Gemini 2.5 Pro vs Gemini 3.8 Flash
Updated October 21, 2026. 69 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 69 shared
Decision reading
Pick Gemini 3.8 Flash for coding: it scores 70.5 on the Vibe Coding Index against 37.0 for Gemini 2.5 Pro.
Pick Gemini 2.5 Pro when a solved task costs $0.64 against $2.74, or when what matters is MortgageTax (Vals AI) or MedCode (Vals AI), where it leads.
Model AGemini 2.5 ProGoogle37.0/1002 independent benchmarks$0.64 per solved taskModel BGemini 3.8 FlashGoogle70.5/1002 independent benchmarks$2.74 per solved task
- Shared results
- 69
- Gemini 2.5 Pro only
- 18
- Gemini 3.8 Flash only
- 57
- 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 37.0.
2 benchmarks behind each score
Intelligence
AA Intelligence Index
Gemini 3.8 Flash
Gemini 3.8 Flash leads, 40.9 against 16.1.
Same board, both measured
Agentic work
AA Agentic Index
Gemini 3.8 Flash
Gemini 3.8 Flash leads, 40.2 against 1.6.
Same board, both measured
Reasoning
GPQA Diamond
No call
Only Gemini 3.8 Flash has a GPQA Diamond result, 94.4%.
Directional only
Knowledge
MMLU Pro
No call
Only Gemini 3.8 Flash has a MMLU Pro result, 90.2%.
Directional only
Web design
Design Arena: websites
Gemini 3.8 Flash
Gemini 3.8 Flash leads, 1301 against 1167.
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
No call
Both take 1.05M tokens.
Listed by OpenRouter
Everyday cost
1K input + 500 output tokens
Gemini 3.8 Flash
Gemini 2.5 Pro $0.0063, Gemini 3.8 Flash $0.0029 per turn.
List prices
Cost per solved task
One SWE-bench Verified task, solved
Gemini 2.5 Pro
Gemini 2.5 Pro $0.64, Gemini 3.8 Flash $2.74.
Published attempt cost and pass rate
At a glance
- Coding index
- Gemini 2.5 Pro 37.0 from 2 benchmarks, Gemini 3.8 Flash 70.5 from 2 benchmarks.
- Widest category
- Coding, 36.9 points apart on average over 10 shared benchmarks.
- Widest single gap
- ARC-AGI-2: Gemini 2.5 Pro 4.9% against Gemini 3.8 Flash 89.2%, 84.3 points apart on a 0 to 100 scale.
- Output price
- Gemini 2.5 Pro $10.00 against Gemini 3.8 Flash $4.125 per million output tokens, 2.4x apart.
- Context window
- Both take 1.05M tokens.
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 2.5 Pro | Bars | Gemini 3.8 Flash | Ties |
|---|---|---|---|---|
| Coding | 0 | 10 | ||
| Intelligence | 0 | 2 | ||
| Agentic work | 0 | 2 | ||
| Reasoning | 0 | 10 | ||
| Math | 0 | 5 | ||
| Knowledge | 2 | 4 | ||
| Web design | 0 | 6 | ||
| General | 1 | 27 | ||
| All shared boards | 3 | 66 |
CodingLike-for-likeFour of these boards feed the Vibe Coding Index010
| Benchmark | Gemini 2.5 Pro | Gemini 3.8 Flash | Leader |
|---|---|---|---|
| SWE-bench Verified | 53.6% | Not measured | Only Gemini 2.5 Pro measured |
| LiveBench coding | Not measured | 82.2% | Only Gemini 3.8 Flash measured |
| LMArena WebDev | 1226 | 1585 | Gemini 3.8 Flash |
| AA Coding Index | 33.3 | 76.3 | Gemini 3.8 Flash |
| LiveCodeBench (Vals AI) | Not measured | 89.5% | Only Gemini 3.8 Flash measured |
| SWE-bench Verified (Vals AI) | 54.4% | 80.0% | Gemini 3.8 Flash |
| Terminal-Bench 4 (Vals AI) | Not measured | 19.7% | Only Gemini 3.8 Flash measured |
| Vibe Code Bench (Vals AI) | 0.4% | 78.7% | Gemini 3.8 Flash |
| Code migration (Vals AI) | Not measured | 36.5% | Only Gemini 3.8 Flash measured |
| ProgramBench (Vals AI) | Not measured | 1.0% | Only Gemini 3.8 Flash measured |
| IOI (Vals AI) | Not measured | 56.9% | Only Gemini 3.8 Flash measured |
| Terminal-Bench 2.1 (Vals AI) | Not measured | 81.3% | Only Gemini 3.8 Flash measured |
| SWE-bench Multimodal (Vals AI) | Not measured | 40.8% | Only Gemini 3.8 Flash measured |
| Vibe Code Bench 1-100 (Vals AI) | Not measured | 18.8% | Only Gemini 3.8 Flash measured |
| SkillsBench (Vals AI) | Not measured | 58.0% | Only Gemini 3.8 Flash measured |
| CyberBench (Vals AI) | Not measured | 43.8% | Only Gemini 3.8 Flash measured |
| LiveCodeBench (Artificial Analysis run) | 80.1% | Not measured | Only Gemini 2.5 Pro measured |
| SciCode | 46.3% | 56.6% | Gemini 3.8 Flash |
| Terminal-Bench Hard (Artificial Analysis run) | 26.5% | Not measured | Only Gemini 2.5 Pro measured |
| Terminal-Bench | 32.6% | Not measured | Only Gemini 2.5 Pro measured |
| FrontierCode | Not measured | 41.2% | Only Gemini 3.8 Flash measured |
| FrontierSWE | Not measured | 19.6% | Only Gemini 3.8 Flash measured |
| GSO-Bench | 3.9% | Not measured | Only Gemini 2.5 Pro measured |
| WeirdML | 54.0% | 84.8% | Gemini 3.8 Flash |
| ALE-Bench | Not measured | 1269.7 | Only Gemini 3.8 Flash measured |
| LMArena Text: coding | 1452 | 1508 | Gemini 3.8 Flash |
| LMArena Text: software and IT | 1459 | 1507 | Gemini 3.8 Flash |
| LMArena WebDev: React | Not measured | 1577 | Only Gemini 3.8 Flash measured |
| LMArena WebDev: HTML | 1235 | 1616 | Gemini 3.8 Flash |
| LMArena WebDev: from an image | 1285 | 1593 | Gemini 3.8 Flash |
| Neither model has a result on the other 8 boards here | |||
IntelligenceLike-for-likePublic boards, shown as published, kept out of the index02
| Benchmark | Gemini 2.5 Pro | Gemini 3.8 Flash | Leader |
|---|---|---|---|
| AA Intelligence Index | 16.1 | 40.9 | Gemini 3.8 Flash |
| Epoch Capabilities Index | 145.1 | 157.4 | Gemini 3.8 Flash |
Agentic workLike-for-likePublic boards, shown as published, kept out of the index02
| Benchmark | Gemini 2.5 Pro | Gemini 3.8 Flash | Leader |
|---|---|---|---|
| AA Agentic Index | 1.6 | 40.2 | Gemini 3.8 Flash |
| Design Arena: agents building web apps | Not measured | 1238 | Only Gemini 3.8 Flash measured |
| Design Arena: agents building full-stack apps | Not measured | 1244 | Only Gemini 3.8 Flash measured |
| Design Arena: agents building mobile apps | Not measured | 1236 | Only Gemini 3.8 Flash measured |
| Design Arena: agents building Android apps | Not measured | 1078 | Only Gemini 3.8 Flash measured |
| Design Arena: agents building Godot games | Not measured | 1273 | Only Gemini 3.8 Flash measured |
| Design Arena: PowerPoint slides | Not measured | 1178 | Only Gemini 3.8 Flash measured |
| Design Arena: spreadsheets | Not measured | 1052 | Only Gemini 3.8 Flash measured |
| LiveBench research | Not measured | 79.1% | Only Gemini 3.8 Flash measured |
| LiveBench browser | Not measured | 64.0% | Only Gemini 3.8 Flash measured |
| LiveBench long agentic | Not measured | 30.1% | Only Gemini 3.8 Flash measured |
| SREBench (Vals AI) | Not measured | 11.1% | Only Gemini 3.8 Flash measured |
| Finance Agent (Vals AI) | Not measured | 61.4% | Only Gemini 3.8 Flash measured |
| Tax Agent Bench (Vals AI) | Not measured | 32.1% | Only Gemini 3.8 Flash measured |
| Legal Research Bench (Vals AI) | Not measured | 38.9% | Only Gemini 3.8 Flash measured |
| Harvey's Legal Agent Benchmark (Vals AI) | Not measured | 12.1% | Only Gemini 3.8 Flash measured |
| Excel Modeling Benchmark (Vals AI) | Not measured | 72.2% | Only Gemini 3.8 Flash measured |
| BioMysteryBench (Vals AI) | Not measured | 62.2% | Only Gemini 3.8 Flash measured |
| Terminal-Bench-Science (Vals AI) | Not measured | 8.6% | Only Gemini 3.8 Flash measured |
| Vals Science Index | Not measured | 35.8% | Only Gemini 3.8 Flash measured |
| Time Horizon Index (Vals AI) | Not measured | 18.8% | Only Gemini 3.8 Flash measured |
| CUA-bench (Vals AI) | Not measured | 4.2% | Only Gemini 3.8 Flash measured |
| τ²-Bench Telecom | 54.1% | Not measured | Only Gemini 2.5 Pro measured |
| APEX-Agents | Not measured | 64.3% | Only Gemini 3.8 Flash measured |
| Remote Labor Index | Not measured | 5.8% | Only Gemini 3.8 Flash measured |
| GDPval | 23.3% | Not measured | Only Gemini 2.5 Pro measured |
| DeepResearch Bench | 41.5% | Not measured | Only Gemini 2.5 Pro measured |
| Vending-Bench 2 | $574 | $5,094 | Gemini 3.8 Flash |
| Neither model has a result on the other 11 boards here | |||
ReasoningLike-for-likePublic boards, shown as published, kept out of the index010
| Benchmark | Gemini 2.5 Pro | Gemini 3.8 Flash | Leader |
|---|---|---|---|
| GPQA Diamond | Not measured | 94.4% | Only Gemini 3.8 Flash measured |
| LiveBench reasoning | Not measured | 89.3% | Only Gemini 3.8 Flash measured |
| MysteryMechanism (Vals AI) | Not measured | 36.5% | Only Gemini 3.8 Flash measured |
| MMMU Pro (Vals AI) | Not measured | 89.1% | Only Gemini 3.8 Flash measured |
| GPQA Diamond (Artificial Analysis run) | 84.4% | 95.3% | Gemini 3.8 Flash |
| Humanity's Last Exam (Artificial Analysis run) | 22.5% | 47.8% | Gemini 3.8 Flash |
| GPQA Diamond (Epoch AI run) | 85.3% | 95.4% | Gemini 3.8 Flash |
| ARC-AGI | 41.0% | 98.5% | Gemini 3.8 Flash |
| ARC-AGI-2 | 4.9% | 89.2% | Gemini 3.8 Flash |
| Chess puzzles | Not measured | 58.0% | Only Gemini 3.8 Flash measured |
| Mystery game puzzles | Not measured | 47.0% | Only Gemini 3.8 Flash measured |
| LMArena Text: hard prompts | 1455 | 1509 | Gemini 3.8 Flash |
| LMArena Text: expert | 1452 | 1526 | Gemini 3.8 Flash |
| LMArena Text: hard prompts in English | 1453 | 1504 | Gemini 3.8 Flash |
| LMArena Vision: diagrams | 1274 | 1345 | Gemini 3.8 Flash |
| LMArena Vision: homework | 1281 | 1351 | Gemini 3.8 Flash |
| Neither model has a result on the other 5 boards here | |||
MathLike-for-likePublic boards, shown as published, kept out of the index05
| Benchmark | Gemini 2.5 Pro | Gemini 3.8 Flash | Leader |
|---|---|---|---|
| AA Math Index | 87.7 | Not measured | Only Gemini 2.5 Pro measured |
| AIME 2025 (Artificial Analysis run) | 87.7% | Not measured | Only Gemini 2.5 Pro measured |
| OTIS Mock AIME | 84.7% | 98.9% | Gemini 3.8 Flash |
| FrontierMath, tiers 1 to 3 | 24.6% | 68.4% | Gemini 3.8 Flash |
| FrontierMath, tier 4 | 0.0% | 22.0% | Gemini 3.8 Flash |
| ProofBench | Not measured | 48.0% | Only Gemini 3.8 Flash measured |
| LMArena Text: math | 1450 | 1532 | Gemini 3.8 Flash |
| LMArena Text: mathematical work | 1454 | 1519 | Gemini 3.8 Flash |
| Neither model has a result on the other 5 boards here | |||
KnowledgeLike-for-likePublic boards, shown as published, kept out of the index24
| Benchmark | Gemini 2.5 Pro | Gemini 3.8 Flash | Leader |
|---|---|---|---|
| MMLU Pro | Not measured | 90.2% | Only Gemini 3.8 Flash measured |
| LegalBench (Vals AI) | Not measured | 87.0% | Only Gemini 3.8 Flash measured |
| CaseLaw (Vals AI) | 63.9% | Not measured | Only Gemini 2.5 Pro measured |
| CorpFin (Vals AI) | 60.8% | Not measured | Only Gemini 2.5 Pro measured |
| TaxEval (Vals AI) | Not measured | 74.5% | Only Gemini 3.8 Flash measured |
| MortgageTax (Vals AI) | 68.9% | 65.3% | Gemini 2.5 Pro |
| MedCode (Vals AI) | 50.6% | 48.1% | Gemini 2.5 Pro |
| MMLU Pro (Artificial Analysis run) | 86.2% | Not measured | Only Gemini 2.5 Pro measured |
| SimpleQA Verified | Not measured | 69.7% | Only Gemini 3.8 Flash measured |
| LMArena Text: science | 1480 | 1523 | Gemini 3.8 Flash |
| LMArena Text: medicine and healthcare | 1476 | 1508 | Gemini 3.8 Flash |
| LMArena Text: legal and government | 1480 | 1497 | Gemini 3.8 Flash |
| LMArena Text: business and finance | 1439 | 1479 | Gemini 3.8 Flash |
| Neither model has a result on the other 4 boards here | |||
Web designLike-for-likePublic boards, shown as published, kept out of the index06
| Benchmark | Gemini 2.5 Pro | Gemini 3.8 Flash | Leader |
|---|---|---|---|
| Design Arena: websites | 1167 | 1301 | Gemini 3.8 Flash |
| Design Arena: UI components | 1139 | 1318 | Gemini 3.8 Flash |
| Design Arena: game dev | 1112 | 1305 | Gemini 3.8 Flash |
| Design Arena: data viz | 1222 | 1269 | Gemini 3.8 Flash |
| Design Arena: 3D | 1080 | 1295 | Gemini 3.8 Flash |
| Design Arena: all code categories | 1152 | 1304 | Gemini 3.8 Flash |
| Design Arena: SVG | Not measured | 1295 | Only Gemini 3.8 Flash measured |
| Design Arena: ASCII art | Not measured | 1264 | Only Gemini 3.8 Flash measured |
| LiveBench design | Not measured | 72.7% | Only Gemini 3.8 Flash measured |
GeneralLike-for-likePublic boards, shown as published, kept out of the index127
| Benchmark | Gemini 2.5 Pro | Gemini 3.8 Flash | Leader |
|---|---|---|---|
| Vals Index | Not measured | 56.0% | Only Gemini 3.8 Flash measured |
| LiveBench data analysis | Not measured | 54.0% | Only Gemini 3.8 Flash measured |
| Public Benefits Bench (Vals AI) | Not measured | 65.3% | Only Gemini 3.8 Flash measured |
| SAGE (Vals AI) | 41.9% | 35.1% | Gemini 2.5 Pro |
| MedScribe (Vals AI) | 73.5% | 84.5% | Gemini 3.8 Flash |
| IFBench | 48.7% | Not measured | Only Gemini 2.5 Pro measured |
| Long context reasoning (AA-LCR) | 69.0% | 84.0% | Gemini 3.8 Flash |
| DTBench | 82.4% | 95.7% | Gemini 3.8 Flash |
| LMCA | 34.8% | 52.9% | Gemini 3.8 Flash |
| Creative writing (Lech Mazur) | 83.8% | Not measured | Only Gemini 2.5 Pro measured |
| Surface Evolver Bench | Not measured | 76.9% | Only Gemini 3.8 Flash measured |
| Furniture assembly | Not measured | 31.7% | Only Gemini 3.8 Flash measured |
| LMArena Text | 1458 | 1499 | Gemini 3.8 Flash |
| LMArena Text: instruction following | 1437 | 1492 | Gemini 3.8 Flash |
| LMArena Text: creative writing | 1454 | 1488 | Gemini 3.8 Flash |
| LMArena Vision | 1263 | 1315 | Gemini 3.8 Flash |
| LMArena Text: English | 1458 | 1498 | Gemini 3.8 Flash |
| LMArena Text: non-English | 1452 | 1491 | Gemini 3.8 Flash |
| LMArena Text: Chinese | 1507 | 1553 | Gemini 3.8 Flash |
| LMArena Text: German | 1487 | 1501 | Gemini 3.8 Flash |
| LMArena Text: Japanese | 1461 | 1507 | Gemini 3.8 Flash |
| LMArena Text: Korean | 1434 | 1464 | Gemini 3.8 Flash |
| LMArena Text: French | 1473 | 1496 | Gemini 3.8 Flash |
| LMArena Text: Spanish | 1474 | 1487 | Gemini 3.8 Flash |
| LMArena Text: Russian | 1461 | 1514 | Gemini 3.8 Flash |
| LMArena Text: Polish | 1479 | 1497 | Gemini 3.8 Flash |
| LMArena Text: multi-turn | 1453 | 1503 | Gemini 3.8 Flash |
| LMArena Text: longer queries | 1449 | 1507 | Gemini 3.8 Flash |
| LMArena Text: writing and language | 1454 | 1494 | Gemini 3.8 Flash |
| LMArena Text: entertainment and media | 1441 | 1480 | Gemini 3.8 Flash |
| LMArena Vision: English | 1261 | 1318 | Gemini 3.8 Flash |
| LMArena Vision: Chinese | 1300 | 1416 | Gemini 3.8 Flash |
| LMArena Vision: reading text | 1270 | 1333 | Gemini 3.8 Flash |
| LMArena Vision: humor | 1262 | 1321 | Gemini 3.8 Flash |
| LMArena Vision: captioning | 1304 | Not measured | Only Gemini 2.5 Pro measured |
| LMArena Vision: recognizing things | 1283 | Not measured | Only Gemini 2.5 Pro measured |
| LMArena Vision: creative writing | 1265 | 1299 | Gemini 3.8 Flash |
| LMArena Document | 1421 | Not measured | Only Gemini 2.5 Pro measured |
| 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 2.5 Pro | Gemini 3.8 Flash | 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 2.5 Pro$0.0063Fits in one request
Gemini 3.8 Flash$0.0029Fits in one request
Gemini 3.8 Flash costs less
Repository review
50K input + 3K output tokens
Gemini 2.5 Pro$0.092Fits in one request
Gemini 3.8 Flash$0.054Fits in one request
Gemini 3.8 Flash costs less
Agent loop
200K input + 10K output tokens
Gemini 2.5 Pro$0.350Fits in one request
Gemini 3.8 Flash$0.206Fits in one request
Gemini 3.8 Flash 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 2.5 Pro | Google Gemini 3.8 Flash |
|---|---|---|
| Maker | ||
| Weights | No public weights listed | No public weights listed |
| Released | June 17, 2025 | September 2, 2026 |
| Context window | 1.05M | 1.05M |
| Input $/Mtok | $1.25 | $0.825 |
| Output $/Mtok | $10.00 | $4.125 |
| Coding index | 37.0 | 70.5 |
| Independent measurements behind it | 2 | 2 |
| Cost per solved task | $0.64 | $2.74 |
| Source | OpenRouter listing | OpenRouter listing |
Questions
Is Gemini 2.5 Pro better than Gemini 3.8 Flash for coding?
Pick Gemini 3.8 Flash for coding: it scores 70.5 on the Vibe Coding Index against 37.0 for Gemini 2.5 Pro. Pick Gemini 2.5 Pro when a solved task costs $0.64 against $2.74, or when what matters is MortgageTax (Vals AI) or MedCode (Vals AI), where it leads.
Which is cheaper, Gemini 2.5 Pro or Gemini 3.8 Flash?
Gemini 2.5 Pro costs $1.25 per million input tokens and $10.00 per million output tokens; Gemini 3.8 Flash costs $0.825 and $4.125. Per solved SWE-bench Verified task, Gemini 2.5 Pro costs $0.64 and Gemini 3.8 Flash $2.74.
Which has the bigger context window, Gemini 2.5 Pro or Gemini 3.8 Flash?
Neither: both take 1.05M tokens.
How many benchmarks is the Gemini 2.5 Pro vs Gemini 3.8 Flash comparison based on?
69 benchmarks have a result for both models as of October 21, 2026. Gemini 2.5 Pro's coding index rests on 2 independent benchmarks and Gemini 3.8 Flash's on 2. Where only one model has a result, the page says so instead of naming a winner.