# 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.

- Canonical page: https://noometry.com/compare/gemini-3-1-flash-lite-vs-o3-pro
- Last updated: 2026-10-10
- Shared benchmarks: 6

## Summary

- 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.

## Snapshot

| | Gemini 3.1 Flash Lite | o3-pro |
|---|---|---|
| Provider | Google | OpenAI |
| Noometry Index | 40.8 | 42.9 |
| Rank | 144 | 105 |
| Context | 1.05M | 200K |
| Input $/M | $0.25 | $20 |
| Output $/M | $1.50 | $80 |
| Weights | Proprietary | Proprietary |

## Coding

- 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

- Gemini 3.1 Flash Lite: 30.2 (#79)
- o3-pro: —

| Benchmark | Gemini 3.1 Flash Lite | o3-pro |
|---|---|---|
| DeepResearch Bench | 37.3% | — |

## Reasoning

- 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

- 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: 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

- Gemini 3.1 Flash Lite: 39.4 (#60)
- o3-pro: —

| Benchmark | Gemini 3.1 Flash Lite | o3-pro |
|---|---|---|
| LMArena Vision | 1240 | — |

## Multilingual

- 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

- Gemini 3.1 Flash Lite: 72.7 (#131)
- o3-pro: —

| Benchmark | Gemini 3.1 Flash Lite | o3-pro |
|---|---|---|
| LMArena Instruction Following | 1377 | — |

## Long Context

- 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: 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 | — |

## FAQ

### 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.