Model comparison

Gemini 3.8 Flash vs o3-pro

Gemini 3.8 Flash is the stronger model overall, scoring 61.8 to 42.9 on the Noometry Index.

Last verified . 6 shared benchmarks.

Gemini 3.8 Flash Google

61.8

Rank #11 Confirmed

o3-pro OpenAI

42.9

Rank #105 Confirmed

Summary

  • They share 6 benchmarks with published results for both. Gemini 3.8 Flash scores higher in 4 categories and o3-pro in 1 category; 5 gaps are clear of the uncertainty.
  • The widest gap is in reasoning, where Gemini 3.8 Flash leads 76.9 to 23.8.
  • The biggest single-benchmark swing is ARC-AGI-2: 89.2% for Gemini 3.8 Flash and 4.9% for o3-pro.
  • Gemini 3.8 Flash is cheaper at $0.75 / $3.75 per million input/output tokens, against $20 / $80 for o3-pro.
  • Gemini 3.8 Flash accepts more context: 1.05M tokens versus 200K.

Side by side

Gemini 3.8 Flash and o3-pro specifications
Gemini 3.8 Flasho3-pro
ProviderGoogleOpenAI
Noometry Index61.842.9
Released2026-09-022025-06-10
WeightsProprietaryProprietary
Context window1.05M200K
Max output66K100K
Input $ / M tokens$0.75$20
Output $ / M tokens$3.75$80
Results tracked5012

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Category by category

Coding Gemini 3.8 Flash leads

Gemini 3.8 Flash: 59.2 (#15), o3-pro: 55.5 (#24)

Coding benchmarks
BenchmarkGemini 3.8 Flasho3-pro
WeirdML84.8%58.2%
DeepSWE73.8%—
FrontierCode41.2%—
Aider Polyglot—84.9%
CursorBench39.6%—
LMArena WebDev1584—
FrontierSWE19.6%—
SciCode56.6%—
LMArena Coding1510—
ALE-Bench1,270—

Agentic & Tool Use Not comparable

Gemini 3.8 Flash: 41.8 (#21), o3-pro: —

Agentic & Tool Use benchmarks
BenchmarkGemini 3.8 Flasho3-pro
APEX-Agents64.3%—
Remote Labor Index5.8%—
GDP.pdf23.4%—
Vending-Bench 25,094—

Reasoning Gemini 3.8 Flash leads

Gemini 3.8 Flash: 76.9 (#5), o3-pro: 23.8 (#171)

Reasoning benchmarks
BenchmarkGemini 3.8 Flasho3-pro
ARC-AGI-289.2%4.9%
ARC-AGI-198.5%59.3%
DTBench95.7%86.9%
LMCA52.9%38.5%
Epoch Capabilities Index156.71147.42
Kagi LLM Benchmark—72.1%
NYT Connections (extended)97.4%—
CritPt18.3%—
Chess Puzzles61%—
LMArena Hard Prompts1508—
Mystery Game Puzzles47%—
Surface Evolver Bench76.9%—

Math Not comparable

Gemini 3.8 Flash: 65.3 (#28), o3-pro: —

Math benchmarks
BenchmarkGemini 3.8 Flasho3-pro
FrontierMath (Tiers 1-3)68.4%—
FrontierMath Tier 422%—
OTIS Mock AIME 2024-202598.9%—
ProofBench48%—
LMArena Math1528—

Knowledge Gemini 3.8 Flash leads

Gemini 3.8 Flash: 74.8 (#2), o3-pro: 29.5 (#238)

Knowledge benchmarks
BenchmarkGemini 3.8 Flasho3-pro
GPQA Diamond95.4%—
Humanity's Last Exam44.5%—
SimpleQA Verified69.7%—
Confabulations—14.2%
Vectara Hallucination Rate—23.3%
LMArena Expert1524—

Multimodal Not comparable

Gemini 3.8 Flash: 40.7 (#45), o3-pro: —

Multimodal benchmarks
BenchmarkGemini 3.8 Flasho3-pro
LMArena Vision1314—
Blueprint-Bench 238.6%—
Furniture Assembly31.7%—

Multilingual Not comparable

Gemini 3.8 Flash: 58.0 (#5), o3-pro: —

Multilingual benchmarks
BenchmarkGemini 3.8 Flasho3-pro
LMArena Non-English1491—
LMArena Chinese1554—
LMArena French1498—
LMArena German1493—
LMArena Japanese1502—
LMArena Korean1459—
LMArena Russian1515—
LMArena Spanish1485—

Instruction Following Not comparable

Gemini 3.8 Flash: 78.0 (#13), o3-pro: —

Instruction Following benchmarks
BenchmarkGemini 3.8 Flasho3-pro
LMArena Instruction Following1490—

Long Context o3-pro leads

Gemini 3.8 Flash: 46.3 (#24), o3-pro: 72.2 (#1)

Long Context benchmarks
BenchmarkGemini 3.8 Flasho3-pro
Fiction.LiveBench—97.2%
LMArena Longer Query1508—

Writing & Preference Gemini 3.8 Flash leads

Gemini 3.8 Flash: 72.2 (#15), o3-pro: 57.1 (#133)

Writing & Preference benchmarks
BenchmarkGemini 3.8 Flasho3-pro
LMArena Text1499—
LMArena Creative Writing1492—
Short-Story Creative Writing—84.4%
EQ-Bench Creative Writing1748—
LMArena Multi-Turn1501—

Frequently asked questions

Is Gemini 3.8 Flash better than o3-pro?

Gemini 3.8 Flash is the stronger model overall, scoring 61.8 to 42.9 on the Noometry Index.

Which is cheaper, Gemini 3.8 Flash or o3-pro?

Gemini 3.8 Flash is cheaper. It lists at $0.75 per million input tokens and $3.75 per million output tokens; o3-pro lists at $20 and $80.

Is Gemini 3.8 Flash or o3-pro better for coding?

Gemini 3.8 Flash scores higher on coding benchmarks: 59.2 versus 55.5 in the Noometry coding category.

Which has the bigger context window?

Gemini 3.8 Flash does, with 1.05M tokens against 200K.

How many benchmarks do Gemini 3.8 Flash and o3-pro share?

6 benchmarks have published results for both models. Gemini 3.8 Flash has 50 scored results on Noometry and o3-pro has 12.

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