Model comparison
Gemini 3.1 Flash Lite vs o3-pro
o3-pro is the stronger model overall, scoring 42.9 to 40.8 on the Noometry Index. Gemini 3.1 Flash Lite costs 62× less per token, which makes it the better buy when o3-pro's lead doesn't matter for your workload.
Last verified . 6 shared benchmarks.
GoogleSummary
- They share 6 benchmarks with published results for both. Gemini 3.1 Flash Lite scores higher in 2 categories and o3-pro in 3 categories; 4 gaps are clear of the uncertainty.
- The widest gap is in long context, where o3-pro leads 72.2 to 42.5.
- The biggest single-benchmark swing is Vectara Hallucination Rate: 8.2% for Gemini 3.1 Flash Lite and 23.3% for o3-pro.
- Gemini 3.1 Flash Lite is cheaper at $0.25 / $1.50 per million input/output tokens, against $20 / $80 for o3-pro.
- Gemini 3.1 Flash Lite accepts more context: 1.05M tokens versus 200K.
Side by side
| Gemini 3.1 Flash Lite | o3-pro | |
|---|---|---|
| Provider | OpenAI | |
| Noometry Index | 40.8 | 42.9 |
| Released | 2026-03-03 | 2025-06-10 |
| Weights | Proprietary | Proprietary |
| Context window | 1.05M | 200K |
| Max output | 66K | 100K |
| Input $ / M tokens | $0.25 | $20 |
| Output $ / M tokens | $1.50 | $80 |
| Results tracked | 38 | 12 |
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Category by category
Coding o3-pro leads
Gemini 3.1 Flash Lite: 37.8 (#188), o3-pro: 55.5 (#24)
| Benchmark | Gemini 3.1 Flash Lite | o3-pro |
|---|---|---|
| WeirdML | 52.2% | 58.2% |
| Aider Polyglot | — | 84.9% |
| LMArena WebDev | 1256 | — |
| SciCode | 41.9% | — |
| LMArena Coding | 1400 | — |
| ALE-Bench | 797.73 | — |
Agentic & Tool Use Not comparable
Gemini 3.1 Flash Lite: 30.2 (#79), o3-pro: —
| Benchmark | Gemini 3.1 Flash Lite | o3-pro |
|---|---|---|
| DeepResearch Bench | 37.3% | — |
Reasoning Too close to call
Gemini 3.1 Flash Lite: 22.9 (#186), o3-pro: 23.8 (#171)
| Benchmark | Gemini 3.1 Flash Lite | o3-pro |
|---|---|---|
| Kagi LLM Benchmark | 67.2% | 72.1% |
| DTBench | 76.8% | 86.9% |
| LMCA | 35% | 38.5% |
| Epoch Capabilities Index | 144.47 | 147.42 |
| ARC-AGI-2 | — | 4.9% |
| NYT Connections (extended) | 8.2% | — |
| ARC-AGI-1 | — | 59.3% |
| CritPt | 1.1% | — |
| Chess Puzzles | 25% | — |
| EnigmaEval | 3% | — |
| Thematic Generalization | 63.3% | — |
| LMArena Hard Prompts | 1407 | — |
| ForecastBench | 54.4 | — |
Math Not comparable
Gemini 3.1 Flash Lite: 40.7 (#90), o3-pro: —
| Benchmark | Gemini 3.1 Flash Lite | o3-pro |
|---|---|---|
| FrontierMath (Tiers 1-3) | 27.7% | — |
| OTIS Mock AIME 2024-2025 | 80% | — |
| LMArena Math | 1428 | — |
Knowledge Gemini 3.1 Flash Lite leads
Gemini 3.1 Flash Lite: 41.9 (#104), o3-pro: 29.5 (#238)
| Benchmark | Gemini 3.1 Flash Lite | o3-pro |
|---|---|---|
| Vectara Hallucination Rate | 8.2% | 23.3% |
| GPQA Diamond | 81.8% | — |
| Humanity's Last Exam | 8.6% | — |
| Confabulations | — | 14.2% |
| LMArena Expert | 1398 | — |
Multimodal Not comparable
Gemini 3.1 Flash Lite: 39.4 (#60), o3-pro: —
| Benchmark | Gemini 3.1 Flash Lite | o3-pro |
|---|---|---|
| LMArena Vision | 1240 | — |
Multilingual Not comparable
Gemini 3.1 Flash Lite: 52.3 (#86), o3-pro: —
| Benchmark | Gemini 3.1 Flash Lite | o3-pro |
|---|---|---|
| LMArena Non-English | 1411 | — |
| LMArena Chinese | 1461 | — |
| LMArena French | 1424 | — |
| LMArena German | 1429 | — |
| LMArena Japanese | 1413 | — |
| LMArena Korean | 1392 | — |
| LMArena Russian | 1420 | — |
| LMArena Spanish | 1421 | — |
Instruction Following Not comparable
Gemini 3.1 Flash Lite: 72.7 (#131), o3-pro: —
| Benchmark | Gemini 3.1 Flash Lite | o3-pro |
|---|---|---|
| LMArena Instruction Following | 1377 | — |
Long Context o3-pro leads
Gemini 3.1 Flash Lite: 42.5 (#122), o3-pro: 72.2 (#1)
| Benchmark | Gemini 3.1 Flash Lite | o3-pro |
|---|---|---|
| Fiction.LiveBench | — | 97.2% |
| LMArena Longer Query | 1394 | — |
Writing & Preference Gemini 3.1 Flash Lite leads
Gemini 3.1 Flash Lite: 60.9 (#94), o3-pro: 57.1 (#133)
| Benchmark | Gemini 3.1 Flash Lite | o3-pro |
|---|---|---|
| LMArena Text | 1416 | — |
| LMArena Creative Writing | 1401 | — |
| Short-Story Creative Writing | — | 84.4% |
| LMArena Multi-Turn | 1417 | — |
Frequently asked questions
Is Gemini 3.1 Flash Lite better than o3-pro?
o3-pro is the stronger model overall, scoring 42.9 to 40.8 on the Noometry Index. Gemini 3.1 Flash Lite costs 62× less per token, which makes it the better buy when o3-pro's lead doesn't matter for your workload.
Which is cheaper, Gemini 3.1 Flash Lite or o3-pro?
Gemini 3.1 Flash Lite is cheaper. It lists at $0.25 per million input tokens and $1.50 per million output tokens; o3-pro lists at $20 and $80.
Is Gemini 3.1 Flash Lite or o3-pro better for coding?
o3-pro scores higher on coding benchmarks: 55.5 versus 37.8 in the Noometry coding category.
Which has the bigger context window?
Gemini 3.1 Flash Lite does, with 1.05M tokens against 200K.
How many benchmarks do Gemini 3.1 Flash Lite and o3-pro share?
6 benchmarks have published results for both models. Gemini 3.1 Flash Lite has 38 scored results on Noometry and o3-pro has 12.