Prices → Compare → GPT-5.3 Codex vs Gemini 3.7 Flash
GPT-5.3 Codex vs Gemini 3.7 Flash: API cost compared
GPT-5.3 Codex lists at $1.750 in / $14.00 out per 1M tokens. Gemini 3.7 Flash lists at $0.750 in / $3.750. Sticker price only tells you so much — below is what each actually costs across eight production workloads.
Side by side
| GPT-5.3 Codex | Gemini 3.7 Flash | |
|---|---|---|
| Provider | OpenAI | |
| Input per 1M | $1.750 | $0.750 |
| Output per 1M | $14.00 | $3.750 |
| Cached input per 1M | $0.175 | not published |
| Context window | 400k | 1M |
| Blended per 1M (3:1) | $4.812 | $1.500 |
Monthly cost by workload
Caching applied at each workload's typical hit rate. This is where the two models actually separate.
| Workload | GPT-5.3 Codex | Gemini 3.7 Flash | Cheaper | Difference |
|---|---|---|---|---|
| Customer support chatbot | $317.45 | $133.12 | Gemini 3.7 Flash | $184.32 (58%) |
| RAG document Q&A | $385.00 | $165.00 | Gemini 3.7 Flash | $220.00 (57%) |
| Coding agent | $224.88 | $120.00 | Gemini 3.7 Flash | $104.88 (47%) |
| Bulk summarization | $2,566 | $1,050 | Gemini 3.7 Flash | $1,516 (59%) |
| Structured data extraction | $3,710 | $1,781 | Gemini 3.7 Flash | $1,929 (52%) |
| Long-form content generation | $585.55 | $165.00 | Gemini 3.7 Flash | $420.55 (72%) |
| Email triage agent | $861.87 | $487.50 | Gemini 3.7 Flash | $374.37 (43%) |
| Translation pipeline | $3,718 | $1,069 | Gemini 3.7 Flash | $2,650 (71%) |
How to read this
Gemini 3.7 Flash is cheaper on the majority of these workloads, but "majority" is not the decision. The output:input price ratio is 8.0 for GPT-5.3 Codex and 5.0 for Gemini 3.7 Flash. If your traffic is output-heavy — long-form drafting, translation — the model with the lower output price wins regardless of what the input price suggests. If you are input-heavy — RAG, bulk summarization, agents re-reading a codebase — the cached input rate matters more than either headline number.
Cost is also not the only axis. This site does not benchmark quality, latency, or rate limits, and a model that is 3x cheaper but needs two attempts per task is not cheaper. Use these numbers to size a bill, then validate on your own evals.
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| Model | In /1M | Out /1M | Monthly | vs best |
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