OpenAI: GPT-5.3-Codex vs OpenAI: o3
Head-to-head API cost, context, and performance comparison. Synced at 9:50:09 AM.
Executive Summary
When evaluating OpenAI: GPT-5.3-Codex against OpenAI: o3, the pricing structure is a key differentiator. OpenAI: o3 is approximately 37% more cost-effective per 1 million tokens overall.
However, when looking at raw reasoning capabilities, OpenAI: GPT-5.3-Codex leads with a statistical ELO score of 1410. For tasks involving complex logic, coding, or instruction-following, developers might prefer OpenAI: GPT-5.3-Codex, provided their budget allows for the API burn rate.
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Raw Technical comparison
Verdict
If you are looking for pure performance and capability, OpenAI: GPT-5.3-Codex is statistically superior. However, if API burn rate is the primary concern, OpenAI: o3 wins out aggressively in pricing.
People Also Ask
Is OpenAI: GPT-5.3-Codex cheaper than OpenAI: o3?
No. OpenAI: o3 is the more cost-effective model, operating at a lower price point per 1 million tokens.
Which model has the larger context window?
The OpenAI: GPT-5.3-Codex model has the advantage in memory, offering a massive 400,000 token limit for document ingestion.