Gemini 3.8 Flash vs GPT-5 Mini
Updated October 21, 2026. 76 benchmarks have a result for both. Coding is ranked on the Vibe Coding Index; every other board is shown as published.
vs boards won of 76 shared
Decision reading
Pick Gemini 3.8 Flash for coding: it scores 70.5 on the Vibe Coding Index against 59.8 for GPT-5 Mini.
Pick GPT-5 Mini when output tokens cost 2.1x less, or when a solved task costs $0.08 against $2.74.
Model AGemini 3.8 FlashGoogle70.5/1002 independent benchmarks$2.74 per solved taskModel BGPT-5 MiniOpenAI59.8/1001 independent benchmark$0.08 per solved task
- Shared results
- 76
- Gemini 3.8 Flash only
- 50
- GPT-5 Mini only
- 22
- 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 3.8 Flash
Gemini 3.8 Flash scores 70.5 against 59.8.
2 and 1 benchmarks behind the scores
Intelligence
AA Intelligence Index
Gemini 3.8 Flash
Gemini 3.8 Flash leads, 40.9 against 20.6.
Same board, both measured
Agentic work
AA Agentic Index
No call
Only Gemini 3.8 Flash has a AA Agentic Index result, 40.2.
Directional only
Reasoning
GPQA Diamond
Gemini 3.8 Flash
Gemini 3.8 Flash leads, 94.4% against 80.3%.
Same board, both measured
Math
AIME
No call
Only GPT-5 Mini has a AIME result, 91.5%.
Directional only
Knowledge
MMLU Pro
Gemini 3.8 Flash
Gemini 3.8 Flash leads, 90.2% against 82.2%.
Same board, both measured
Web design
Design Arena: websites
Gemini 3.8 Flash
Gemini 3.8 Flash leads, 1301 against 1125.
Same board, both measured
General
Vals Index
No call
Only Gemini 3.8 Flash has a Vals Index result, 56.0%.
Directional only
Long documents
Listed context window
Gemini 3.8 Flash
Gemini 3.8 Flash takes 1.05M tokens against 400K.
Listed by OpenRouter
Everyday cost
1K input + 500 output tokens
GPT-5 Mini
Gemini 3.8 Flash $0.0029, GPT-5 Mini $0.0013 per turn.
List prices
Cost per solved task
One SWE-bench Verified task, solved
GPT-5 Mini
Gemini 3.8 Flash $2.74, GPT-5 Mini $0.08.
Published attempt cost and pass rate
At a glance
- Coding index
- Gemini 3.8 Flash 70.5 from 2 benchmarks, GPT-5 Mini 59.8 from 1 benchmark.
- Widest category
- Agentic work, 31.8 points apart on average over 1 shared benchmark.
- Widest single gap
- ARC-AGI-2: Gemini 3.8 Flash 89.2% against GPT-5 Mini 4.4%, 84.7 points apart on a 0 to 100 scale.
- Output price
- Gemini 3.8 Flash $4.125 against GPT-5 Mini $2.00 per million output tokens, 2.1x apart.
- Context window
- Gemini 3.8 Flash takes 1.05M tokens, GPT-5 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 3.8 Flash | Bars | GPT-5 Mini | Ties |
|---|---|---|---|---|
| Coding | 7 | 0 | ||
| Intelligence | 2 | 0 | ||
| Agentic work | 1 | 0 | ||
| Reasoning | 14 | 0 | ||
| Math | 6 | 0 | ||
| Knowledge | 8 | 2 | ||
| Web design | 8 | 0 | ||
| General | 27 | 1 | ||
| All shared boards | 73 | 3 |
CodingLike-for-likeFour of these boards feed the Vibe Coding Index70
| Benchmark | Gemini 3.8 Flash | GPT-5 Mini | Leader |
|---|---|---|---|
| SWE-bench Verified | Not measured | 59.8% | Only GPT-5 Mini measured |
| SWE-bench Multilingual | Not measured | 39.7% | Only GPT-5 Mini measured |
| LiveBench coding | 82.2% | Not measured | Only Gemini 3.8 Flash measured |
| LMArena WebDev | 1585 | Not measured | Only Gemini 3.8 Flash measured |
| AA Coding Index | 76.3 | Not measured | Only Gemini 3.8 Flash measured |
| LiveCodeBench (Vals AI) | 89.5% | 86.6% | Gemini 3.8 Flash |
| SWE-bench Verified (Vals AI) | 80.0% | 60.8% | Gemini 3.8 Flash |
| Terminal-Bench 4 (Vals AI) | 19.7% | Not measured | Only Gemini 3.8 Flash measured |
| Vibe Code Bench (Vals AI) | 78.7% | 14.2% | Gemini 3.8 Flash |
| Code migration (Vals AI) | 36.5% | Not measured | Only Gemini 3.8 Flash measured |
| ProgramBench (Vals AI) | 1.0% | Not measured | Only Gemini 3.8 Flash measured |
| IOI (Vals AI) | 56.9% | Not measured | Only Gemini 3.8 Flash measured |
| Terminal-Bench 2.1 (Vals AI) | 81.3% | Not measured | Only Gemini 3.8 Flash measured |
| SWE-bench Multimodal (Vals AI) | 40.8% | Not measured | Only Gemini 3.8 Flash measured |
| Vibe Code Bench 1-100 (Vals AI) | 18.8% | Not measured | Only Gemini 3.8 Flash measured |
| SkillsBench (Vals AI) | 58.0% | Not measured | Only Gemini 3.8 Flash measured |
| CyberBench (Vals AI) | 43.8% | Not measured | Only Gemini 3.8 Flash measured |
| LiveCodeBench (Artificial Analysis run) | Not measured | 83.8% | Only GPT-5 Mini measured |
| SciCode | 56.6% | 39.0% | Gemini 3.8 Flash |
| Terminal-Bench Hard (Artificial Analysis run) | Not measured | 33.3% | Only GPT-5 Mini measured |
| Terminal-Bench | Not measured | 34.8% | Only GPT-5 Mini measured |
| FrontierCode | 41.2% | Not measured | Only Gemini 3.8 Flash measured |
| FrontierSWE | 19.6% | Not measured | Only Gemini 3.8 Flash measured |
| WeirdML | 84.8% | 52.7% | Gemini 3.8 Flash |
| ALE-Bench | 1269.7 | Not measured | Only Gemini 3.8 Flash measured |
| LMArena Text: coding | 1508 | 1406 | Gemini 3.8 Flash |
| LMArena Text: software and IT | 1507 | 1394 | Gemini 3.8 Flash |
| LMArena WebDev: React | 1577 | Not measured | Only Gemini 3.8 Flash measured |
| LMArena WebDev: HTML | 1616 | Not measured | Only Gemini 3.8 Flash measured |
| LMArena WebDev: from an image | 1593 | Not measured | Only Gemini 3.8 Flash measured |
| Neither model has a result on the other 8 boards here | |||
IntelligenceLike-for-likePublic boards, shown as published, kept out of the index20
| Benchmark | Gemini 3.8 Flash | GPT-5 Mini | Leader |
|---|---|---|---|
| AA Intelligence Index | 40.9 | 20.6 | Gemini 3.8 Flash |
| Epoch Capabilities Index | 157.4 | 145.3 | Gemini 3.8 Flash |
Agentic workLike-for-likePublic boards, shown as published, kept out of the index10
| Benchmark | Gemini 3.8 Flash | GPT-5 Mini | Leader |
|---|---|---|---|
| AA Agentic Index | 40.2 | Not measured | Only Gemini 3.8 Flash measured |
| Design Arena: agents building web apps | 1238 | Not measured | Only Gemini 3.8 Flash measured |
| Design Arena: agents building full-stack apps | 1244 | Not measured | Only Gemini 3.8 Flash measured |
| Design Arena: agents building mobile apps | 1236 | Not measured | Only Gemini 3.8 Flash measured |
| Design Arena: agents building Android apps | 1078 | Not measured | Only Gemini 3.8 Flash measured |
| Design Arena: agents building Godot games | 1273 | Not measured | Only Gemini 3.8 Flash measured |
| Design Arena: PowerPoint slides | 1178 | Not measured | Only Gemini 3.8 Flash measured |
| Design Arena: spreadsheets | 1052 | Not measured | Only Gemini 3.8 Flash measured |
| LiveBench research | 79.1% | Not measured | Only Gemini 3.8 Flash measured |
| LiveBench browser | 64.0% | Not measured | Only Gemini 3.8 Flash measured |
| LiveBench long agentic | 30.1% | Not measured | Only Gemini 3.8 Flash measured |
| SREBench (Vals AI) | 11.1% | Not measured | Only Gemini 3.8 Flash measured |
| Finance Agent (Vals AI) | 61.4% | Not measured | Only Gemini 3.8 Flash measured |
| Tax Agent Bench (Vals AI) | 32.1% | Not measured | Only Gemini 3.8 Flash measured |
| Legal Research Bench (Vals AI) | 38.9% | Not measured | Only Gemini 3.8 Flash measured |
| Harvey's Legal Agent Benchmark (Vals AI) | 12.1% | Not measured | Only Gemini 3.8 Flash measured |
| Excel Modeling Benchmark (Vals AI) | 72.2% | Not measured | Only Gemini 3.8 Flash measured |
| BioMysteryBench (Vals AI) | 62.2% | Not measured | Only Gemini 3.8 Flash measured |
| Terminal-Bench-Science (Vals AI) | 8.6% | Not measured | Only Gemini 3.8 Flash measured |
| Vals Science Index | 35.8% | Not measured | Only Gemini 3.8 Flash measured |
| Time Horizon Index (Vals AI) | 18.8% | Not measured | Only Gemini 3.8 Flash measured |
| CUA-bench (Vals AI) | 4.2% | Not measured | Only Gemini 3.8 Flash measured |
| τ²-Bench Telecom | Not measured | 71.1% | Only GPT-5 Mini measured |
| APEX-Agents | 64.3% | Not measured | Only Gemini 3.8 Flash measured |
| Remote Labor Index | 5.8% | Not measured | Only Gemini 3.8 Flash measured |
| Vending-Bench 2 | $5,094 | -$31 | Gemini 3.8 Flash |
| Neither model has a result on the other 13 boards here | |||
ReasoningLike-for-likePublic boards, shown as published, kept out of the index140
| Benchmark | Gemini 3.8 Flash | GPT-5 Mini | Leader |
|---|---|---|---|
| GPQA Diamond | 94.4% | 80.3% | Gemini 3.8 Flash |
| LiveBench reasoning | 89.3% | Not measured | Only Gemini 3.8 Flash measured |
| MysteryMechanism (Vals AI) | 36.5% | Not measured | Only Gemini 3.8 Flash measured |
| MMMU Pro (Vals AI) | 89.1% | 78.9% | Gemini 3.8 Flash |
| GPQA Diamond (Artificial Analysis run) | 95.3% | 82.8% | Gemini 3.8 Flash |
| Humanity's Last Exam (Artificial Analysis run) | 47.8% | 21.5% | Gemini 3.8 Flash |
| GPQA Diamond (Epoch AI run) | 95.4% | 75.0% | Gemini 3.8 Flash |
| ARC-AGI | 98.5% | 54.3% | Gemini 3.8 Flash |
| ARC-AGI-2 | 89.2% | 4.4% | Gemini 3.8 Flash |
| Chess puzzles | 58.0% | 24.0% | Gemini 3.8 Flash |
| Mystery game puzzles | 47.0% | 10.0% | Gemini 3.8 Flash |
| VPCT | Not measured | 40.2% | Only GPT-5 Mini measured |
| LMArena Text: hard prompts | 1509 | 1380 | Gemini 3.8 Flash |
| LMArena Text: expert | 1526 | 1379 | Gemini 3.8 Flash |
| LMArena Text: hard prompts in English | 1504 | 1383 | Gemini 3.8 Flash |
| LMArena Vision: diagrams | 1345 | 1202 | Gemini 3.8 Flash |
| LMArena Vision: homework | 1351 | 1210 | Gemini 3.8 Flash |
| Neither model has a result on the other 4 boards here | |||
MathLike-for-likePublic boards, shown as published, kept out of the index60
| Benchmark | Gemini 3.8 Flash | GPT-5 Mini | Leader |
|---|---|---|---|
| AIME | Not measured | 91.5% | Only GPT-5 Mini measured |
| MATH 500 (Vals AI) | Not measured | 94.8% | Only GPT-5 Mini measured |
| MGSM (Vals AI) | Not measured | 92.6% | Only GPT-5 Mini measured |
| AA Math Index | Not measured | 90.7 | Only GPT-5 Mini measured |
| AIME 2025 (Artificial Analysis run) | Not measured | 90.7% | Only GPT-5 Mini measured |
| OTIS Mock AIME | 98.9% | 86.7% | Gemini 3.8 Flash |
| FrontierMath, tiers 1 to 3 | 68.4% | 46.7% | Gemini 3.8 Flash |
| FrontierMath, tier 4 | 22.0% | 12.2% | Gemini 3.8 Flash |
| ProofBench | 48.0% | 9.0% | Gemini 3.8 Flash |
| MATH level 5 | Not measured | 97.8% | Only GPT-5 Mini measured |
| LMArena Text: math | 1532 | 1378 | Gemini 3.8 Flash |
| LMArena Text: mathematical work | 1519 | 1380 | Gemini 3.8 Flash |
| Neither model has a result on the other 1 board here | |||
KnowledgeLike-for-likePublic boards, shown as published, kept out of the index82
| Benchmark | Gemini 3.8 Flash | GPT-5 Mini | Leader |
|---|---|---|---|
| MMLU Pro | 90.2% | 82.2% | Gemini 3.8 Flash |
| LegalBench (Vals AI) | 87.0% | 81.8% | Gemini 3.8 Flash |
| CaseLaw (Vals AI) | Not measured | 68.5% | Only GPT-5 Mini measured |
| CorpFin (Vals AI) | Not measured | 60.2% | Only GPT-5 Mini measured |
| TaxEval (Vals AI) | 74.5% | 75.2% | GPT-5 Mini |
| MortgageTax (Vals AI) | 65.3% | 66.9% | GPT-5 Mini |
| MedQA (Vals AI) | Not measured | 96.1% | Only GPT-5 Mini measured |
| MedCode (Vals AI) | 48.1% | 43.0% | Gemini 3.8 Flash |
| MMLU Pro (Artificial Analysis run) | Not measured | 83.7% | Only GPT-5 Mini measured |
| SimpleQA Verified | 69.7% | 21.6% | Gemini 3.8 Flash |
| LMArena Text: science | 1523 | 1371 | Gemini 3.8 Flash |
| LMArena Text: medicine and healthcare | 1508 | 1380 | Gemini 3.8 Flash |
| LMArena Text: legal and government | 1497 | 1375 | Gemini 3.8 Flash |
| LMArena Text: business and finance | 1479 | 1358 | Gemini 3.8 Flash |
| Neither model has a result on the other 3 boards here | |||
Web designLike-for-likePublic boards, shown as published, kept out of the index80
| Benchmark | Gemini 3.8 Flash | GPT-5 Mini | Leader |
|---|---|---|---|
| Design Arena: websites | 1301 | 1125 | Gemini 3.8 Flash |
| Design Arena: UI components | 1318 | 1106 | Gemini 3.8 Flash |
| Design Arena: game dev | 1305 | 1130 | Gemini 3.8 Flash |
| Design Arena: data viz | 1269 | 1131 | Gemini 3.8 Flash |
| Design Arena: 3D | 1295 | 1037 | Gemini 3.8 Flash |
| Design Arena: all code categories | 1304 | 1115 | Gemini 3.8 Flash |
| Design Arena: SVG | 1295 | 1091 | Gemini 3.8 Flash |
| Design Arena: ASCII art | 1264 | 1124 | Gemini 3.8 Flash |
| LiveBench design | 72.7% | Not measured | Only Gemini 3.8 Flash measured |
GeneralLike-for-likePublic boards, shown as published, kept out of the index271
| Benchmark | Gemini 3.8 Flash | GPT-5 Mini | Leader |
|---|---|---|---|
| Vals Index | 56.0% | Not measured | Only Gemini 3.8 Flash measured |
| LiveBench data analysis | 54.0% | Not measured | Only Gemini 3.8 Flash measured |
| Public Benefits Bench (Vals AI) | 65.3% | Not measured | Only Gemini 3.8 Flash measured |
| SAGE (Vals AI) | 35.1% | 43.0% | GPT-5 Mini |
| MedScribe (Vals AI) | 84.5% | 80.6% | Gemini 3.8 Flash |
| IFBench | Not measured | 75.4% | Only GPT-5 Mini measured |
| Long context reasoning (AA-LCR) | 84.0% | 72.3% | Gemini 3.8 Flash |
| DTBench | 95.7% | 80.5% | Gemini 3.8 Flash |
| LMCA | 52.9% | 34.2% | Gemini 3.8 Flash |
| Fiction.LiveBench | Not measured | 69.4% | Only GPT-5 Mini measured |
| Creative writing (Lech Mazur) | Not measured | 83.1% | Only GPT-5 Mini measured |
| Surface Evolver Bench | 76.9% | Not measured | Only Gemini 3.8 Flash measured |
| Furniture assembly | 31.7% | Not measured | Only Gemini 3.8 Flash measured |
| LMArena Text | 1499 | 1373 | Gemini 3.8 Flash |
| LMArena Text: instruction following | 1492 | 1357 | Gemini 3.8 Flash |
| LMArena Text: creative writing | 1488 | 1325 | Gemini 3.8 Flash |
| LMArena Vision | 1315 | 1202 | Gemini 3.8 Flash |
| LMArena Text: English | 1498 | 1379 | Gemini 3.8 Flash |
| LMArena Text: non-English | 1491 | 1363 | Gemini 3.8 Flash |
| LMArena Text: Chinese | 1553 | 1386 | Gemini 3.8 Flash |
| LMArena Text: German | 1501 | 1366 | Gemini 3.8 Flash |
| LMArena Text: Japanese | 1507 | 1341 | Gemini 3.8 Flash |
| LMArena Text: Korean | 1464 | 1308 | Gemini 3.8 Flash |
| LMArena Text: French | 1496 | 1386 | Gemini 3.8 Flash |
| LMArena Text: Spanish | 1487 | 1354 | Gemini 3.8 Flash |
| LMArena Text: Russian | 1514 | 1362 | Gemini 3.8 Flash |
| LMArena Text: Polish | 1497 | 1378 | Gemini 3.8 Flash |
| LMArena Text: multi-turn | 1503 | 1363 | Gemini 3.8 Flash |
| LMArena Text: longer queries | 1507 | 1355 | Gemini 3.8 Flash |
| LMArena Text: writing and language | 1494 | 1344 | Gemini 3.8 Flash |
| LMArena Text: entertainment and media | 1480 | 1340 | Gemini 3.8 Flash |
| LMArena Vision: English | 1318 | 1216 | Gemini 3.8 Flash |
| LMArena Vision: Chinese | 1416 | 1214 | Gemini 3.8 Flash |
| LMArena Vision: reading text | 1333 | 1199 | Gemini 3.8 Flash |
| LMArena Vision: humor | 1321 | 1205 | Gemini 3.8 Flash |
| LMArena Vision: captioning | Not measured | 1217 | Only GPT-5 Mini measured |
| LMArena Vision: recognizing things | Not measured | 1226 | Only GPT-5 Mini measured |
| LMArena Vision: creative writing | 1299 | 1181 | Gemini 3.8 Flash |
| Neither model has a result on the other 8 boards here | |||
Image generationNot comparablePublic boards, shown as published, kept out of the index0 boards, none shared
| Benchmark | Gemini 3.8 Flash | GPT-5 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 3.8 Flash$0.0029Fits in one request
GPT-5 Mini$0.0013Fits in one request
GPT-5 Mini costs less
Repository review
50K input + 3K output tokens
Gemini 3.8 Flash$0.054Fits in one request
GPT-5 Mini$0.018Fits in one request
GPT-5 Mini costs less
Agent loop
200K input + 10K output tokens
Gemini 3.8 Flash$0.206Fits in one request
GPT-5 Mini$0.070Fits in one request
GPT-5 Mini 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 3.8 Flash | OpenAI GPT-5 Mini |
|---|---|---|
| Maker | OpenAI | |
| Weights | No public weights listed | No public weights listed |
| Released | September 2, 2026 | August 7, 2025 |
| Context window | 1.05M | 400K |
| Input $/Mtok | $0.825 | $0.25 |
| Output $/Mtok | $4.125 | $2.00 |
| Coding index | 70.5 | 59.8 |
| Independent measurements behind it | 2 | 1 |
| Cost per solved task | $2.74 | $0.08 |
| Source | OpenRouter listing | OpenRouter listing |
Questions
Is Gemini 3.8 Flash better than GPT-5 Mini for coding?
Pick Gemini 3.8 Flash for coding: it scores 70.5 on the Vibe Coding Index against 59.8 for GPT-5 Mini. Pick GPT-5 Mini when output tokens cost 2.1x less, or when a solved task costs $0.08 against $2.74.
Which is cheaper, Gemini 3.8 Flash or GPT-5 Mini?
Gemini 3.8 Flash costs $0.825 per million input tokens and $4.125 per million output tokens; GPT-5 Mini costs $0.25 and $2.00. Per solved SWE-bench Verified task, Gemini 3.8 Flash costs $2.74 and GPT-5 Mini $0.08.
Which has the bigger context window, Gemini 3.8 Flash or GPT-5 Mini?
Gemini 3.8 Flash, with 1.05M tokens against 400K.
How many benchmarks is the Gemini 3.8 Flash vs GPT-5 Mini comparison based on?
76 benchmarks have a result for both models as of October 21, 2026. Gemini 3.8 Flash's coding index rests on 2 independent benchmarks and GPT-5 Mini's on 1. Where only one model has a result, the page says so instead of naming a winner.