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Step 5 PreviewClaude Opus 5 vs Gemini 3.5 Flash
- Claude Opus 5 rates higher on LMArena’s text leaderboard: 1508 against 1482.
- Gemini 3.5 Flash is cheaper: $1.50 / $9 per million input / output tokens, against $5 / $25 for Claude Opus 5.
- On the 11 Vals AI benchmarks both have taken, Claude Opus 5 wins 11 and Gemini 3.5 Flash wins 0.
LatestGemini 3.5 Flash 1482
Side by side
Models (2/6)
- Claude Opus 5
- Gemini 3.5 Flash
| Benchmark | Claude Opus 5 | Gemini 3.5 Flash |
|---|---|---|
| The model | ||
| Lab | Anthropic | |
| Released | 2026-07-24 | 2026-05-19 |
| Weights | Proprietary | Proprietary |
| Context window | 1M | 1M |
| Input, per 1M tokens | $5 | $1.50 |
| Output, per 1M tokens | $25 | $9 |
| LMArena, people’s votes | ||
| LMArena TextMillions of people compare two anonymous models side by side and vote for the better answer | 1508#4 of 351 | 1482#18 of 351 |
| LMArena WebDevPeople ask two anonymous models to build the same web app, try both and vote for the better one | 1691#9 of 124 | 1499#63 of 124 |
| LMArena VisionSide-by-side votes on prompts that include an image | 1320#3 of 146 | 1308#13 of 146 |
| LMArena CodingLMArena’s text votes on prompts that ask for code | 1533#4 of 346 | 1493#33 of 346 |
| LMArena MathLMArena’s text votes on math prompts | 1533#2 of 339 | 1504#12 of 339 |
| LMArena Creative writingLMArena’s text votes on stories, poems and other creative writing | 1495#5 of 349 | 1470#17 of 349 |
| LMArena Hard promptsLMArena’s text votes on the hardest prompts | 1527#4 of 351 | 1488#23 of 351 |
| LMArena Instruction followingLMArena’s text votes on prompts with specific instructions to follow | 1518#5 of 351 | 1467#33 of 351 |
| Vals AI, coding | ||
| Terminal-Bench 4.0Frontier-difficulty tasks an agent completes in a real terminal | 53.53%#9 of 55 | 6.06%#45 of 55 |
| SWE-benchReal GitHub issues from open-source projects | 97.00%#1 of 85 | 78.80%#27 of 85 |
| Vibe Code BenchBuilding complete web apps from a plain-language brief, graded on whether the app works | 88.40%#9 of 115 | 48.68%#60 of 115 |
| LiveCodeBenchFresh competitive programming problems, collected after models’ training cut-offs to avoid contamination | 89.03%#4 of 143 | 87.60%#12 of 143 |
| Vals AI, finance | ||
| Tax Agent BenchAgentic research into US corporate tax questions | 45.55%#4 of 76 | 21.65%#47 of 76 |
| Vals AI, law | ||
| Legal Research BenchAgentic US legal research | 55.29%#2 of 85 | 30.77%#49 of 85 |
| Vals AI, medicine | ||
| MedCodeAssigning the right medical billing codes from clinical notes | 63.57%#1 of 107 | 55.83%#6 of 107 |
| Vals AI, reasoning | ||
| GPQA DiamondGraduate-level questions in biology, physics and chemistry that experts answer well and search does not | 93.43%#8 of 138 | 92.68%#14 of 138 |
| MMLU-ProHarder, reasoning-focused multiple choice across 14 subjects, from law to engineering | 91.59%#2 of 138 | 89.52%#10 of 138 |
| MMMUCollege-level questions that need both an image and text | 89.88%#2 of 93 | 88.27%#8 of 93 |
| Terminal-Bench ScienceExpert-written scientific research workflows, run by an agent in a terminal | 27.14%#9 of 42 | 5.71%#21 of 42 |
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Questions
Which is better, Claude Opus 5 or Gemini 3.5 Flash?
Claude Opus 5 rates higher on LMArena’s text leaderboard: 1508 against 1482. Gemini 3.5 Flash is cheaper: $1.50 / $9 per million input / output tokens, against $5 / $25 for Claude Opus 5. On the 11 Vals AI benchmarks both have taken, Claude Opus 5 wins 11 and Gemini 3.5 Flash wins 0.
Which is cheaper, Claude Opus 5 or Gemini 3.5 Flash?
Gemini 3.5 Flash is cheaper: $1.50 / $9 per million input / output tokens, against $5 / $25 for Claude Opus 5.