Prices → Compare → GPT-5.6 Sol vs GPT-5.3 Codex
GPT-5.6 Sol vs GPT-5.3 Codex: API cost compared
GPT-5.6 Sol lists at $2.500 in / $15.00 out per 1M tokens. GPT-5.3 Codex lists at $1.750 in / $14.00. Sticker price only tells you so much — below is what each actually costs across eight production workloads.
Side by side
| GPT-5.6 Sol | GPT-5.3 Codex | |
|---|---|---|
| Provider | OpenAI | OpenAI |
| Input per 1M | $2.500 | $1.750 |
| Output per 1M | $15.00 | $14.00 |
| Cached input per 1M | $0.250 | $0.175 |
| Context window | 400k | 400k |
| Blended per 1M (3:1) | $5.625 | $4.812 |
Monthly cost by workload
Caching applied at each workload's typical hit rate. This is where the two models actually separate.
| Workload | GPT-5.6 Sol | GPT-5.3 Codex | Cheaper | Difference |
|---|---|---|---|---|
| Customer support chatbot | $366.00 | $317.45 | GPT-5.3 Codex | $48.55 (13%) |
| RAG document Q&A | $490.00 | $385.00 | GPT-5.3 Codex | $105.00 (21%) |
| Coding agent | $261.25 | $224.88 | GPT-5.3 Codex | $36.37 (14%) |
| Bulk summarization | $3,465 | $2,566 | GPT-5.3 Codex | $899.50 (26%) |
| Structured data extraction | $4,675 | $3,710 | GPT-5.3 Codex | $965.00 (21%) |
| Long-form content generation | $636.50 | $585.55 | GPT-5.3 Codex | $50.95 (8%) |
| Email triage agent | $1,081 | $861.87 | GPT-5.3 Codex | $219.38 (20%) |
| Translation pipeline | $4,112 | $3,718 | GPT-5.3 Codex | $393.56 (10%) |
How to read this
GPT-5.3 Codex is cheaper on the majority of these workloads, but "majority" is not the decision. The output:input price ratio is 6.0 for GPT-5.6 Sol and 8.0 for GPT-5.3 Codex. 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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