Llama 3.1 405B vs OpenAI o3
Compare Llama 3.1 405B by Meta AI against OpenAI o3 by OpenAI, tested across 12 shared challenges. Updated May 2026.
Which is better, Llama 3.1 405B or OpenAI o3?
Llama 3.1 405B and OpenAI o3 are both competitive models. Llama 3.1 405B costs $2.7/M input tokens vs $10/M for OpenAI o3. Compare their real outputs side by side below.
Key Differences Between Llama 3.1 405B and OpenAI o3
Llama 3.1 405B is made by meta while OpenAI o3 is from openai. On pricing, Llama 3.1 405B costs $2.7/M input tokens vs $10/M for OpenAI o3.
API pricing
Per 1M tokens
Llama 3.1 405B
Input
$2.70
3.7× cheaper
Output
$3.10
13× cheaper
OpenAI o3
Input
$10.00
Output
$40.00
Llama 3.1 405B is cheaper on both — 3.7× input, 13× output
Our Verdict
Llama 3.1 405B
OpenAI o3
No community votes yet. On paper, these are closely matched - try both with your actual task to see which fits your workflow.
Llama 3.1 405B is 13x cheaper per token — worth considering if cost matters.
Too close to call
Writing DNA
Style Comparison
Similarity
49%
OpenAI o3 uses 69.5x more bold
Llama 3.1 405B
OpenAI o3
56%Vocabulary68%
15wSentence Length14w
0.41Hedging0.26
0.0Bold0.7
1.9Lists3.0
0.03Emoji0.00
0.00Headings0.38
0.16Transitions0.12
Based on 5 + 16 text responses
FAQ
