Claude Opus 4.5 vs Gemini 3 Flash Preview
Updated October 21, 2026. 58 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 66.8 for Claude Opus 4.5, though on 1 benchmark against 2.
Pick Claude Opus 4.5 when what matters is SWE-bench Verified or SWE-bench Verified (Vals AI), where it leads.
- Shared results
- 58
- Claude Opus 4.5 only
- 47
- Gemini 3 Flash Preview only
- 11
- 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 66.8.
2 and 1 benchmarks behind the scores
Intelligence
AA Intelligence Index
Claude Opus 4.5
Claude Opus 4.5 leads, 29.1 against 26.3.
Same board, both measured
Reasoning
GPQA Diamond
Gemini 3 Flash Preview
Gemini 3 Flash Preview leads, 87.9% against 85.9%.
Same board, both measured
Math
AIME
Gemini 3 Flash Preview
Gemini 3 Flash Preview leads, 95.6% against 95.4%.
Same board, both measured
Knowledge
MMLU Pro
Gemini 3 Flash Preview
Gemini 3 Flash Preview leads, 88.6% against 87.3%.
Same board, both measured
Web design
Design Arena: websites
Claude Opus 4.5
Claude Opus 4.5 leads, 1247 against 1196.
Same board, both measured
Long documents
Listed context window
Gemini 3 Flash Preview
Gemini 3 Flash Preview takes 1.05M tokens against 200K.
Listed by OpenRouter
Everyday cost
1K input + 500 output tokens
Gemini 3 Flash Preview
Claude Opus 4.5 $0.018, Gemini 3 Flash Preview $0.0020 per turn.
List prices
Cost per solved task
One SWE-bench Verified task, solved
Gemini 3 Flash Preview
Claude Opus 4.5 $1.37, Gemini 3 Flash Preview $0.37.
Published attempt cost and pass rate
At a glance
- Coding index
- Claude Opus 4.5 66.8 from 2 benchmarks, Gemini 3 Flash Preview 75.8 from 1 benchmark.
- Widest category
- Math, 9.1 points apart on average over 8 shared benchmarks.
- Widest single gap
- VPCT: Claude Opus 4.5 40.0% against Gemini 3 Flash Preview 72.6%, 32.6 points apart on a 0 to 100 scale.
- Output price
- Claude Opus 4.5 $25.00 against Gemini 3 Flash Preview $3.00 per million output tokens, 8.3x apart.
- Context window
- Claude Opus 4.5 takes 200K tokens, Gemini 3 Flash Preview 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.
| Category | Claude Opus 4.5 | Bars | Gemini 3 Flash Preview | Ties |
|---|---|---|---|---|
| Coding | 6 | 3 | ||
| Intelligence | 1 | 0 | ||
| Agentic work | 7 | 1 | ||
| Reasoning | 2 | 9 | ||
| Math | 2 | 6 | ||
| Knowledge | 4 | 7 | ||
| Web design | 4 | 0 | ||
| General | 4 | 2 | ||
| All shared boards | 30 | 28 |
CodingLike-for-likeFour of these boards feed the Vibe Coding Index63
| Benchmark | Claude Opus 4.5 | Gemini 3 Flash Preview | Leader |
|---|---|---|---|
| SWE-bench Verified | 79.2% | 75.8% | Claude Opus 4.5 |
| SWE-bench (full test set) | 52.6% | Not measured | Only Claude Opus 4.5 measured |
| SWE-bench Multilingual | 70.7% | Not measured | Only Claude Opus 4.5 measured |
| LMArena WebDev | 1494 | Not measured | Only Claude Opus 4.5 measured |
| LiveCodeBench (Vals AI) | 83.7% | 85.6% | Gemini 3 Flash Preview |
| SWE-bench Verified (Vals AI) | 76.4% | 75.0% | Claude Opus 4.5 |
| Vibe Code Bench (Vals AI) | 20.6% | 20.2% | Claude Opus 4.5 |
| Code migration (Vals AI) | Not measured | 6.4% | Only Gemini 3 Flash Preview measured |
| ProgramBench (Vals AI) | Not measured | 0.0% | Only Gemini 3 Flash Preview measured |
| Terminal-Bench 2.1 (Vals AI) | Not measured | 53.9% | Only Gemini 3 Flash Preview measured |
| LiveCodeBench (Artificial Analysis run) | 87.1% | 90.8% | Gemini 3 Flash Preview |
| Terminal-Bench Hard (Artificial Analysis run) | 47.0% | 38.6% | Claude Opus 4.5 |
| Terminal-Bench | 63.1% | 64.3% | Gemini 3 Flash Preview |
| GSO-Bench | 26.5% | 9.8% | Claude Opus 4.5 |
| WeirdML | 63.7% | 61.6% | Claude Opus 4.5 |
| Cybench | 82.0% | Not measured | Only Claude Opus 4.5 measured |
| ALE-Bench | Not measured | 1367.2 | Only Gemini 3 Flash Preview measured |
| LMArena Text: coding | 1503 | Not measured | Only Claude Opus 4.5 measured |
| LMArena Text: software and IT | 1483 | Not measured | Only Claude Opus 4.5 measured |
| LMArena WebDev: React | 1478 | Not measured | Only Claude Opus 4.5 measured |
| LMArena WebDev: HTML | 1510 | Not measured | Only Claude Opus 4.5 measured |
| Neither model has a result on the other 17 boards here | |||
IntelligenceLike-for-likePublic boards, shown as published, kept out of the index10
| Benchmark | Claude Opus 4.5 | Gemini 3 Flash Preview | Leader |
|---|---|---|---|
| AA Intelligence Index | 29.1 | 26.3 | Claude Opus 4.5 |
| Epoch Capabilities Index | 150.1 | Not measured | Only Claude Opus 4.5 measured |
Agentic workLike-for-likePublic boards, shown as published, kept out of the index71
| Benchmark | Claude Opus 4.5 | Gemini 3 Flash Preview | Leader |
|---|---|---|---|
| Design Arena: agents building web apps | 1159 | 1111 | Claude Opus 4.5 |
| Design Arena: agents building full-stack apps | 1156 | 1063 | Claude Opus 4.5 |
| Design Arena: agents building mobile apps | 1189 | 1090 | Claude Opus 4.5 |
| Design Arena: agents building Android apps | 1181 | 1056 | Claude Opus 4.5 |
| Design Arena: agents building Godot games | Not measured | 1161 | Only Gemini 3 Flash Preview measured |
| Design Arena: PowerPoint slides | Not measured | 1036 | Only Gemini 3 Flash Preview measured |
| Finance Agent (Vals AI) | Not measured | 42.5% | Only Gemini 3 Flash Preview measured |
| Tax Agent Bench (Vals AI) | Not measured | 11.8% | Only Gemini 3 Flash Preview measured |
| Legal Research Bench (Vals AI) | Not measured | 18.3% | Only Gemini 3 Flash Preview measured |
| Excel Modeling Benchmark (Vals AI) | Not measured | 26.0% | Only Gemini 3 Flash Preview measured |
| τ²-Bench Telecom | 89.5% | 80.4% | Claude Opus 4.5 |
| METR time horizons | 75.0% | Not measured | Only Claude Opus 4.5 measured |
| Remote Labor Index | 3.8% | Not measured | Only Claude Opus 4.5 measured |
| GDPval | 45.5% | Not measured | Only Claude Opus 4.5 measured |
| BALROG | 43.5% | 48.1% | Gemini 3 Flash Preview |
| DeepResearch Bench | 54.8% | 49.8% | Claude Opus 4.5 |
| OSWorld | 66.3% | Not measured | Only Claude Opus 4.5 measured |
| Vending-Bench 2 | $4,967 | $3,635 | Claude Opus 4.5 |
| Neither model has a result on the other 21 boards here | |||
ReasoningLike-for-likePublic boards, shown as published, kept out of the index29
| Benchmark | Claude Opus 4.5 | Gemini 3 Flash Preview | Leader |
|---|---|---|---|
| GPQA Diamond | 85.9% | 87.9% | Gemini 3 Flash Preview |
| MMMU Pro (Vals AI) | 83.0% | 87.6% | Gemini 3 Flash Preview |
| GPQA Diamond (Artificial Analysis run) | 86.6% | 89.8% | Gemini 3 Flash Preview |
| Humanity's Last Exam (Artificial Analysis run) | 30.1% | 36.6% | Gemini 3 Flash Preview |
| GPQA Diamond (Epoch AI run) | 86.0% | 89.4% | Gemini 3 Flash Preview |
| ARC-AGI | 80.0% | 84.7% | Gemini 3 Flash Preview |
| ARC-AGI-2 | 37.6% | 33.6% | Claude Opus 4.5 |
| SimpleBench | 62.0% | 61.1% | Claude Opus 4.5 |
| Chess puzzles | 14.0% | 39.0% | Gemini 3 Flash Preview |
| Mystery game puzzles | 22.0% | 26.0% | Gemini 3 Flash Preview |
| EBR-bench | 14.3% | Not measured | Only Claude Opus 4.5 measured |
| VPCT | 40.0% | 72.6% | Gemini 3 Flash Preview |
| LMArena Text: hard prompts | 1476 | Not measured | Only Claude Opus 4.5 measured |
| LMArena Text: expert | 1487 | Not measured | Only Claude Opus 4.5 measured |
| LMArena Text: hard prompts in English | 1482 | Not measured | Only Claude Opus 4.5 measured |
| Neither model has a result on the other 6 boards here | |||
MathLike-for-likePublic boards, shown as published, kept out of the index26
| Benchmark | Claude Opus 4.5 | Gemini 3 Flash Preview | Leader |
|---|---|---|---|
| AIME | 95.4% | 95.6% | Gemini 3 Flash Preview |
| MGSM (Vals AI) | 95.2% | 93.3% | Claude Opus 4.5 |
| AA Math Index | 91.3 | 97.0 | Gemini 3 Flash Preview |
| AIME 2025 (Artificial Analysis run) | 91.3% | 97.0% | Gemini 3 Flash Preview |
| OTIS Mock AIME | 86.1% | 95.6% | Gemini 3 Flash Preview |
| FrontierMath, tiers 1 to 3 | 34.4% | 51.2% | Gemini 3 Flash Preview |
| FrontierMath, tier 4 | 4.9% | 17.1% | Gemini 3 Flash Preview |
| ProofBench | 36.0% | 15.0% | Claude Opus 4.5 |
| LMArena Text: math | 1463 | Not measured | Only Claude Opus 4.5 measured |
| LMArena Text: mathematical work | 1468 | Not measured | Only Claude Opus 4.5 measured |
| Neither model has a result on the other 3 boards here | |||
KnowledgeLike-for-likePublic boards, shown as published, kept out of the index47
| Benchmark | Claude Opus 4.5 | Gemini 3 Flash Preview | Leader |
|---|---|---|---|
| MMLU Pro | 87.3% | 88.6% | Gemini 3 Flash Preview |
| LegalBench (Vals AI) | 84.6% | 86.9% | Gemini 3 Flash Preview |
| CaseLaw (Vals AI) | 62.6% | 55.8% | Claude Opus 4.5 |
| CorpFin (Vals AI) | 65.1% | 66.4% | Gemini 3 Flash Preview |
| TaxEval (Vals AI) | 74.9% | 73.9% | Claude Opus 4.5 |
| MortgageTax (Vals AI) | 68.7% | 68.7% | Gemini 3 Flash Preview |
| MedQA (Vals AI) | 95.9% | 95.8% | Claude Opus 4.5 |
| MedCode (Vals AI) | 49.2% | 55.9% | Gemini 3 Flash Preview |
| MMLU Pro (Artificial Analysis run) | 89.5% | 89.0% | Claude Opus 4.5 |
| SimpleQA Verified | 45.7% | 66.8% | Gemini 3 Flash Preview |
| GeoBench | 75.0% | 88.0% | Gemini 3 Flash Preview |
| LMArena Text: science | 1454 | Not measured | Only Claude Opus 4.5 measured |
| LMArena Text: medicine and healthcare | 1444 | Not measured | Only Claude Opus 4.5 measured |
| LMArena Text: legal and government | 1459 | Not measured | Only Claude Opus 4.5 measured |
| LMArena Text: business and finance | 1448 | Not measured | Only Claude Opus 4.5 measured |
| Neither model has a result on the other 2 boards here | |||
Web designLike-for-likePublic boards, shown as published, kept out of the index40
| Benchmark | Claude Opus 4.5 | Gemini 3 Flash Preview | Leader |
|---|---|---|---|
| Design Arena: websites | 1247 | 1196 | Claude Opus 4.5 |
| Design Arena: UI components | 1238 | Not measured | Only Claude Opus 4.5 measured |
| Design Arena: game dev | 1229 | 1166 | Claude Opus 4.5 |
| Design Arena: data viz | 1243 | Not measured | Only Claude Opus 4.5 measured |
| Design Arena: 3D | 1214 | 1184 | Claude Opus 4.5 |
| Design Arena: all code categories | 1242 | 1189 | Claude Opus 4.5 |
| Design Arena: SVG | 1180 | Not measured | Only Claude Opus 4.5 measured |
| Design Arena: ASCII art | 1190 | Not measured | Only Claude Opus 4.5 measured |
| Neither model has a result on the other 1 board here | |||
GeneralLike-for-likePublic boards, shown as published, kept out of the index42
| Benchmark | Claude Opus 4.5 | Gemini 3 Flash Preview | Leader |
|---|---|---|---|
| SAGE (Vals AI) | 52.1% | 51.8% | Claude Opus 4.5 |
| MedScribe (Vals AI) | 85.3% | 69.9% | Claude Opus 4.5 |
| Vals Multimodal Index | Not measured | 52.2% | Only Gemini 3 Flash Preview measured |
| IFBench | 58.0% | 78.0% | Gemini 3 Flash Preview |
| Long context reasoning (AA-LCR) | 77.3% | 78.0% | Gemini 3 Flash Preview |
| DTBench | 89.9% | 89.1% | Claude Opus 4.5 |
| LMCA | 44.5% | 43.1% | Claude Opus 4.5 |
| CL-bench | 21.1% | Not measured | Only Claude Opus 4.5 measured |
| Furniture assembly | 28.3% | Not measured | Only Claude Opus 4.5 measured |
| LMArena Text | 1451 | Not measured | Only Claude Opus 4.5 measured |
| LMArena Text: instruction following | 1478 | Not measured | Only Claude Opus 4.5 measured |
| LMArena Text: creative writing | 1445 | Not measured | Only Claude Opus 4.5 measured |
| LMArena Text: English | 1461 | Not measured | Only Claude Opus 4.5 measured |
| LMArena Text: non-English | 1438 | Not measured | Only Claude Opus 4.5 measured |
| LMArena Text: Chinese | 1470 | Not measured | Only Claude Opus 4.5 measured |
| LMArena Text: German | 1449 | Not measured | Only Claude Opus 4.5 measured |
| LMArena Text: Japanese | 1417 | Not measured | Only Claude Opus 4.5 measured |
| LMArena Text: Korean | 1424 | Not measured | Only Claude Opus 4.5 measured |
| LMArena Text: French | 1471 | Not measured | Only Claude Opus 4.5 measured |
| LMArena Text: Spanish | 1457 | Not measured | Only Claude Opus 4.5 measured |
| LMArena Text: Russian | 1447 | Not measured | Only Claude Opus 4.5 measured |
| LMArena Text: Polish | 1439 | Not measured | Only Claude Opus 4.5 measured |
| LMArena Text: multi-turn | 1466 | Not measured | Only Claude Opus 4.5 measured |
| LMArena Text: longer queries | 1479 | Not measured | Only Claude Opus 4.5 measured |
| LMArena Text: writing and language | 1452 | Not measured | Only Claude Opus 4.5 measured |
| LMArena Text: entertainment and media | 1434 | Not measured | Only Claude Opus 4.5 measured |
| LMArena Document | 1462 | Not measured | Only Claude Opus 4.5 measured |
| Neither model has a result on the other 19 boards here | |||
Image generationNot comparablePublic boards, shown as published, kept out of the index0 boards, none shared
| Benchmark | Claude Opus 4.5 | Gemini 3 Flash Preview | 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 | Anthropic Claude Opus 4.5 | Google Gemini 3 Flash Preview |
|---|---|---|
| Maker | Anthropic | |
| Weights | No public weights listed | No public weights listed |
| Released | November 24, 2025 | December 17, 2025 |
| Context window | 200K | 1.05M |
| Input $/Mtok | $5.00 | $0.50 |
| Output $/Mtok | $25.00 | $3.00 |
| Coding index | 66.8 | 75.8 |
| Independent measurements behind it | 2 | 1 |
| Cost per solved task | $1.37 | $0.37 |
| Source | OpenRouter listing | OpenRouter listing |
Questions
Is Claude Opus 4.5 better than Gemini 3 Flash Preview for coding?
Pick Gemini 3 Flash Preview for coding: it scores 75.8 on the Vibe Coding Index against 66.8 for Claude Opus 4.5, though on 1 benchmark against 2. Pick Claude Opus 4.5 when what matters is SWE-bench Verified or SWE-bench Verified (Vals AI), where it leads.
Which is cheaper, Claude Opus 4.5 or Gemini 3 Flash Preview?
Claude Opus 4.5 costs $5.00 per million input tokens and $25.00 per million output tokens; Gemini 3 Flash Preview costs $0.50 and $3.00. Per solved SWE-bench Verified task, Claude Opus 4.5 costs $1.37 and Gemini 3 Flash Preview $0.37.
Which has the bigger context window, Claude Opus 4.5 or Gemini 3 Flash Preview?
Gemini 3 Flash Preview, with 1.05M tokens against 200K.
How many benchmarks is the Claude Opus 4.5 vs Gemini 3 Flash Preview comparison based on?
58 benchmarks have a result for both models as of October 21, 2026. Claude Opus 4.5's coding index rests on 2 independent benchmarks and Gemini 3 Flash Preview's on 1. Where only one model has a result, the page says so instead of naming a winner.