Model comparison

Gemini 2.5 Flash-Lite vs GPT-5-Codex

Gemini 2.5 Flash-Lite and GPT-5-Codex score almost the same on the Noometry Index (37.0 vs 37.9), so choose on price, context window or the category you care about most.

Last verified October 10, 2026. 2 shared benchmarks.

Gemini 2.5 Flash-Lite

Google

37.0

Rank #211 Confirmed

GPT-5-Codex OpenAI

37.9

Rank #192 Reported

Summary

They share 2 benchmarks with published results for both. Gemini 2.5 Flash-Lite scores higher in 0 categories and GPT-5-Codex in 3 categories; 3 gaps are clear of the uncertainty.
The widest gap is in reasoning, where GPT-5-Codex leads 30.9 to 22.2.
The biggest single-benchmark swing is Kagi LLM Benchmark: 40.5% for Gemini 2.5 Flash-Lite and 70.3% for GPT-5-Codex.
Gemini 2.5 Flash-Lite is cheaper at $0.10 / $0.40 per million input/output tokens, against $1.25 / $10 for GPT-5-Codex.
Gemini 2.5 Flash-Lite accepts more context: 1.05M tokens versus 400K.

Side by side

Gemini 2.5 Flash-Lite and GPT-5-Codex specifications
	Gemini 2.5 Flash-Lite	GPT-5-Codex
Provider	Google	OpenAI
Noometry Index	37.0	37.9
Released	2025-06-17	2025-09-15
Weights	Proprietary	Proprietary
Context window	1.05M	400K
Max output	66K	128K
Input $ / M tokens	$0.10	$1.25
Output $ / M tokens	$0.40	$10
Results tracked	33	3

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Category by category

Coding GPT-5-Codex leads

Gemini 2.5 Flash-Lite: 38.5 (#173), GPT-5-Codex: 42.4 (#103)

Coding benchmarks
Benchmark	Gemini 2.5 Flash-Lite	GPT-5-Codex
WeirdML	35.2%	54.5%
LMArena Coding	1373	—
ALE-Bench	325.9	—

Agentic & Tool Use GPT-5-Codex leads

Gemini 2.5 Flash-Lite: 28.0 (#96), GPT-5-Codex: 31.0 (#72)

Agentic & Tool Use benchmarks
Benchmark	Gemini 2.5 Flash-Lite	GPT-5-Codex
Terminal-Bench	—	44.3%
Berkeley Function Calling Leaderboard	36.9%	—

Reasoning GPT-5-Codex leads

Gemini 2.5 Flash-Lite: 22.2 (#205), GPT-5-Codex: 30.9 (#83)

Reasoning benchmarks
Benchmark	Gemini 2.5 Flash-Lite	GPT-5-Codex
Kagi LLM Benchmark	40.5%	70.3%
LMArena Hard Prompts	1377	—
DTBench	62.8%	—
LMCA	18.1%	—
Epoch Capabilities Index	133.94	—

Math Not comparable

Gemini 2.5 Flash-Lite: 38.0 (#144), GPT-5-Codex: —

Math benchmarks
Benchmark	Gemini 2.5 Flash-Lite	GPT-5-Codex
Omni-MATH	48%	—
LMArena Math	1373	—

Knowledge Not comparable

Gemini 2.5 Flash-Lite: 32.5 (#210), GPT-5-Codex: —

Knowledge benchmarks
Benchmark	Gemini 2.5 Flash-Lite	GPT-5-Codex
MMLU-Pro	53.7%	—
Vectara Hallucination Rate	3.3%	—
GPQA (HELM)	30.9%	—
LMArena Expert	1373	—

Multimodal Not comparable

Gemini 2.5 Flash-Lite: 29.1 (#114), GPT-5-Codex: —

Multimodal benchmarks
Benchmark	Gemini 2.5 Flash-Lite	GPT-5-Codex
LMArena Vision	1198	—
VPCT	30%	—

Multilingual Not comparable

Gemini 2.5 Flash-Lite: 49.3 (#134), GPT-5-Codex: —

Multilingual benchmarks
Benchmark	Gemini 2.5 Flash-Lite	GPT-5-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 Not comparable

Gemini 2.5 Flash-Lite: 70.0 (#168), GPT-5-Codex: —

Instruction Following benchmarks
Benchmark	Gemini 2.5 Flash-Lite	GPT-5-Codex
IFEval	81%	—
LMArena Instruction Following	1367	—

Long Context Not comparable

Gemini 2.5 Flash-Lite: 33.3 (#262), GPT-5-Codex: —

Long Context benchmarks
Benchmark	Gemini 2.5 Flash-Lite	GPT-5-Codex
Fiction.LiveBench	47.2%	—
LMArena Longer Query	1373	—

Writing & Preference Not comparable

Gemini 2.5 Flash-Lite: 56.8 (#135), GPT-5-Codex: —

Writing & Preference benchmarks
Benchmark	Gemini 2.5 Flash-Lite	GPT-5-Codex
LMArena Text	1379	—
LMArena Creative Writing	1367	—
WildBench	81.8%	—
LMArena Multi-Turn	1366	—

Frequently asked questions

Is Gemini 2.5 Flash-Lite better than GPT-5-Codex?

Gemini 2.5 Flash-Lite and GPT-5-Codex score almost the same on the Noometry Index (37.0 vs 37.9), so choose on price, context window or the category you care about most.

Which is cheaper, Gemini 2.5 Flash-Lite or GPT-5-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-Codex lists at $1.25 and $10.

Is Gemini 2.5 Flash-Lite or GPT-5-Codex better for coding?

GPT-5-Codex scores higher on coding benchmarks: 42.4 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-Codex share?

2 benchmarks have published results for both models. Gemini 2.5 Flash-Lite has 33 scored results on Noometry and GPT-5-Codex has 3.