Gemini 3.5 Flash vs OpenAI o4-mini
Compare Gemini 3.5 Flash by Google AI against OpenAI o4-mini by OpenAI, tested across 53 shared challenges. Updated May 2026.
Which is better, Gemini 3.5 Flash or OpenAI o4-mini?
Gemini 3.5 Flash and OpenAI o4-mini are both competitive models. Gemini 3.5 Flash costs $1.5/M input tokens vs $1.1/M for OpenAI o4-mini. Compare their real outputs side by side below.
Key Differences Between Gemini 3.5 Flash and OpenAI o4-mini
Gemini 3.5 Flash is made by google while OpenAI o4-mini is from openai. On pricing, Gemini 3.5 Flash costs $1.5/M input tokens vs $1.1/M for OpenAI o4-mini.
API pricing
Per 1M tokens
Gemini 3.5 Flash
Input
$1.50
Output
$9.00
OpenAI o4-mini
Input
$1.10
1.4× cheaper
Output
$4.40
2.0× cheaper
OpenAI o4-mini is cheaper on both — 1.4× input, 2.0× output
Our Verdict
Gemini 3.5 Flash
OpenAI o4-miniRunner-up
No community votes yet. On paper, Gemini 3.5 Flash has the edge — bigger model tier, newer, bigger context window.
Too close to call
Writing DNA
Style Comparison
Similarity
56%
Gemini 3.5 Flash uses 442.3x more bold
Gemini 3.5 Flash
OpenAI o4-mini
59%Vocabulary73%
18wSentence Length15w
0.16Hedging0.18
4.4Bold0.0
3.0Lists2.1
0.00Emoji0.00
0.89Headings0.00
0.11Transitions0.02
Based on 27 + 10 text responses
FAQ
