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OpenAI: GPT-5 Codex vs Google: Gemini 3 Flash Preview

Head-to-head API cost, context, and performance comparison. Synced at 11:15:20 AM.

Executive Summary

When evaluating OpenAI: GPT-5 Codex against Google: Gemini 3 Flash Preview, the pricing structure is a key differentiator. Google: Gemini 3 Flash Preview is approximately 69% more cost-effective per 1 million tokens overall.

However, when looking at raw reasoning capabilities, Google: Gemini 3 Flash Preview leads with a statistical ELO score of 1300. For tasks involving complex logic, coding, or instruction-following, developers might prefer Google: Gemini 3 Flash Preview, provided their budget allows for the API burn rate.

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Raw Technical comparison

Metric
OpenAI: GPT-5 Codex
Google: Gemini 3 Flash Preview
Performance (ELO)
1300
1300
Input Cost / 1M
$1.25
$0.50
Output Cost / 1M
$10.00
$3.00
Context Window
400,000 tokens
1,048,576 tokens

Verdict

If you are looking for pure performance and capability, Tie is statistically superior. However, if API burn rate is the primary concern, Google: Gemini 3 Flash Preview wins out aggressively in pricing.

People Also Ask

Is OpenAI: GPT-5 Codex cheaper than Google: Gemini 3 Flash Preview?

No. Google: Gemini 3 Flash Preview is the more cost-effective model, operating at a lower price point per 1 million tokens.

Which model has the larger context window?

The Google: Gemini 3 Flash Preview model has the advantage in memory, offering a massive 1,048,576 token limit for document ingestion.

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