Model comparison
Gemini 3.5 Flash vs o3-pro
Gemini 3.5 Flash is the stronger model overall, scoring 54.1 to 42.7 on the Noometry Index.
Last verified . 6 shared benchmarks.
GoogleSummary
- They share 6 benchmarks with published results for both. Gemini 3.5 Flash scores higher in 3 categories and o3-pro in 2 categories; 5 gaps are clear of the uncertainty.
- The widest gap is in reasoning, where Gemini 3.5 Flash leads 62.7 to 24.1.
- The biggest single-benchmark swing is ARC-AGI-2: 72.1% for Gemini 3.5 Flash and 4.9% for o3-pro.
- Gemini 3.5 Flash is cheaper at $1.50 / $9 per million input/output tokens, against $20 / $80 for o3-pro.
- Gemini 3.5 Flash accepts more context: 1.05M tokens versus 200K.
Side by side
| Gemini 3.5 Flash | o3-pro | |
|---|---|---|
| Provider | OpenAI | |
| Noometry Index | 54.1 | 42.7 |
| Released | 2026-05-19 | 2025-06-10 |
| Weights | Proprietary | Proprietary |
| Context window | 1.05M | 200K |
| Max output | 66K | 100K |
| Input $ / M tokens | $1.50 | $20 |
| Output $ / M tokens | $9 | $80 |
| Results tracked | 54 | 12 |
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Category by category
Coding o3-pro leads
Gemini 3.5 Flash: 49.1 (#46), o3-pro: 55.1 (#22)
| Benchmark | Gemini 3.5 Flash | o3-pro |
|---|---|---|
| WeirdML | 62.6% | 58.2% |
| SWE-bench Verified | 79.3% | — |
| DeepSWE | 37.4% | — |
| Aider Polyglot | — | 84.9% |
| LMArena WebDev | 1499 | — |
| SciCode | 53.1% | — |
| LMArena Coding | 1492 | — |
| ALE-Bench | 911.02 | — |
Agentic & Tool Use Not comparable
Gemini 3.5 Flash: 24.8 (#107), o3-pro: —
| Benchmark | Gemini 3.5 Flash | o3-pro |
|---|---|---|
| APEX-Agents | 27.5% | — |
| GBAEval | 6.7% | — |
| GDP.pdf | 14% | — |
| Vending-Bench 2 | 5,396 | — |
Reasoning Gemini 3.5 Flash leads
Gemini 3.5 Flash: 62.7 (#16), o3-pro: 24.1 (#152)
| Benchmark | Gemini 3.5 Flash | o3-pro |
|---|---|---|
| ARC-AGI-2 | 72.1% | 4.9% |
| ARC-AGI-1 | 92.5% | 59.3% |
| DTBench | 94.7% | 86.9% |
| LMCA | 47.1% | 38.5% |
| Epoch Capabilities Index | 154.55 | 147.43 |
| SimpleBench | 76.7% | — |
| Kagi LLM Benchmark | — | 72.1% |
| NYT Connections (extended) | 92.6% | — |
| CritPt | 13.1% | — |
| Chess Puzzles | 50% | — |
| EnigmaEval | 25.4% | — |
| EBR-Bench | 4.8% | — |
| LMArena Hard Prompts | 1488 | — |
| Mystery Game Puzzles | 32% | — |
| Surface Evolver Bench | 58.1% | — |
| ForecastBench | 59 | — |
Math Not comparable
Gemini 3.5 Flash: 60.5 (#30), o3-pro: —
| Benchmark | Gemini 3.5 Flash | o3-pro |
|---|---|---|
| FrontierMath (Tiers 1-3) | 62.8% | — |
| FrontierMath Tier 4 | 26.8% | — |
| MathArena Final-Answer Competitions | 76.3% | — |
| OTIS Mock AIME 2024-2025 | 95.6% | — |
| ProofBench | 31% | — |
| LMArena Math | 1502 | — |
| FrontierMath (Feb 2025 set) | 39% | — |
| FrontierMath Tier 4 (v1) | 14.6% | — |
Knowledge Gemini 3.5 Flash leads
Gemini 3.5 Flash: 66.3 (#10), o3-pro: 29.0 (#234)
| Benchmark | Gemini 3.5 Flash | o3-pro |
|---|---|---|
| GPQA Diamond | 92.8% | — |
| SimpleQA Verified | 66.2% | — |
| Confabulations | — | 14.2% |
| Vectara Hallucination Rate | — | 23.3% |
| LMArena Expert | 1493 | — |
Multimodal Not comparable
Gemini 3.5 Flash: 45.7 (#13), o3-pro: —
| Benchmark | Gemini 3.5 Flash | o3-pro |
|---|---|---|
| LMArena Vision | 1311 | — |
| Blueprint-Bench 2 | 33.6% | — |
| LMArena Document | 1463 | — |
Multilingual Not comparable
Gemini 3.5 Flash: 57.1 (#12), o3-pro: —
| Benchmark | Gemini 3.5 Flash | o3-pro |
|---|---|---|
| LMArena Non-English | 1475 | — |
| LMArena Chinese | 1525 | — |
| LMArena French | 1490 | — |
| LMArena German | 1500 | — |
| LMArena Japanese | 1481 | — |
| LMArena Korean | 1453 | — |
| LMArena Russian | 1491 | — |
| LMArena Spanish | 1478 | — |
Instruction Following Not comparable
Gemini 3.5 Flash: 77.2 (#29), o3-pro: —
| Benchmark | Gemini 3.5 Flash | o3-pro |
|---|---|---|
| LMArena Instruction Following | 1466 | — |
Long Context o3-pro leads
Gemini 3.5 Flash: 45.3 (#39), o3-pro: 72.1 (#1)
| Benchmark | Gemini 3.5 Flash | o3-pro |
|---|---|---|
| Fiction.LiveBench | — | 97.2% |
| LMArena Longer Query | 1481 | — |
Writing & Preference Gemini 3.5 Flash leads
Gemini 3.5 Flash: 65.5 (#46), o3-pro: 57.1 (#128)
| Benchmark | Gemini 3.5 Flash | o3-pro |
|---|---|---|
| LMArena Text | 1481 | — |
| LMArena Creative Writing | 1467 | — |
| Short-Story Creative Writing | — | 84.4% |
| EQ-Bench 4 | 1087 | — |
| LMArena Multi-Turn | 1482 | — |
Frequently asked questions
Is Gemini 3.5 Flash better than o3-pro?
Gemini 3.5 Flash is the stronger model overall, scoring 54.1 to 42.7 on the Noometry Index.
Which is cheaper, Gemini 3.5 Flash or o3-pro?
Gemini 3.5 Flash is cheaper. It lists at $1.50 per million input tokens and $9 per million output tokens; o3-pro lists at $20 and $80.
Is Gemini 3.5 Flash or o3-pro better for coding?
o3-pro scores higher on coding benchmarks: 55.1 versus 49.1 in the Noometry coding category.
Which has the bigger context window?
Gemini 3.5 Flash does, with 1.05M tokens against 200K.
How many benchmarks do Gemini 3.5 Flash and o3-pro share?
6 benchmarks have published results for both models. Gemini 3.5 Flash has 54 scored results on Noometry and o3-pro has 12.