# Gemini 2.5 Flash-Lite vs GPT-5.3 Codex

> GPT-5.3 Codex is the stronger model overall, scoring 45.8 to 37.0 on the Noometry Index. Gemini 2.5 Flash-Lite costs 27× 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-2-5-flash-lite-vs-gpt-5-3-codex
- Last updated: 2026-10-10
- Shared benchmarks: 3

## Summary

- They share 3 benchmarks with published results for both. Gemini 2.5 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 28.0.
- The biggest single-benchmark swing is WeirdML: 35.2% for Gemini 2.5 Flash-Lite and 79.3% for GPT-5.3 Codex.
- Gemini 2.5 Flash-Lite is cheaper at $0.10 / $0.40 per million input/output tokens, against $1.75 / $14 for GPT-5.3 Codex.
- Gemini 2.5 Flash-Lite accepts more context: 1.05M tokens versus 400K.

## Snapshot

| | Gemini 2.5 Flash-Lite | GPT-5.3 Codex |
|---|---|---|
| Provider | Google | OpenAI |
| Noometry Index | 37.0 | 45.8 |
| Rank | 211 | 69 |
| Context | 1.05M | 400K |
| Input $/M | $0.10 | $1.75 |
| Output $/M | $0.40 | $14 |
| Weights | Proprietary | Proprietary |

## Coding

- Gemini 2.5 Flash-Lite: 38.5 (#173)
- GPT-5.3 Codex: 48.6 (#56)

| Benchmark | Gemini 2.5 Flash-Lite | GPT-5.3 Codex |
|---|---|---|
| WeirdML | 35.2% | 79.3% |
| ALE-Bench | 325.9 | 1,655 |
| SWE-bench Verified | — | 74.8% |
| LMArena WebDev | — | 1409 |
| LMArena Coding | 1373 | — |

## Agentic & Tool Use

- Gemini 2.5 Flash-Lite: 28.0 (#96)
- GPT-5.3 Codex: 48.0 (#9)

| Benchmark | Gemini 2.5 Flash-Lite | GPT-5.3 Codex |
|---|---|---|
| Terminal-Bench | — | 78.4% |
| Berkeley Function Calling Leaderboard | 36.9% | — |
| METR Time Horizons | — | 74.5% |
| Vending-Bench 2 | — | 5,940 |

## Reasoning

- Gemini 2.5 Flash-Lite: 22.2 (#205)
- GPT-5.3 Codex: —

| Benchmark | Gemini 2.5 Flash-Lite | GPT-5.3 Codex |
|---|---|---|
| Epoch Capabilities Index | 133.94 | 156.77 |
| Kagi LLM Benchmark | 40.5% | — |
| LMArena Hard Prompts | 1377 | — |
| DTBench | 62.8% | — |
| LMCA | 18.1% | — |

## Math

- Gemini 2.5 Flash-Lite: 38.0 (#144)
- GPT-5.3 Codex: —

| Benchmark | Gemini 2.5 Flash-Lite | GPT-5.3 Codex |
|---|---|---|
| Omni-MATH | 48% | — |
| LMArena Math | 1373 | — |

## Knowledge

- Gemini 2.5 Flash-Lite: 32.5 (#210)
- GPT-5.3 Codex: —

| Benchmark | Gemini 2.5 Flash-Lite | GPT-5.3 Codex |
|---|---|---|
| MMLU-Pro | 53.7% | — |
| Vectara Hallucination Rate | 3.3% | — |
| GPQA (HELM) | 30.9% | — |
| LMArena Expert | 1373 | — |

## Multimodal

- Gemini 2.5 Flash-Lite: 29.1 (#114)
- GPT-5.3 Codex: —

| Benchmark | Gemini 2.5 Flash-Lite | GPT-5.3 Codex |
|---|---|---|
| LMArena Vision | 1198 | — |
| VPCT | 30% | — |

## Multilingual

- Gemini 2.5 Flash-Lite: 49.3 (#134)
- GPT-5.3 Codex: —

| Benchmark | Gemini 2.5 Flash-Lite | GPT-5.3 Codex |
|---|---|---|
| LMArena Non-English | 1369 | — |
| LMArena Chinese | 1404 | — |
| LMArena French | 1388 | — |
| LMArena German | 1389 | — |
| LMArena Japanese | 1359 | — |
| LMArena Korean | 1360 | — |
| LMArena Russian | 1373 | — |
| LMArena Spanish | 1396 | — |

## Instruction Following

- Gemini 2.5 Flash-Lite: 70.0 (#168)
- GPT-5.3 Codex: —

| Benchmark | Gemini 2.5 Flash-Lite | GPT-5.3 Codex |
|---|---|---|
| IFEval | 81% | — |
| LMArena Instruction Following | 1367 | — |

## Long Context

- Gemini 2.5 Flash-Lite: 33.3 (#262)
- GPT-5.3 Codex: —

| Benchmark | Gemini 2.5 Flash-Lite | GPT-5.3 Codex |
|---|---|---|
| Fiction.LiveBench | 47.2% | — |
| LMArena Longer Query | 1373 | — |

## Writing & Preference

- Gemini 2.5 Flash-Lite: 56.8 (#135)
- GPT-5.3 Codex: —

| Benchmark | Gemini 2.5 Flash-Lite | GPT-5.3 Codex |
|---|---|---|
| LMArena Text | 1379 | — |
| LMArena Creative Writing | 1367 | — |
| WildBench | 81.8% | — |
| LMArena Multi-Turn | 1366 | — |

## FAQ

### Is Gemini 2.5 Flash-Lite better than GPT-5.3 Codex?

GPT-5.3 Codex is the stronger model overall, scoring 45.8 to 37.0 on the Noometry Index. Gemini 2.5 Flash-Lite costs 27× 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 2.5 Flash-Lite or GPT-5.3 Codex?

Gemini 2.5 Flash-Lite is cheaper. It lists at $0.10 per million input tokens and $0.40 per million output tokens; GPT-5.3 Codex lists at $1.75 and $14.

### Is Gemini 2.5 Flash-Lite or GPT-5.3 Codex better for coding?

GPT-5.3 Codex scores higher on coding benchmarks: 48.6 versus 38.5 in the Noometry coding category.

### Which has the bigger context window?

Gemini 2.5 Flash-Lite does, with 1.05M tokens against 400K.

### How many benchmarks do Gemini 2.5 Flash-Lite and GPT-5.3 Codex share?

3 benchmarks have published results for both models. Gemini 2.5 Flash-Lite has 33 scored results on Noometry and GPT-5.3 Codex has 8.