# Gemini 3.5 Flash Lite vs GPT-5.3 Codex

> GPT-5.3 Codex is the stronger model overall, scoring 45.8 to 41.5 on the Noometry Index. Gemini 3.5 Flash Lite costs 5.7× less per token, which makes it the better buy when GPT-5.3 Codex's lead doesn't matter for your workload.

- Canonical page: https://noometry.com/compare/gemini-3-5-flash-lite-vs-gpt-5-3-codex
- Last updated: 2026-10-10
- Shared benchmarks: 4

## Summary

- They share 4 benchmarks with published results for both. Gemini 3.5 Flash Lite scores higher in 0 categories and GPT-5.3 Codex in 2 categories; 2 gaps are clear of the uncertainty.
- The widest gap is in agentic & tool use, where GPT-5.3 Codex leads 48.0 to 25.7.
- The biggest single-benchmark swing is WeirdML: 39% for Gemini 3.5 Flash Lite and 79.3% for GPT-5.3 Codex.
- Gemini 3.5 Flash Lite is cheaper at $0.30 / $2.50 per million input/output tokens, against $1.75 / $14 for GPT-5.3 Codex.
- Gemini 3.5 Flash Lite accepts more context: 1.05M tokens versus 400K.

## Snapshot

| | Gemini 3.5 Flash Lite | GPT-5.3 Codex |
|---|---|---|
| Provider | Google | OpenAI |
| Noometry Index | 41.5 | 45.8 |
| Rank | 133 | 69 |
| Context | 1.05M | 400K |
| Input $/M | $0.30 | $1.75 |
| Output $/M | $2.50 | $14 |
| Weights | Proprietary | Proprietary |

## Coding

- Gemini 3.5 Flash Lite: 42.4 (#104)
- GPT-5.3 Codex: 48.6 (#56)

| Benchmark | Gemini 3.5 Flash Lite | GPT-5.3 Codex |
|---|---|---|
| LMArena WebDev | 1440 | 1409 |
| WeirdML | 39% | 79.3% |
| ALE-Bench | 765.27 | 1,655 |
| SWE-bench Verified | — | 74.8% |
| SciCode | 41.3% | — |
| LMArena Coding | 1453 | — |

## Agentic & Tool Use

- Gemini 3.5 Flash Lite: 25.7 (#107)
- GPT-5.3 Codex: 48.0 (#9)

| Benchmark | Gemini 3.5 Flash Lite | GPT-5.3 Codex |
|---|---|---|
| Terminal-Bench | — | 78.4% |
| APEX-Agents | 29.3% | — |
| GDP.pdf | 10% | — |
| METR Time Horizons | — | 74.5% |
| Vending-Bench 2 | — | 5,940 |

## Reasoning

- Gemini 3.5 Flash Lite: 27.8 (#114)
- GPT-5.3 Codex: —

| Benchmark | Gemini 3.5 Flash Lite | GPT-5.3 Codex |
|---|---|---|
| Epoch Capabilities Index | 145.13 | 156.77 |
| ARC-AGI-2 | 10.3% | — |
| NYT Connections (extended) | 60.4% | — |
| ARC-AGI-1 | 53.5% | — |
| CritPt | 0% | — |
| Chess Puzzles | 22% | — |
| LMArena Hard Prompts | 1441 | — |
| Mystery Game Puzzles | 19% | — |
| DTBench | 83.5% | — |
| LMCA | 37.6% | — |

## Math

- Gemini 3.5 Flash Lite: 25.9 (#264)
- GPT-5.3 Codex: —

| Benchmark | Gemini 3.5 Flash Lite | GPT-5.3 Codex |
|---|---|---|
| FrontierMath (Tiers 1-3) | 26% | — |
| FrontierMath Tier 4 | 0% | — |
| OTIS Mock AIME 2024-2025 | 71.1% | — |
| ProofBench | 13% | — |
| LMArena Math | 1433 | — |

## Knowledge

- Gemini 3.5 Flash Lite: 50.1 (#72)
- GPT-5.3 Codex: —

| Benchmark | Gemini 3.5 Flash Lite | GPT-5.3 Codex |
|---|---|---|
| GPQA Diamond | 83.3% | — |
| LMArena Expert | 1435 | — |

## Multimodal

- Gemini 3.5 Flash Lite: 41.1 (#40)
- GPT-5.3 Codex: —

| Benchmark | Gemini 3.5 Flash Lite | GPT-5.3 Codex |
|---|---|---|
| LMArena Vision | 1268 | — |

## Multilingual

- Gemini 3.5 Flash Lite: 53.5 (#63)
- GPT-5.3 Codex: —

| Benchmark | Gemini 3.5 Flash Lite | GPT-5.3 Codex |
|---|---|---|
| LMArena Non-English | 1427 | — |
| LMArena Chinese | 1469 | — |
| LMArena French | 1451 | — |
| LMArena German | 1454 | — |
| LMArena Japanese | 1427 | — |
| LMArena Korean | 1407 | — |
| LMArena Russian | 1443 | — |
| LMArena Spanish | 1442 | — |

## Instruction Following

- Gemini 3.5 Flash Lite: 74.8 (#85)
- GPT-5.3 Codex: —

| Benchmark | Gemini 3.5 Flash Lite | GPT-5.3 Codex |
|---|---|---|
| LMArena Instruction Following | 1420 | — |

## Long Context

- Gemini 3.5 Flash Lite: 43.9 (#84)
- GPT-5.3 Codex: —

| Benchmark | Gemini 3.5 Flash Lite | GPT-5.3 Codex |
|---|---|---|
| LMArena Longer Query | 1435 | — |

## Writing & Preference

- Gemini 3.5 Flash Lite: 64.2 (#57)
- GPT-5.3 Codex: —

| Benchmark | Gemini 3.5 Flash Lite | GPT-5.3 Codex |
|---|---|---|
| LMArena Text | 1435 | — |
| LMArena Creative Writing | 1420 | — |
| EQ-Bench Creative Writing | 1559 | — |
| LMArena Multi-Turn | 1445 | — |

## FAQ

### Is Gemini 3.5 Flash Lite better than GPT-5.3 Codex?

GPT-5.3 Codex is the stronger model overall, scoring 45.8 to 41.5 on the Noometry Index. Gemini 3.5 Flash Lite costs 5.7× less per token, which makes it the better buy when GPT-5.3 Codex's lead doesn't matter for your workload.

### Which is cheaper, Gemini 3.5 Flash Lite or GPT-5.3 Codex?

Gemini 3.5 Flash Lite is cheaper. It lists at $0.30 per million input tokens and $2.50 per million output tokens; GPT-5.3 Codex lists at $1.75 and $14.

### Is Gemini 3.5 Flash Lite or GPT-5.3 Codex better for coding?

GPT-5.3 Codex scores higher on coding benchmarks: 48.6 versus 42.4 in the Noometry coding category.

### Which has the bigger context window?

Gemini 3.5 Flash Lite does, with 1.05M tokens against 400K.

### How many benchmarks do Gemini 3.5 Flash Lite and GPT-5.3 Codex share?

4 benchmarks have published results for both models. Gemini 3.5 Flash Lite has 39 scored results on Noometry and GPT-5.3 Codex has 8.