Gemini 3 Flash Preview vs GPT-5.1
Updated October 21, 2026. 49 benchmarks have a result for both. Coding is ranked on the Vibe Coding Index; every other board is shown as published.
Decision reading
Pick Gemini 3 Flash Preview for coding: it scores 75.8 on the Vibe Coding Index against 53.3 for GPT-5.1, though on 1 benchmark against 2.
Pick GPT-5.1 when what matters is LiveCodeBench (Vals AI) or Vibe Code Bench (Vals AI), where it leads.
- Shared results
- 49
- Gemini 3 Flash Preview only
- 20
- GPT-5.1 only
- 51
- 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.
Coding
Vibe Coding Index, four public coding benchmarks
Gemini 3 Flash Preview
Gemini 3 Flash Preview scores 75.8 against 53.3.
1 and 2 benchmarks behind the scores
Intelligence
AA Intelligence Index
Gemini 3 Flash Preview
Gemini 3 Flash Preview leads, 26.3 against 24.7.
Same board, both measured
Reasoning
GPQA Diamond
Gemini 3 Flash Preview
Gemini 3 Flash Preview leads, 87.9% against 86.6%.
Same board, both measured
Math
AIME
Gemini 3 Flash Preview
Gemini 3 Flash Preview leads, 95.6% against 93.3%.
Same board, both measured
Knowledge
MMLU Pro
Gemini 3 Flash Preview
Gemini 3 Flash Preview leads, 88.6% against 86.4%.
Same board, both measured
Web design
Design Arena: websites
Gemini 3 Flash Preview
Gemini 3 Flash Preview leads, 1196 against 1187.
Same board, both measured
Long documents
Listed context window
Gemini 3 Flash Preview
Gemini 3 Flash Preview takes 1.05M tokens against 400K.
Listed by OpenRouter
Everyday cost
1K input + 500 output tokens
Gemini 3 Flash Preview
Gemini 3 Flash Preview $0.0020, GPT-5.1 $0.0063 per turn.
List prices
Cost per solved task
One SWE-bench Verified task, solved
Gemini 3 Flash Preview
Gemini 3 Flash Preview $0.37, GPT-5.1 $1.02.
Published attempt cost and pass rate
At a glance
- Coding index
- Gemini 3 Flash Preview 75.8 from 1 benchmark, GPT-5.1 53.3 from 2 benchmarks.
- Widest category
- Agentic work, 7.3 points apart on average over 3 shared benchmarks.
- Widest single gap
- SimpleQA Verified: Gemini 3 Flash Preview 66.8% against GPT-5.1 48.0%, 18.8 points apart on a 0 to 100 scale.
- Output price
- Gemini 3 Flash Preview $3.00 against GPT-5.1 $10.00 per million output tokens, 3.3x apart.
- Context window
- Gemini 3 Flash Preview takes 1.05M tokens, GPT-5.1 400K.
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.
| Category | Gemini 3 Flash Preview | Bars | GPT-5.1 | Ties |
|---|---|---|---|---|
| Coding | 5 | 4 | ||
| Intelligence | 1 | 0 | ||
| Agentic work | 2 | 1 | ||
| Reasoning | 10 | 1 | ||
| Math | 5 | 0 | ||
| Knowledge | 7 | 3 | ||
| Web design | 3 | 1 | ||
| General | 2 | 4 | ||
| All shared boards | 35 | 14 |
CodingLike-for-likeFour of these boards feed the Vibe Coding Index54
| Benchmark | Gemini 3 Flash Preview | GPT-5.1 | Leader |
|---|---|---|---|
| SWE-bench Verified | 75.8% | 66.0% | Gemini 3 Flash Preview |
| LMArena WebDev | Not measured | 1396 | Only GPT-5.1 measured |
| AA Coding Index | Not measured | 49.4 | Only GPT-5.1 measured |
| LiveCodeBench (Vals AI) | 85.6% | 86.5% | GPT-5.1 |
| SWE-bench Verified (Vals AI) | 75.0% | 69.8% | Gemini 3 Flash Preview |
| Vibe Code Bench (Vals AI) | 20.2% | 24.6% | GPT-5.1 |
| Code migration (Vals AI) | 6.4% | Not measured | Only Gemini 3 Flash Preview measured |
| ProgramBench (Vals AI) | 0.0% | Not measured | Only Gemini 3 Flash Preview measured |
| Terminal-Bench 2.1 (Vals AI) | 53.9% | Not measured | Only Gemini 3 Flash Preview measured |
| LiveCodeBench (Artificial Analysis run) | 90.8% | 86.8% | Gemini 3 Flash Preview |
| Terminal-Bench Hard (Artificial Analysis run) | 38.6% | 45.5% | GPT-5.1 |
| Terminal-Bench | 64.3% | 47.6% | Gemini 3 Flash Preview |
| GSO-Bench | 9.8% | 13.7% | GPT-5.1 |
| WeirdML | 61.6% | 60.8% | Gemini 3 Flash Preview |
| ALE-Bench | 1367.2 | Not measured | Only Gemini 3 Flash Preview measured |
| LMArena Text: coding | Not measured | 1453 | Only GPT-5.1 measured |
| LMArena Text: software and IT | Not measured | 1454 | Only GPT-5.1 measured |
| LMArena WebDev: React | Not measured | 1307 | Only GPT-5.1 measured |
| LMArena WebDev: HTML | Not measured | 1405 | Only GPT-5.1 measured |
| LMArena WebDev: from an image | Not measured | 1421 | Only GPT-5.1 measured |
| Neither model has a result on the other 18 boards here | |||
IntelligenceLike-for-likePublic boards, shown as published, kept out of the index10
| Benchmark | Gemini 3 Flash Preview | GPT-5.1 | Leader |
|---|---|---|---|
| AA Intelligence Index | 26.3 | 24.7 | Gemini 3 Flash Preview |
| Epoch Capabilities Index | Not measured | 149.8 | Only GPT-5.1 measured |
Agentic workLike-for-likePublic boards, shown as published, kept out of the index21
| Benchmark | Gemini 3 Flash Preview | GPT-5.1 | Leader |
|---|---|---|---|
| Design Arena: agents building web apps | 1111 | Not measured | Only Gemini 3 Flash Preview measured |
| Design Arena: agents building full-stack apps | 1063 | Not measured | Only Gemini 3 Flash Preview measured |
| Design Arena: agents building mobile apps | 1090 | Not measured | Only Gemini 3 Flash Preview measured |
| Design Arena: agents building Android apps | 1056 | Not measured | Only Gemini 3 Flash Preview measured |
| Design Arena: agents building Godot games | 1161 | Not measured | Only Gemini 3 Flash Preview measured |
| Design Arena: PowerPoint slides | 1036 | Not measured | Only Gemini 3 Flash Preview measured |
| Finance Agent (Vals AI) | 42.5% | Not measured | Only Gemini 3 Flash Preview measured |
| Tax Agent Bench (Vals AI) | 11.8% | Not measured | Only Gemini 3 Flash Preview measured |
| Legal Research Bench (Vals AI) | 18.3% | Not measured | Only Gemini 3 Flash Preview measured |
| Excel Modeling Benchmark (Vals AI) | 26.0% | Not measured | Only Gemini 3 Flash Preview measured |
| τ²-Bench Telecom | 80.4% | 81.9% | GPT-5.1 |
| BALROG | 48.1% | Not measured | Only Gemini 3 Flash Preview measured |
| DeepResearch Bench | 49.8% | 42.8% | Gemini 3 Flash Preview |
| Vending-Bench 2 | $3,635 | $1,473 | Gemini 3 Flash Preview |
| Neither model has a result on the other 25 boards here | |||
ReasoningLike-for-likePublic boards, shown as published, kept out of the index101
| Benchmark | Gemini 3 Flash Preview | GPT-5.1 | Leader |
|---|---|---|---|
| GPQA Diamond | 87.9% | 86.6% | Gemini 3 Flash Preview |
| MMMU Pro (Vals AI) | 87.6% | 83.2% | Gemini 3 Flash Preview |
| GPQA Diamond (Artificial Analysis run) | 89.8% | 87.3% | Gemini 3 Flash Preview |
| Humanity's Last Exam (Artificial Analysis run) | 36.6% | 28.5% | Gemini 3 Flash Preview |
| GPQA Diamond (Epoch AI run) | 89.4% | 87.6% | Gemini 3 Flash Preview |
| ARC-AGI | 84.7% | 72.8% | Gemini 3 Flash Preview |
| ARC-AGI-2 | 33.6% | 17.6% | Gemini 3 Flash Preview |
| SimpleBench | 61.1% | 53.2% | Gemini 3 Flash Preview |
| Chess puzzles | 39.0% | 42.0% | GPT-5.1 |
| Mystery game puzzles | 26.0% | 19.0% | Gemini 3 Flash Preview |
| VPCT | 72.6% | 58.7% | Gemini 3 Flash Preview |
| LMArena Text: hard prompts | Not measured | 1457 | Only GPT-5.1 measured |
| LMArena Text: expert | Not measured | 1470 | Only GPT-5.1 measured |
| LMArena Text: hard prompts in English | Not measured | 1462 | Only GPT-5.1 measured |
| LMArena Vision: diagrams | Not measured | 1264 | Only GPT-5.1 measured |
| LMArena Vision: homework | Not measured | 1272 | Only GPT-5.1 measured |
| Neither model has a result on the other 5 boards here | |||
MathLike-for-likePublic boards, shown as published, kept out of the index50
| Benchmark | Gemini 3 Flash Preview | GPT-5.1 | Leader |
|---|---|---|---|
| AIME | 95.6% | 93.3% | Gemini 3 Flash Preview |
| MGSM (Vals AI) | 93.3% | 93.0% | Gemini 3 Flash Preview |
| AA Math Index | 97.0 | 94.0 | Gemini 3 Flash Preview |
| AIME 2025 (Artificial Analysis run) | 97.0% | 94.0% | Gemini 3 Flash Preview |
| OTIS Mock AIME | 95.6% | 88.6% | Gemini 3 Flash Preview |
| FrontierMath, tiers 1 to 3 | 51.2% | Not measured | Only Gemini 3 Flash Preview measured |
| FrontierMath, tier 4 | 17.1% | Not measured | Only Gemini 3 Flash Preview measured |
| ProofBench | 15.0% | Not measured | Only Gemini 3 Flash Preview measured |
| LMArena Text: math | Not measured | 1446 | Only GPT-5.1 measured |
| LMArena Text: mathematical work | Not measured | 1449 | Only GPT-5.1 measured |
| Neither model has a result on the other 3 boards here | |||
KnowledgeLike-for-likePublic boards, shown as published, kept out of the index73
| Benchmark | Gemini 3 Flash Preview | GPT-5.1 | Leader |
|---|---|---|---|
| MMLU Pro | 88.6% | 86.4% | Gemini 3 Flash Preview |
| LegalBench (Vals AI) | 86.9% | 85.7% | Gemini 3 Flash Preview |
| CaseLaw (Vals AI) | 55.8% | 73.4% | GPT-5.1 |
| CorpFin (Vals AI) | 66.4% | 63.8% | Gemini 3 Flash Preview |
| TaxEval (Vals AI) | 73.9% | 74.9% | GPT-5.1 |
| MortgageTax (Vals AI) | 68.7% | 61.4% | Gemini 3 Flash Preview |
| MedQA (Vals AI) | 95.8% | 96.4% | GPT-5.1 |
| MedCode (Vals AI) | 55.9% | 52.7% | Gemini 3 Flash Preview |
| MMLU Pro (Artificial Analysis run) | 89.0% | 87.0% | Gemini 3 Flash Preview |
| SimpleQA Verified | 66.8% | 48.0% | Gemini 3 Flash Preview |
| GeoBench | 88.0% | Not measured | Only Gemini 3 Flash Preview measured |
| LMArena Text: science | Not measured | 1459 | Only GPT-5.1 measured |
| LMArena Text: medicine and healthcare | Not measured | 1456 | Only GPT-5.1 measured |
| LMArena Text: legal and government | Not measured | 1459 | Only GPT-5.1 measured |
| LMArena Text: business and finance | Not measured | 1431 | Only GPT-5.1 measured |
| Neither model has a result on the other 2 boards here | |||
Web designLike-for-likePublic boards, shown as published, kept out of the index31
| Benchmark | Gemini 3 Flash Preview | GPT-5.1 | Leader |
|---|---|---|---|
| Design Arena: websites | 1196 | 1187 | Gemini 3 Flash Preview |
| Design Arena: UI components | Not measured | 1166 | Only GPT-5.1 measured |
| Design Arena: game dev | 1166 | 1179 | GPT-5.1 |
| Design Arena: data viz | Not measured | 1204 | Only GPT-5.1 measured |
| Design Arena: 3D | 1184 | 1061 | Gemini 3 Flash Preview |
| Design Arena: all code categories | 1189 | 1171 | Gemini 3 Flash Preview |
| Design Arena: SVG | Not measured | 1149 | Only GPT-5.1 measured |
| Design Arena: ASCII art | Not measured | 1118 | Only GPT-5.1 measured |
| Neither model has a result on the other 1 board here | |||
GeneralLike-for-likePublic boards, shown as published, kept out of the index24
| Benchmark | Gemini 3 Flash Preview | GPT-5.1 | Leader |
|---|---|---|---|
| SAGE (Vals AI) | 51.8% | 43.2% | Gemini 3 Flash Preview |
| MedScribe (Vals AI) | 69.9% | 88.1% | GPT-5.1 |
| Vals Multimodal Index | 52.2% | Not measured | Only Gemini 3 Flash Preview measured |
| IFBench | 78.0% | 72.9% | Gemini 3 Flash Preview |
| Long context reasoning (AA-LCR) | 78.0% | 80.0% | GPT-5.1 |
| DTBench | 89.1% | 90.1% | GPT-5.1 |
| LMCA | 43.1% | 43.9% | GPT-5.1 |
| CL-bench | Not measured | 23.7% | Only GPT-5.1 measured |
| CL-bench Life | Not measured | 17.3% | Only GPT-5.1 measured |
| LMArena Text | Not measured | 1443 | Only GPT-5.1 measured |
| LMArena Text: instruction following | Not measured | 1443 | Only GPT-5.1 measured |
| LMArena Text: creative writing | Not measured | 1427 | Only GPT-5.1 measured |
| LMArena Vision | Not measured | 1250 | Only GPT-5.1 measured |
| LMArena Text: English | Not measured | 1451 | Only GPT-5.1 measured |
| LMArena Text: non-English | Not measured | 1431 | Only GPT-5.1 measured |
| LMArena Text: Chinese | Not measured | 1495 | Only GPT-5.1 measured |
| LMArena Text: German | Not measured | 1438 | Only GPT-5.1 measured |
| LMArena Text: Japanese | Not measured | 1453 | Only GPT-5.1 measured |
| LMArena Text: Korean | Not measured | 1401 | Only GPT-5.1 measured |
| LMArena Text: French | Not measured | 1450 | Only GPT-5.1 measured |
| LMArena Text: Spanish | Not measured | 1433 | Only GPT-5.1 measured |
| LMArena Text: Russian | Not measured | 1435 | Only GPT-5.1 measured |
| LMArena Text: Polish | Not measured | 1440 | Only GPT-5.1 measured |
| LMArena Text: multi-turn | Not measured | 1450 | Only GPT-5.1 measured |
| LMArena Text: longer queries | Not measured | 1448 | Only GPT-5.1 measured |
| LMArena Text: writing and language | Not measured | 1428 | Only GPT-5.1 measured |
| LMArena Text: entertainment and media | Not measured | 1415 | Only GPT-5.1 measured |
| LMArena Vision: English | Not measured | 1252 | Only GPT-5.1 measured |
| LMArena Vision: Chinese | Not measured | 1270 | Only GPT-5.1 measured |
| LMArena Vision: reading text | Not measured | 1255 | Only GPT-5.1 measured |
| LMArena Vision: humor | Not measured | 1263 | Only GPT-5.1 measured |
| LMArena Vision: captioning | Not measured | 1252 | Only GPT-5.1 measured |
| LMArena Vision: recognizing things | Not measured | 1232 | Only GPT-5.1 measured |
| LMArena Vision: creative writing | Not measured | 1266 | Only GPT-5.1 measured |
| LMArena Document | Not measured | 1403 | Only GPT-5.1 measured |
| Neither model has a result on the other 11 boards here | |||
Image generationNot comparablePublic boards, shown as published, kept out of the index0 boards, none shared
| Benchmark | Gemini 3 Flash Preview | GPT-5.1 | Leader |
|---|---|---|---|
| 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 Flash Preview costs less
Repository review
50K input + 3K output tokens
Gemini 3 Flash Preview costs less
Agent loop
200K input + 10K output tokens
Gemini 3 Flash 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.
| Specification | Google Gemini 3 Flash Preview | OpenAI GPT-5.1 |
|---|---|---|
| Maker | OpenAI | |
| Weights | No public weights listed | No public weights listed |
| Released | December 17, 2025 | November 13, 2025 |
| Context window | 1.05M | 400K |
| Input $/Mtok | $0.50 | $1.25 |
| Output $/Mtok | $3.00 | $10.00 |
| Coding index | 75.8 | 53.3 |
| Independent measurements behind it | 1 | 2 |
| Cost per solved task | $0.37 | $1.02 |
| Source | OpenRouter listing | OpenRouter listing |
Questions
Is Gemini 3 Flash Preview better than GPT-5.1 for coding?
Pick Gemini 3 Flash Preview for coding: it scores 75.8 on the Vibe Coding Index against 53.3 for GPT-5.1, though on 1 benchmark against 2. Pick GPT-5.1 when what matters is LiveCodeBench (Vals AI) or Vibe Code Bench (Vals AI), where it leads.
Which is cheaper, Gemini 3 Flash Preview or GPT-5.1?
Gemini 3 Flash Preview costs $0.50 per million input tokens and $3.00 per million output tokens; GPT-5.1 costs $1.25 and $10.00. Per solved SWE-bench Verified task, Gemini 3 Flash Preview costs $0.37 and GPT-5.1 $1.02.
Which has the bigger context window, Gemini 3 Flash Preview or GPT-5.1?
Gemini 3 Flash Preview, with 1.05M tokens against 400K.
How many benchmarks is the Gemini 3 Flash Preview vs GPT-5.1 comparison based on?
49 benchmarks have a result for both models as of October 21, 2026. Gemini 3 Flash Preview's coding index rests on 1 independent benchmark and GPT-5.1's on 2. Where only one model has a result, the page says so instead of naming a winner.