Model comparison

Gemma 3 12B vs o3-pro

o3-pro is the stronger model overall, scoring 42.9 to 32.1 on the Noometry Index. Gemma 3 12B costs 467× less per token, which makes it the better buy when o3-pro's lead doesn't matter for your workload.

Last verified October 10, 2026. 4 shared benchmarks.

Gemma 3 12B

Google

32.1

Rank #262 Confirmed

o3-pro OpenAI

42.9

Rank #105 Confirmed

Summary

They share 4 benchmarks with published results for both. Gemma 3 12B scores higher in 0 categories and o3-pro in 5 categories; 5 gaps are clear of the uncertainty.
The widest gap is in long context, where o3-pro leads 72.2 to 40.0.
The biggest single-benchmark swing is DTBench: 48.8% for Gemma 3 12B and 86.9% for o3-pro.
Gemma 3 12B is cheaper at $0.05 / $0.15 per million input/output tokens, against $20 / $80 for o3-pro.
o3-pro accepts more context: 200K tokens versus 131K.
Gemma 3 12B has downloadable open weights; the other is API-only.

Side by side

Gemma 3 12B and o3-pro specifications
	Gemma 3 12B	o3-pro
Provider	Google	OpenAI
Noometry Index	32.1	42.9
Released	2025-03-12	2025-06-10
Weights	Open	Proprietary
Context window	131K	200K
Max output	8K	100K
Input $ / M tokens	$0.05	$20
Output $ / M tokens	$0.15	$80
Results tracked	24	12

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Category by category

Coding o3-pro leads

Gemma 3 12B: 31.7 (#280), o3-pro: 55.5 (#24)

Coding benchmarks
Benchmark	Gemma 3 12B	o3-pro
Aider Polyglot	—	84.9%
SciCode	17.4%	—
WeirdML	—	58.2%
LMArena Coding	1281	—

Agentic & Tool Use Not comparable

Gemma 3 12B: 25.5 (#108), o3-pro: —

Agentic & Tool Use benchmarks
Benchmark	Gemma 3 12B	o3-pro
Berkeley Function Calling Leaderboard	30.4%	—

Reasoning o3-pro leads

Gemma 3 12B: 15.7 (#313), o3-pro: 23.8 (#171)

Reasoning benchmarks
Benchmark	Gemma 3 12B	o3-pro
DTBench	48.8%	86.9%
LMCA	4.5%	38.5%
Epoch Capabilities Index	123.5	147.42
ARC-AGI-2	—	4.9%
Kagi LLM Benchmark	—	72.1%
ARC-AGI-1	—	59.3%
CritPt	0%	—
Chess Puzzles	0%	—
LMArena Hard Prompts	1309	—

Math Not comparable

Gemma 3 12B: 22.3 (#279), o3-pro: —

Math benchmarks
Benchmark	Gemma 3 12B	o3-pro
OTIS Mock AIME 2024-2025	16.7%	—
LMArena Math	1307	—

Knowledge o3-pro leads

Gemma 3 12B: 26.5 (#257), o3-pro: 29.5 (#238)

Knowledge benchmarks
Benchmark	Gemma 3 12B	o3-pro
Vectara Hallucination Rate	4.4%	23.3%
GPQA Diamond	39.5%	—
Confabulations	—	14.2%
LMArena Expert	1248	—

Multimodal Not comparable

Gemma 3 12B: —, o3-pro: —

Multimodal benchmarks
Benchmark	Gemma 3 12B	o3-pro
MindCube	46.7%	—

Multilingual Not comparable

Gemma 3 12B: 45.7 (#165), o3-pro: —

Multilingual benchmarks
Benchmark	Gemma 3 12B	o3-pro
LMArena Non-English	1318	—
LMArena German	1370	—
LMArena Russian	1335	—

Instruction Following Not comparable

Gemma 3 12B: 68.6 (#186), o3-pro: —

Instruction Following benchmarks
Benchmark	Gemma 3 12B	o3-pro
LMArena Instruction Following	1299	—

Long Context o3-pro leads

Gemma 3 12B: 40.0 (#162), o3-pro: 72.2 (#1)

Long Context benchmarks
Benchmark	Gemma 3 12B	o3-pro
Fiction.LiveBench	—	97.2%
LMArena Longer Query	1317	—

Writing & Preference o3-pro leads

Gemma 3 12B: 47.5 (#209), o3-pro: 57.1 (#133)

Writing & Preference benchmarks
Benchmark	Gemma 3 12B	o3-pro
LMArena Text	1334	—
LMArena Creative Writing	1331	—
Short-Story Creative Writing	—	84.4%
EQ-Bench Creative Writing	1126	—
LMArena Multi-Turn	1334	—

Frequently asked questions

Is Gemma 3 12B better than o3-pro?

Which is cheaper, Gemma 3 12B or o3-pro?

Gemma 3 12B is cheaper. It lists at $0.05 per million input tokens and $0.15 per million output tokens; o3-pro lists at $20 and $80.

Is Gemma 3 12B or o3-pro better for coding?

o3-pro scores higher on coding benchmarks: 55.5 versus 31.7 in the Noometry coding category.

Which has the bigger context window?

o3-pro does, with 200K tokens against 131K.

How many benchmarks do Gemma 3 12B and o3-pro share?

4 benchmarks have published results for both models. Gemma 3 12B has 24 scored results on Noometry and o3-pro has 12.