Gemini 3.1 Flash Lite Preview vs GPT-5.1-Codex-Mini
GPT-5.1-Codex-Mini leads Gemini 3.1 Flash Lite Preview on the Artificial Analysis Intelligence Index, 20.4 to 15.6, and Gemini 3.1 Flash Lite Preview costs 1.3x less per output token ($1.50 vs $2.00 per million). Updated October 21, 2026; 11 benchmarks have a result for both.
Gemini 3.1 Flash Lite Preview or GPT-5.1-Codex-Mini: which to pick
Only Gemini 3.1 Flash Lite Preview has a coding score, 22.7 on the Vibe Coding Index; GPT-5.1-Codex-Mini has none, so the two cannot be ranked on coding.
Pick GPT-5.1-Codex-Mini for work measured by AA Intelligence Index or Design Arena: websites, where it leads.
- Shared results
- 11
- Gemini 3.1 Flash Lite Preview only
- 68
- GPT-5.1-Codex-Mini only
- 11
- Like-for-like categories
- 3 of 9
Only benchmarks that tested both models count toward a pick; a result only one model has is shown but not compared.
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, six public coding benchmarks
No call
Only Gemini 3.1 Flash Lite Preview has a coding score, so no call is made.
One side not measured
Intelligence
AA Intelligence Index
GPT-5.1-Codex-Mini
GPT-5.1-Codex-Mini leads, 20.4 against 15.6.
Same board, both measured
Agentic work
AA Agentic Index
No call
Only Gemini 3.1 Flash Lite Preview has a AA Agentic Index result, 1.6.
Directional only
Reasoning
GPQA Diamond
No call
Only Gemini 3.1 Flash Lite Preview has a GPQA Diamond result, 81.1%.
Directional only
Math
AIME
No call
Only Gemini 3.1 Flash Lite Preview has a AIME result, 83.3%.
Directional only
Knowledge
MMLU Pro
No call
Only Gemini 3.1 Flash Lite Preview has a MMLU Pro result, 86.2%.
Directional only
Web design
Design Arena: websites
GPT-5.1-Codex-Mini
GPT-5.1-Codex-Mini leads, 1111 against 1083.
Same board, both measured
Long documents
Listed context window
Gemini 3.1 Flash Lite Preview
Gemini 3.1 Flash Lite Preview takes 1.05M tokens against 400K.
Listed by OpenRouter
Everyday cost
1K input + 500 output tokens
Gemini 3.1 Flash Lite Preview
Gemini 3.1 Flash Lite Preview $0.0010, GPT-5.1-Codex-Mini $0.0013 per turn.
List prices
Cost per solved task
One SWE-bench Verified task, solved
No call
Only Gemini 3.1 Flash Lite Preview has the number, $0.18.
Directional only
At a glance
- Coding index
- Gemini 3.1 Flash Lite Preview 22.7 from 3 benchmarks, GPT-5.1-Codex-Mini not benchmarked.
- Widest category
- Web design, 5.8 points apart on average over 8 shared benchmarks.
- Widest single gap
- Design Arena: SVG: Gemini 3.1 Flash Lite Preview 1052 against GPT-5.1-Codex-Mini 978, 9.3 points apart on a 0 to 100 scale.
- Output price
- Gemini 3.1 Flash Lite Preview $1.50 against GPT-5.1-Codex-Mini $2.00 per million output tokens, 1.3x apart.
- Context window
- Gemini 3.1 Flash Lite Preview takes 1.05M tokens, GPT-5.1-Codex-Mini 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 3.1 Flash Lite Preview | Bars | GPT-5.1-Codex-Mini | Ties |
|---|---|---|---|---|
| Coding | 2 | 0 | ||
| Intelligence | 0 | 1 | ||
| Web design | 3 | 5 | ||
| All shared boards | 5 | 6 |
CodingLike-for-likeSix of these boards feed the Vibe Coding Index20
| Benchmark | Gemini 3.1 Flash Lite Preview | GPT-5.1-Codex-Mini | Leader |
|---|---|---|---|
| LMArena WebDev | 1257 | 1244 | Gemini 3.1 Flash Lite Preview |
| AA Coding Index | 34.7 | Not measured | Only Gemini 3.1 Flash Lite Preview measured |
| LiveCodeBench (Vals AI) | 80.1% | Not measured | Only Gemini 3.1 Flash Lite Preview measured |
| SWE-bench Verified (Vals AI) | 62.8% | Not measured | Only Gemini 3.1 Flash Lite Preview measured |
| Vibe Code Bench (Vals AI) | 0.0% | Not measured | Only Gemini 3.1 Flash Lite Preview measured |
| Code migration (Vals AI) | 4.6% | Not measured | Only Gemini 3.1 Flash Lite Preview measured |
| ProgramBench (Vals AI) | 0.0% | Not measured | Only Gemini 3.1 Flash Lite Preview measured |
| Terminal-Bench 2.1 (Vals AI) | 34.1% | Not measured | Only Gemini 3.1 Flash Lite Preview measured |
| LiveCodeBench (Artificial Analysis run) | Not measured | 83.6% | Only GPT-5.1-Codex-Mini measured |
| Terminal-Bench Hard (Artificial Analysis run) | Not measured | 33.3% | Only GPT-5.1-Codex-Mini measured |
| Terminal-Bench | Not measured | 61.6% | Only GPT-5.1-Codex-Mini measured |
| ALE-Bench | 797.7 | Not measured | Only Gemini 3.1 Flash Lite Preview measured |
| LMArena Text: coding | 1400 | Not measured | Only Gemini 3.1 Flash Lite Preview measured |
| LMArena Text: software and IT | 1413 | Not measured | Only Gemini 3.1 Flash Lite Preview measured |
| LMArena WebDev: React | 1245 | Not measured | Only Gemini 3.1 Flash Lite Preview measured |
| LMArena WebDev: HTML | 1276 | 1253 | Gemini 3.1 Flash Lite Preview |
| LMArena WebDev: from an image | 1336 | Not measured | Only Gemini 3.1 Flash Lite Preview measured |
| SciCode | 4.6% | Not measured | Only Gemini 3.1 Flash Lite Preview measured |
| Neither model has a result on the other 21 boards here | |||
IntelligenceLike-for-likePublic boards, shown as published, kept out of the index01
| Benchmark | Gemini 3.1 Flash Lite Preview | GPT-5.1-Codex-Mini | Leader |
|---|---|---|---|
| AA Intelligence Index | 15.6 | 20.4 | GPT-5.1-Codex-Mini |
| Neither model has a result on the other 1 board here | |||
Agentic workDirectional onlyPublic boards, shown as published, kept out of the index6 boards, none shared
| Benchmark | Gemini 3.1 Flash Lite Preview | GPT-5.1-Codex-Mini | Leader |
|---|---|---|---|
| AA Agentic Index | 1.6 | Not measured | Only Gemini 3.1 Flash Lite Preview measured |
| Finance Agent (Vals AI) | 30.0% | Not measured | Only Gemini 3.1 Flash Lite Preview measured |
| Tax Agent Bench (Vals AI) | 3.1% | Not measured | Only Gemini 3.1 Flash Lite Preview measured |
| Legal Research Bench (Vals AI) | 3.4% | Not measured | Only Gemini 3.1 Flash Lite Preview measured |
| Excel Modeling Benchmark (Vals AI) | 8.6% | Not measured | Only Gemini 3.1 Flash Lite Preview measured |
| τ²-Bench Telecom | Not measured | 62.9% | Only GPT-5.1-Codex-Mini measured |
| Neither model has a result on the other 35 boards here | |||
ReasoningDirectional onlyPublic boards, shown as published, kept out of the index9 boards, none shared
| Benchmark | Gemini 3.1 Flash Lite Preview | GPT-5.1-Codex-Mini | Leader |
|---|---|---|---|
| GPQA Diamond | 81.1% | Not measured | Only Gemini 3.1 Flash Lite Preview measured |
| MMMU Pro (Vals AI) | 82.5% | Not measured | Only Gemini 3.1 Flash Lite Preview measured |
| GPQA Diamond (Artificial Analysis run) | Not measured | 81.3% | Only GPT-5.1-Codex-Mini measured |
| Humanity's Last Exam (Artificial Analysis run) | Not measured | 18.5% | Only GPT-5.1-Codex-Mini measured |
| LMArena Text: hard prompts | 1407 | Not measured | Only Gemini 3.1 Flash Lite Preview measured |
| LMArena Text: expert | 1398 | Not measured | Only Gemini 3.1 Flash Lite Preview measured |
| LMArena Text: hard prompts in English | 1403 | Not measured | Only Gemini 3.1 Flash Lite Preview measured |
| LMArena Vision: diagrams | 1242 | Not measured | Only Gemini 3.1 Flash Lite Preview measured |
| LMArena Vision: homework | 1271 | Not measured | Only Gemini 3.1 Flash Lite Preview measured |
| Neither model has a result on the other 13 boards here | |||
MathDirectional onlyPublic boards, shown as published, kept out of the index5 boards, none shared
| Benchmark | Gemini 3.1 Flash Lite Preview | GPT-5.1-Codex-Mini | Leader |
|---|---|---|---|
| AIME | 83.3% | Not measured | Only Gemini 3.1 Flash Lite Preview measured |
| AA Math Index | Not measured | 91.7 | Only GPT-5.1-Codex-Mini measured |
| AIME 2025 (Artificial Analysis run) | Not measured | 91.7% | Only GPT-5.1-Codex-Mini measured |
| LMArena Text: math | 1428 | Not measured | Only Gemini 3.1 Flash Lite Preview measured |
| LMArena Text: mathematical work | 1417 | Not measured | Only Gemini 3.1 Flash Lite Preview measured |
| Neither model has a result on the other 8 boards here | |||
KnowledgeDirectional onlyPublic boards, shown as published, kept out of the index13 boards, none shared
| Benchmark | Gemini 3.1 Flash Lite Preview | GPT-5.1-Codex-Mini | Leader |
|---|---|---|---|
| MMLU Pro | 86.2% | Not measured | Only Gemini 3.1 Flash Lite Preview measured |
| LegalBench (Vals AI) | 83.8% | Not measured | Only Gemini 3.1 Flash Lite Preview measured |
| CaseLaw (Vals AI) | 55.0% | Not measured | Only Gemini 3.1 Flash Lite Preview measured |
| CorpFin (Vals AI) | 59.4% | Not measured | Only Gemini 3.1 Flash Lite Preview measured |
| TaxEval (Vals AI) | 71.8% | Not measured | Only Gemini 3.1 Flash Lite Preview measured |
| MortgageTax (Vals AI) | 68.0% | Not measured | Only Gemini 3.1 Flash Lite Preview measured |
| MedCode (Vals AI) | 47.6% | Not measured | Only Gemini 3.1 Flash Lite Preview measured |
| MMLU Pro (Artificial Analysis run) | Not measured | 82.0% | Only GPT-5.1-Codex-Mini measured |
| LMArena Text: science | 1425 | Not measured | Only Gemini 3.1 Flash Lite Preview measured |
| LMArena Text: medicine and healthcare | 1428 | Not measured | Only Gemini 3.1 Flash Lite Preview measured |
| LMArena Text: legal and government | 1418 | Not measured | Only Gemini 3.1 Flash Lite Preview measured |
| LMArena Text: business and finance | 1389 | Not measured | Only Gemini 3.1 Flash Lite Preview measured |
| FACTS Benchmark Suite | 51.4% | Not measured | Only Gemini 3.1 Flash Lite Preview measured |
| Neither model has a result on the other 5 boards here | |||
Web designLike-for-likePublic boards, shown as published, kept out of the index35
| Benchmark | Gemini 3.1 Flash Lite Preview | GPT-5.1-Codex-Mini | Leader |
|---|---|---|---|
| Design Arena: websites | 1083 | 1111 | GPT-5.1-Codex-Mini |
| Design Arena: UI components | 1072 | 1081 | GPT-5.1-Codex-Mini |
| Design Arena: game dev | 1029 | 1092 | GPT-5.1-Codex-Mini |
| Design Arena: data viz | 1045 | 1097 | GPT-5.1-Codex-Mini |
| Design Arena: 3D | 1048 | 988 | Gemini 3.1 Flash Lite Preview |
| Design Arena: all code categories | 1072 | 1094 | GPT-5.1-Codex-Mini |
| Design Arena: SVG | 1052 | 978 | Gemini 3.1 Flash Lite Preview |
| Design Arena: ASCII art | 1167 | 1105 | Gemini 3.1 Flash Lite Preview |
| Neither model has a result on the other 1 board here | |||
GeneralDirectional onlyPublic boards, shown as published, kept out of the index30 boards, none shared
| Benchmark | Gemini 3.1 Flash Lite Preview | GPT-5.1-Codex-Mini | Leader |
|---|---|---|---|
| SAGE (Vals AI) | 49.5% | Not measured | Only Gemini 3.1 Flash Lite Preview measured |
| MedScribe (Vals AI) | 63.9% | Not measured | Only Gemini 3.1 Flash Lite Preview measured |
| Vals Multimodal Index | 41.4% | Not measured | Only Gemini 3.1 Flash Lite Preview measured |
| IFBench | Not measured | 67.9% | Only GPT-5.1-Codex-Mini measured |
| Long context reasoning (AA-LCR) | Not measured | 66.7% | Only GPT-5.1-Codex-Mini measured |
| LMArena Text | 1416 | Not measured | Only Gemini 3.1 Flash Lite Preview measured |
| LMArena Text: instruction following | 1377 | Not measured | Only Gemini 3.1 Flash Lite Preview measured |
| LMArena Text: creative writing | 1401 | Not measured | Only Gemini 3.1 Flash Lite Preview measured |
| LMArena Vision | 1240 | Not measured | Only Gemini 3.1 Flash Lite Preview measured |
| LMArena Text: English | 1414 | Not measured | Only Gemini 3.1 Flash Lite Preview measured |
| LMArena Text: non-English | 1410 | Not measured | Only Gemini 3.1 Flash Lite Preview measured |
| LMArena Text: Chinese | 1460 | Not measured | Only Gemini 3.1 Flash Lite Preview measured |
| LMArena Text: German | 1430 | Not measured | Only Gemini 3.1 Flash Lite Preview measured |
| LMArena Text: Japanese | 1413 | Not measured | Only Gemini 3.1 Flash Lite Preview measured |
| LMArena Text: Korean | 1392 | Not measured | Only Gemini 3.1 Flash Lite Preview measured |
| LMArena Text: French | 1424 | Not measured | Only Gemini 3.1 Flash Lite Preview measured |
| LMArena Text: Spanish | 1421 | Not measured | Only Gemini 3.1 Flash Lite Preview measured |
| LMArena Text: Russian | 1420 | Not measured | Only Gemini 3.1 Flash Lite Preview measured |
| LMArena Text: Polish | 1443 | Not measured | Only Gemini 3.1 Flash Lite Preview measured |
| LMArena Text: multi-turn | 1417 | Not measured | Only Gemini 3.1 Flash Lite Preview measured |
| LMArena Text: longer queries | 1394 | Not measured | Only Gemini 3.1 Flash Lite Preview measured |
| LMArena Text: writing and language | 1408 | Not measured | Only Gemini 3.1 Flash Lite Preview measured |
| LMArena Text: entertainment and media | 1386 | Not measured | Only Gemini 3.1 Flash Lite Preview measured |
| LMArena Vision: English | 1232 | Not measured | Only Gemini 3.1 Flash Lite Preview measured |
| LMArena Vision: Chinese | 1278 | Not measured | Only Gemini 3.1 Flash Lite Preview measured |
| LMArena Vision: reading text | 1246 | Not measured | Only Gemini 3.1 Flash Lite Preview measured |
| LMArena Vision: humor | 1266 | Not measured | Only Gemini 3.1 Flash Lite Preview measured |
| LMArena Vision: captioning | 1259 | Not measured | Only Gemini 3.1 Flash Lite Preview measured |
| LMArena Vision: recognizing things | 1308 | Not measured | Only Gemini 3.1 Flash Lite Preview measured |
| LMArena Vision: creative writing | 1248 | Not measured | Only Gemini 3.1 Flash Lite Preview measured |
| Neither model has a result on the other 16 boards here | |||
Image generationNot comparablePublic boards, shown as published, kept out of the index0 boards, none shared
| Benchmark | Gemini 3.1 Flash Lite Preview | GPT-5.1-Codex-Mini | 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 3.1 Flash Lite Preview costs less
Repository review
50K input + 3K output tokens
Gemini 3.1 Flash Lite Preview costs less
Agent loop
200K input + 10K output tokens
Gemini 3.1 Flash Lite 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 3.1 Flash Lite Preview | OpenAI GPT-5.1-Codex-Mini |
|---|---|---|
| Maker | OpenAI | |
| Weights | No public weights listed | No public weights listed |
| Released | March 3, 2026 | November 13, 2025 |
| Context window | 1.05M | 400K |
| Input $/Mtok | $0.25 | $0.25 |
| Output $/Mtok | $1.50 | $2.00 |
| Coding index | 22.7 | Not benchmarked |
| Independent measurements behind it | 3 | 1 |
| Cost per solved task | $0.18 | Not computable |
| Source | OpenRouter listing | OpenRouter listing |
Questions
Is Gemini 3.1 Flash Lite Preview better than GPT-5.1-Codex-Mini for coding?
Only Gemini 3.1 Flash Lite Preview has a coding score, 22.7 on the Vibe Coding Index; GPT-5.1-Codex-Mini has none, so the two cannot be ranked on coding. Pick GPT-5.1-Codex-Mini for work measured by AA Intelligence Index or Design Arena: websites, where it leads.
Which is cheaper, Gemini 3.1 Flash Lite Preview or GPT-5.1-Codex-Mini?
Gemini 3.1 Flash Lite Preview costs $0.25 per million input tokens and $1.50 per million output tokens; GPT-5.1-Codex-Mini costs $0.25 and $2.00. Cost per solved task is known for Gemini 3.1 Flash Lite Preview only.
Which has the bigger context window, Gemini 3.1 Flash Lite Preview or GPT-5.1-Codex-Mini?
Gemini 3.1 Flash Lite Preview, with 1.05M tokens against 400K.
How many benchmarks is the Gemini 3.1 Flash Lite Preview vs GPT-5.1-Codex-Mini comparison based on?
11 benchmarks have a result for both models as of October 21, 2026. Gemini 3.1 Flash Lite Preview's coding index rests on 3 independent benchmarks and GPT-5.1-Codex-Mini's on 1. Where only one model has a result, the page says so instead of naming a winner.