Gemini 3.5 Flash vs OpenAI o3
Compare Gemini 3.5 Flash by Google AI against OpenAI o3 by OpenAI, tested across 53 shared challenges. Updated May 2026.
Which is better, Gemini 3.5 Flash or OpenAI o3?
Gemini 3.5 Flash and OpenAI o3 are both competitive models. Gemini 3.5 Flash costs $1.5/M input tokens vs $10/M for OpenAI o3. Compare their real outputs side by side below.
Key Differences Between Gemini 3.5 Flash and OpenAI o3
Gemini 3.5 Flash is made by google while OpenAI o3 is from openai. On pricing, Gemini 3.5 Flash costs $1.5/M input tokens vs $10/M for OpenAI o3.
API pricing
Per 1M tokens
Gemini 3.5 Flash
Input
$1.50
6.7× cheaper
Output
$9.00
4.4× cheaper
OpenAI o3
Input
$10.00
Output
$40.00
Gemini 3.5 Flash is cheaper on both — 6.7× input, 4.4× output
Our Verdict
Gemini 3.5 Flash
OpenAI o3
No community votes yet. On paper, these are closely matched - try both with your actual task to see which fits your workflow.
Gemini 3.5 Flash is 4.4x cheaper per token — worth considering if cost matters.
Too close to call
Writing DNA
Style Comparison
Similarity
47%
Gemini 3.5 Flash uses 6.4x more bold
Gemini 3.5 Flash
OpenAI o3
59%Vocabulary68%
18wSentence Length14w
0.16Hedging0.26
4.4Bold0.7
3.0Lists3.0
0.00Emoji0.00
0.89Headings0.38
0.11Transitions0.12
Based on 27 + 16 text responses
FAQ
