Claude Opus 4.1 vs Gemini 2.5 Flash
Updated October 21, 2026. 44 benchmarks have a result for both. Coding is ranked on the Vibe Coding Index; every other board is shown as published.
Decision reading
Claude Opus 4.1 and Gemini 2.5 Flash are level for coding, 27.2 against 28.7 on the Vibe Coding Index, so price and context decide.
Pick Claude Opus 4.1 when what matters is Terminal-Bench or LMArena Text: coding, where it leads. Pick Gemini 2.5 Flash when output tokens cost 30.0x less, or when the context window is larger, 1.05M against 200K tokens.
- Shared results
- 44
- Claude Opus 4.1 only
- 27
- Gemini 2.5 Flash only
- 25
- Like-for-like categories
- 7 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
No call
Level: 27.2 against 28.7, inside 2 points.
One benchmark behind each score
Intelligence
AA Intelligence Index
Claude Opus 4.1
Claude Opus 4.1 leads, 22.8 against 15.5.
Same board, both measured
Reasoning
GPQA Diamond
No call
Only Claude Opus 4.1 has a GPQA Diamond result, 76.3%.
Directional only
Math
AIME
No call
Only Claude Opus 4.1 has a AIME result, 78.2%.
Directional only
Knowledge
MMLU Pro
No call
Only Claude Opus 4.1 has a MMLU Pro result, 87.9%.
Directional only
Web design
Design Arena: websites
Claude Opus 4.1
Claude Opus 4.1 leads, 1177 against 1074.
Same board, both measured
Long documents
Listed context window
Gemini 2.5 Flash
Gemini 2.5 Flash takes 1.05M tokens against 200K.
Listed by OpenRouter
Everyday cost
1K input + 500 output tokens
Gemini 2.5 Flash
Claude Opus 4.1 $0.052, Gemini 2.5 Flash $0.0015 per turn.
List prices
Cost per solved task
One SWE-bench Verified task, solved
No call
Only Gemini 2.5 Flash has the number, $0.466.
Directional only
At a glance
- Coding index
- Claude Opus 4.1 27.2 from 1 benchmark, Gemini 2.5 Flash 28.7 from 1 benchmark.
- Widest category
- Web design, 16.3 points apart on average over 7 shared benchmarks.
- Widest single gap
- Terminal-Bench: Claude Opus 4.1 38.0% against Gemini 2.5 Flash 17.1%, 20.9 points apart on a 0 to 100 scale.
- Output price
- Claude Opus 4.1 $75.00 against Gemini 2.5 Flash $2.50 per million output tokens, 30.0x apart.
- Context window
- Claude Opus 4.1 takes 200K tokens, Gemini 2.5 Flash 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 4.1 | Bars | Gemini 2.5 Flash | Ties |
|---|---|---|---|---|
| Coding | 3 | 0 | ||
| Intelligence | 2 | 0 | ||
| Reasoning | 4 | 0 | ||
| Math | 2 | 0 | ||
| Knowledge | 2 | 3 | ||
| Web design | 7 | 0 | ||
| General | 13 | 8 | ||
| All shared boards | 33 | 11 |
CodingLike-for-likeFour of these boards feed the Vibe Coding Index30
| Benchmark | Claude Opus 4.1 | Gemini 2.5 Flash | Leader |
|---|---|---|---|
| SWE-bench Verified | Not measured | 28.7% | Only Gemini 2.5 Flash measured |
| LMArena WebDev | 1390 | Not measured | Only Claude Opus 4.1 measured |
| LiveCodeBench (Vals AI) | 66.5% | Not measured | Only Claude Opus 4.1 measured |
| LiveCodeBench (Artificial Analysis run) | Not measured | 69.5% | Only Gemini 2.5 Flash measured |
| Terminal-Bench Hard (Artificial Analysis run) | Not measured | 13.6% | Only Gemini 2.5 Flash measured |
| Terminal-Bench | 38.0% | 17.1% | Claude Opus 4.1 |
| WeirdML | 45.9% | Not measured | Only Claude Opus 4.1 measured |
| Cybench | 42.0% | Not measured | Only Claude Opus 4.1 measured |
| LMArena Text: coding | 1479 | 1423 | Claude Opus 4.1 |
| LMArena Text: software and IT | 1456 | 1425 | Claude Opus 4.1 |
| LMArena WebDev: HTML | 1399 | Not measured | Only Claude Opus 4.1 measured |
| Neither model has a result on the other 27 boards here | |||
IntelligenceLike-for-likePublic boards, shown as published, kept out of the index20
| Benchmark | Claude Opus 4.1 | Gemini 2.5 Flash | Leader |
|---|---|---|---|
| AA Intelligence Index | 22.8 | 15.5 | Claude Opus 4.1 |
| Epoch Capabilities Index | 144.1 | 142.9 | Claude Opus 4.1 |
Agentic workDirectional onlyPublic boards, shown as published, kept out of the index6 boards, none shared
| Benchmark | Claude Opus 4.1 | Gemini 2.5 Flash | Leader |
|---|---|---|---|
| τ²-Bench Telecom | Not measured | 31.6% | Only Gemini 2.5 Flash measured |
| METR time horizons | 66.8% | Not measured | Only Claude Opus 4.1 measured |
| GDPval | 43.6% | Not measured | Only Claude Opus 4.1 measured |
| BALROG | Not measured | 33.5% | Only Gemini 2.5 Flash measured |
| DeepResearch Bench | 48.3% | Not measured | Only Claude Opus 4.1 measured |
| Vending-Bench 2 | Not measured | $549 | Only Gemini 2.5 Flash measured |
| Neither model has a result on the other 33 boards here | |||
ReasoningLike-for-likePublic boards, shown as published, kept out of the index40
| Benchmark | Claude Opus 4.1 | Gemini 2.5 Flash | Leader |
|---|---|---|---|
| GPQA Diamond | 76.3% | Not measured | Only Claude Opus 4.1 measured |
| MMMU Pro (Vals AI) | 77.5% | Not measured | Only Claude Opus 4.1 measured |
| GPQA Diamond (Artificial Analysis run) | Not measured | 79.0% | Only Gemini 2.5 Flash measured |
| Humanity's Last Exam (Artificial Analysis run) | Not measured | 12.1% | Only Gemini 2.5 Flash measured |
| GPQA Diamond (Epoch AI run) | 77.3% | Not measured | Only Claude Opus 4.1 measured |
| ARC-AGI | Not measured | 33.3% | Only Gemini 2.5 Flash measured |
| ARC-AGI-2 | Not measured | 2.5% | Only Gemini 2.5 Flash measured |
| SimpleBench | 60.0% | 41.2% | Claude Opus 4.1 |
| Mystery game puzzles | 21.0% | Not measured | Only Claude Opus 4.1 measured |
| EBR-bench | 7.9% | Not measured | Only Claude Opus 4.1 measured |
| VPCT | 35.0% | Not measured | Only Claude Opus 4.1 measured |
| LMArena Text: hard prompts | 1442 | 1422 | Claude Opus 4.1 |
| LMArena Text: expert | 1438 | 1426 | Claude Opus 4.1 |
| LMArena Text: hard prompts in English | 1451 | 1420 | Claude Opus 4.1 |
| LMArena Vision: diagrams | Not measured | 1245 | Only Gemini 2.5 Flash measured |
| LMArena Vision: homework | Not measured | 1244 | Only Gemini 2.5 Flash measured |
| Neither model has a result on the other 5 boards here | |||
MathLike-for-likePublic boards, shown as published, kept out of the index20
| Benchmark | Claude Opus 4.1 | Gemini 2.5 Flash | Leader |
|---|---|---|---|
| AIME | 78.2% | Not measured | Only Claude Opus 4.1 measured |
| MATH 500 (Vals AI) | 95.4% | Not measured | Only Claude Opus 4.1 measured |
| MGSM (Vals AI) | 94.4% | Not measured | Only Claude Opus 4.1 measured |
| AA Math Index | Not measured | 73.3 | Only Gemini 2.5 Flash measured |
| AIME 2025 (Artificial Analysis run) | Not measured | 73.3% | Only Gemini 2.5 Flash measured |
| OTIS Mock AIME | 68.9% | Not measured | Only Claude Opus 4.1 measured |
| FrontierMath, tiers 1 to 3 | 12.6% | Not measured | Only Claude Opus 4.1 measured |
| FrontierMath, tier 4 | 2.4% | Not measured | Only Claude Opus 4.1 measured |
| LMArena Text: math | 1431 | 1411 | Claude Opus 4.1 |
| LMArena Text: mathematical work | 1434 | 1422 | Claude Opus 4.1 |
| Neither model has a result on the other 3 boards here | |||
KnowledgeLike-for-likePublic boards, shown as published, kept out of the index23
| Benchmark | Claude Opus 4.1 | Gemini 2.5 Flash | Leader |
|---|---|---|---|
| MMLU Pro | 87.9% | Not measured | Only Claude Opus 4.1 measured |
| LegalBench (Vals AI) | 83.5% | Not measured | Only Claude Opus 4.1 measured |
| TaxEval (Vals AI) | 73.7% | Not measured | Only Claude Opus 4.1 measured |
| MortgageTax (Vals AI) | 61.1% | Not measured | Only Claude Opus 4.1 measured |
| MedQA (Vals AI) | 93.6% | Not measured | Only Claude Opus 4.1 measured |
| MedCode (Vals AI) | 47.2% | 40.4% | Claude Opus 4.1 |
| MMLU Pro (Artificial Analysis run) | Not measured | 83.2% | Only Gemini 2.5 Flash measured |
| LMArena Text: science | 1422 | 1433 | Gemini 2.5 Flash |
| LMArena Text: medicine and healthcare | 1416 | 1428 | Gemini 2.5 Flash |
| LMArena Text: legal and government | 1421 | 1430 | Gemini 2.5 Flash |
| LMArena Text: business and finance | 1406 | 1404 | Claude Opus 4.1 |
| Neither model has a result on the other 6 boards here | |||
Web designLike-for-likePublic boards, shown as published, kept out of the index70
| Benchmark | Claude Opus 4.1 | Gemini 2.5 Flash | Leader |
|---|---|---|---|
| Design Arena: websites | 1177 | 1074 | Claude Opus 4.1 |
| Design Arena: UI components | 1164 | 1005 | Claude Opus 4.1 |
| Design Arena: game dev | 1172 | 1005 | Claude Opus 4.1 |
| Design Arena: data viz | 1166 | 1060 | Claude Opus 4.1 |
| Design Arena: 3D | 1153 | 1021 | Claude Opus 4.1 |
| Design Arena: all code categories | 1171 | 1059 | Claude Opus 4.1 |
| Design Arena: SVG | 1152 | 1018 | Claude Opus 4.1 |
| Design Arena: ASCII art | 1167 | Not measured | Only Claude Opus 4.1 measured |
| Neither model has a result on the other 1 board here | |||
GeneralLike-for-likePublic boards, shown as published, kept out of the index138
| Benchmark | Claude Opus 4.1 | Gemini 2.5 Flash | Leader |
|---|---|---|---|
| SAGE (Vals AI) | 31.4% | 44.8% | Gemini 2.5 Flash |
| MedScribe (Vals AI) | 73.9% | 83.0% | Gemini 2.5 Flash |
| IFBench | Not measured | 50.3% | Only Gemini 2.5 Flash measured |
| Long context reasoning (AA-LCR) | Not measured | 65.3% | Only Gemini 2.5 Flash measured |
| DTBench | 80.0% | 76.5% | Claude Opus 4.1 |
| LMCA | 37.1% | 27.5% | Claude Opus 4.1 |
| Creative writing (Lech Mazur) | 84.7% | Not measured | Only Claude Opus 4.1 measured |
| LMArena Text | 1419 | 1417 | Claude Opus 4.1 |
| LMArena Text: instruction following | 1435 | 1405 | Claude Opus 4.1 |
| LMArena Text: creative writing | 1412 | 1400 | Claude Opus 4.1 |
| LMArena Vision | Not measured | 1235 | Only Gemini 2.5 Flash measured |
| LMArena Text: English | 1433 | 1418 | Claude Opus 4.1 |
| LMArena Text: non-English | 1405 | 1409 | Gemini 2.5 Flash |
| LMArena Text: Chinese | 1427 | 1449 | Gemini 2.5 Flash |
| LMArena Text: German | 1413 | 1417 | Gemini 2.5 Flash |
| LMArena Text: Japanese | 1377 | 1396 | Gemini 2.5 Flash |
| LMArena Text: Korean | 1381 | 1385 | Gemini 2.5 Flash |
| LMArena Text: French | 1433 | 1432 | Claude Opus 4.1 |
| LMArena Text: Spanish | 1448 | 1422 | Claude Opus 4.1 |
| LMArena Text: Russian | 1422 | 1415 | Claude Opus 4.1 |
| LMArena Text: Polish | 1413 | 1413 | Gemini 2.5 Flash |
| LMArena Text: multi-turn | 1444 | 1408 | Claude Opus 4.1 |
| LMArena Text: longer queries | 1455 | 1419 | Claude Opus 4.1 |
| LMArena Text: writing and language | 1418 | 1405 | Claude Opus 4.1 |
| LMArena Text: entertainment and media | 1398 | 1393 | Claude Opus 4.1 |
| LMArena Vision: English | Not measured | 1239 | Only Gemini 2.5 Flash measured |
| LMArena Vision: Chinese | Not measured | 1284 | Only Gemini 2.5 Flash measured |
| LMArena Vision: reading text | Not measured | 1237 | Only Gemini 2.5 Flash measured |
| LMArena Vision: humor | Not measured | 1225 | Only Gemini 2.5 Flash measured |
| LMArena Vision: captioning | Not measured | 1277 | Only Gemini 2.5 Flash measured |
| LMArena Vision: recognizing things | Not measured | 1252 | Only Gemini 2.5 Flash measured |
| LMArena Vision: creative writing | Not measured | 1241 | Only Gemini 2.5 Flash measured |
| Neither model has a result on the other 14 boards here | |||
Image generationNot comparablePublic boards, shown as published, kept out of the index0 boards, none shared
| Benchmark | Claude Opus 4.1 | Gemini 2.5 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 Flash costs less
Repository review
50K input + 3K output tokens
Gemini 2.5 Flash costs less
Agent loop
200K input + 10K output tokens
Gemini 2.5 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 | Anthropic Claude Opus 4.1 | Google Gemini 2.5 Flash |
|---|---|---|
| Maker | Anthropic | |
| Weights | No public weights listed | No public weights listed |
| Released | August 5, 2025 | June 17, 2025 |
| Context window | 200K | 1.05M |
| Input $/Mtok | $15.00 | $0.30 |
| Output $/Mtok | $75.00 | $2.50 |
| Coding index | 27.2 | 28.7 |
| Independent measurements behind it | 1 | 1 |
| Cost per solved task | Not computable | $0.466 |
| Source | OpenRouter listing | OpenRouter listing |
Questions
Is Claude Opus 4.1 better than Gemini 2.5 Flash for coding?
Claude Opus 4.1 and Gemini 2.5 Flash are level for coding, 27.2 against 28.7 on the Vibe Coding Index, so price and context decide. Pick Claude Opus 4.1 when what matters is Terminal-Bench or LMArena Text: coding, where it leads. Pick Gemini 2.5 Flash when output tokens cost 30.0x less, or when the context window is larger, 1.05M against 200K tokens.
Which is cheaper, Claude Opus 4.1 or Gemini 2.5 Flash?
Claude Opus 4.1 costs $15.00 per million input tokens and $75.00 per million output tokens; Gemini 2.5 Flash costs $0.30 and $2.50. Cost per solved task is known for Gemini 2.5 Flash only.
Which has the bigger context window, Claude Opus 4.1 or Gemini 2.5 Flash?
Gemini 2.5 Flash, with 1.05M tokens against 200K.
How many benchmarks is the Claude Opus 4.1 vs Gemini 2.5 Flash comparison based on?
44 benchmarks have a result for both models as of October 21, 2026. Claude Opus 4.1's coding index rests on 1 independent benchmark and Gemini 2.5 Flash's on 1. Where only one model has a result, the page says so instead of naming a winner.