 3.1 Pro Preview or GPT-5.5?

Gemini 3.1 Pro Preview costs $2.00 per million input tokens and $12.00 per million output tokens; GPT-5.5 costs $5.00 and $30.00. Per solved SWE-bench Verified task, Gemini 3.1 Pro Preview costs $0.99 and GPT-5.5 $1.65.

Which has the bigger context window, Gemini 3.1 Pro Preview or GPT-5.5?

GPT-5.5, with 1.05M tokens against 1.05M.

How many benchmarks is the Gemini 3.1 Pro Preview vs GPT-5.5 comparison based on?

118 benchmarks have a result for both models as of October 21, 2026. Gemini 3.1 Pro Preview's coding index rests on 1 independent benchmark and GPT-5.5's on 2. Where only one model has a result, the page says so instead of naming a winner.

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