Model comparison

Gemma 3 12B vs GPT-5.2 Codex

GPT-5.2 Codex is the stronger model overall, scoring 42.6 to 32.1 on the Noometry Index. Gemma 3 12B costs 64× less per token, which makes it the better buy when GPT-5.2 Codex's lead doesn't matter for your workload.

Last verified October 11, 2026. 0 shared benchmarks.

Gemma 3 12B

Google

32.1

Rank #262 Confirmed

GPT-5.2 Codex OpenAI

42.6

Rank #111 Reported

Summary

The widest gap is in agentic & tool use, where GPT-5.2 Codex leads 41.0 to 25.5.
Gemma 3 12B is cheaper at $0.05 / $0.15 per million input/output tokens, against $1.75 / $14 for GPT-5.2 Codex.
GPT-5.2 Codex accepts more context: 400K tokens versus 131K.
Gemma 3 12B has downloadable open weights; the other is API-only.

Side by side

Gemma 3 12B and GPT-5.2 Codex specifications
	Gemma 3 12B	GPT-5.2 Codex
Provider	Google	OpenAI
Noometry Index	32.1	42.6
Released	2025-03-12	2025-12-18
Weights	Open	Proprietary
Context window	131K	400K
Max output	8K	128K
Input $ / M tokens	$0.05	$1.75
Output $ / M tokens	$0.15	$14
Results tracked	24	5

Sponsored placements are available on pages like this one. Advertise on Noometry

Category by category

Coding GPT-5.2 Codex leads

Gemma 3 12B: 31.7 (#280), GPT-5.2 Codex: 45.5 (#71)

Coding benchmarks
Benchmark	Gemma 3 12B	GPT-5.2 Codex
SWE-bench Verified (bash only)	—	72.8%
LMArena WebDev	—	1339
SWE-bench Multilingual	—	66.3%
SciCode	17.4%	—
LMArena Coding	1281	—
ALE-Bench	—	1,300

Agentic & Tool Use GPT-5.2 Codex leads

Gemma 3 12B: 25.5 (#108), GPT-5.2 Codex: 41.0 (#22)

Agentic & Tool Use benchmarks
Benchmark	Gemma 3 12B	GPT-5.2 Codex
Terminal-Bench	—	66.5%
Berkeley Function Calling Leaderboard	30.4%	—

Reasoning Not comparable

Gemma 3 12B: 15.7 (#313), GPT-5.2 Codex: —

Reasoning benchmarks
Benchmark	Gemma 3 12B	GPT-5.2 Codex
CritPt	0%	—
Chess Puzzles	0%	—
LMArena Hard Prompts	1309	—
DTBench	48.8%	—
LMCA	4.5%	—
Epoch Capabilities Index	123.5	—

Math Not comparable

Gemma 3 12B: 22.3 (#279), GPT-5.2 Codex: —

Math benchmarks
Benchmark	Gemma 3 12B	GPT-5.2 Codex
OTIS Mock AIME 2024-2025	16.7%	—
LMArena Math	1307	—

Knowledge Not comparable

Gemma 3 12B: 26.5 (#257), GPT-5.2 Codex: —

Knowledge benchmarks
Benchmark	Gemma 3 12B	GPT-5.2 Codex
GPQA Diamond	39.5%	—
Vectara Hallucination Rate	4.4%	—
LMArena Expert	1248	—

Multimodal Not comparable

Gemma 3 12B: —, GPT-5.2 Codex: —

Multimodal benchmarks
Benchmark	Gemma 3 12B	GPT-5.2 Codex
MindCube	46.7%	—

Multilingual Not comparable

Gemma 3 12B: 45.7 (#165), GPT-5.2 Codex: —

Multilingual benchmarks
Benchmark	Gemma 3 12B	GPT-5.2 Codex
LMArena Non-English	1318	—
LMArena German	1370	—
LMArena Russian	1335	—

Instruction Following Not comparable

Gemma 3 12B: 68.6 (#186), GPT-5.2 Codex: —

Instruction Following benchmarks
Benchmark	Gemma 3 12B	GPT-5.2 Codex
LMArena Instruction Following	1299	—

Long Context Not comparable

Gemma 3 12B: 40.0 (#162), GPT-5.2 Codex: —

Long Context benchmarks
Benchmark	Gemma 3 12B	GPT-5.2 Codex
LMArena Longer Query	1317	—

Writing & Preference Not comparable

Gemma 3 12B: 47.5 (#209), GPT-5.2 Codex: —

Writing & Preference benchmarks
Benchmark	Gemma 3 12B	GPT-5.2 Codex
LMArena Text	1334	—
LMArena Creative Writing	1331	—
EQ-Bench Creative Writing	1126	—
LMArena Multi-Turn	1334	—

Frequently asked questions

Is Gemma 3 12B better than GPT-5.2 Codex?

Which is cheaper, Gemma 3 12B or GPT-5.2 Codex?

Gemma 3 12B is cheaper. It lists at $0.05 per million input tokens and $0.15 per million output tokens; GPT-5.2 Codex lists at $1.75 and $14.

Is Gemma 3 12B or GPT-5.2 Codex better for coding?

GPT-5.2 Codex scores higher on coding benchmarks: 45.5 versus 31.7 in the Noometry coding category.

Which has the bigger context window?

GPT-5.2 Codex does, with 400K tokens against 131K.

How many benchmarks do Gemma 3 12B and GPT-5.2 Codex share?

0 benchmarks have published results for both models. Gemma 3 12B has 24 scored results on Noometry and GPT-5.2 Codex has 5.