GPT-5.3-Codex is $28.25 cheaper per 1M input tokens (94.2% lower; 17.1x difference).
API cost decision in 10 seconds
GPT-5.3-Codex vs GPT-5.5 Pro
Pick GPT-5.3-Codex for lower cost; pick GPT-5.5 Pro only if the larger context window matters more.
Page updated:
Data confirmed:
Prices normalized to USD per 1M tokens
Sample workload: 1M input + 500K output
Budget verdict
Pick GPT-5.3-Codex for lower cost; pick GPT-5.5 Pro only if the larger context window matters more.
On the standard 1M input plus 500K output workload, GPT-5.3-Codex is estimated at $8.75 vs $120 for GPT-5.5 Pro, saving $111.25 (92.7% lower).
Cost-first pickGPT-5.3-Codex
Context-first pickGPT-5.5 Pro
Sample savings$111.2592.7%
10x traffic gap$1112.5
GPT-5.5 Pro has more context, but GPT-5.3-Codex saves $111.25 on the standard workload. At 10x that traffic, the same price gap is about $1112.5. Use the calculator below to replace the sample workload with your own token volume.
Cost sensitivity
Workload Sensitivity
GPT-5.3-Codex stays cheaper across input-heavy, balanced, and output-heavy sample workloads.
| Workload shape | Token mix | Better pick | GPT-5.3-Codex | GPT-5.5 Pro |
|---|---|---|---|---|
| Input-heavy / RAG | 5M input + 500K output | GPT-5.3-Codex | $15.75 | $240 |
| Balanced workload | 1M input + 1M output | GPT-5.3-Codex | $15.75 | $210 |
| Output-heavy chatbot | 1M input + 5M output | GPT-5.3-Codex | $71.75 | $930 |
GPT-5.3-Codex is $166 cheaper per 1M output tokens (92.2% lower; 12.9x difference).
GPT-5.5 Pro has 650K more context (2.62x larger).
GPT-5.3-Codex is $111.25 cheaper on the standard workload (92.7% lower).
Estimate your workload cost
Your Workload Cost
This estimate uses normalized public API pricing per 1M tokens. It is a planning aid, not a billing quote. Verify provider pricing, limits, and terms before production use.
Quick Decision
GPT-5.3-Codex has the lower input price; GPT-5.3-Codex has the lower output price; GPT-5.5 Pro offers the larger context window. For the 1M input plus 500K output sample, GPT-5.3-Codex is cheaper for the standard workload.
For a 1M input token plus 500K output token workload, the estimated API cost is $8.75 for GPT-5.3-Codex and $120 for GPT-5.5 Pro.
Choose GPT-5.3-Codex when you care most about lower input-token price, and lower output-token price.
Choose GPT-5.5 Pro when you care most about larger context window.
- On the standard 1M input plus 500K output workload, GPT-5.3-Codex is estimated at $8.75 vs $120 for GPT-5.5 Pro, saving $111.25 (92.7% lower).
- GPT-5.3-Codex is $111.25 cheaper on the standard workload (92.7% lower).
- GPT-5.3-Codex is $28.25 cheaper per 1M input tokens (94.2% lower; 17.1x difference).
- GPT-5.3-Codex is $166 cheaper per 1M output tokens (92.2% lower; 12.9x difference).
- GPT-5.5 Pro has 650K more context (2.62x larger).
| Feature | GPT-5.3-Codex (OpenAI) | GPT-5.5 Pro (OpenAI) |
|---|---|---|
| Input Price prompt tokens per 1M | $1.75 | $30 |
| Completion Price per 1M tokens | $14 | $180 |
| Sample Workload Cost 1M input + 500K output | $8.75 | $120 |
| Context Window | 400K | 1.05M |
| Release Date | ||
| Popularity | #44 | #122 |
Use-Case Decision Matrix
| Use case | Better pick | Why |
|---|---|---|
| Budget-constrained production | GPT-5.3-Codex | On the standard 1M input plus 500K output workload, GPT-5.3-Codex is estimated at $8.75 vs $120 for GPT-5.5 Pro, saving $111.25 (92.7% lower). |
| High-volume input processing | GPT-5.3-Codex | Lower prompt-token price matters most when prompts, retrieved passages, or documents dominate the bill. |
| Long responses and chatbots | GPT-5.3-Codex | Lower output-token price matters most when assistants generate many completion tokens. |
| RAG or long-document work | GPT-5.5 Pro | A larger context window leaves more room for retrieved passages, conversation history, or source files. |
Related Alternatives
- gpt-oss-120b (free) can replace GPT-5.3-Codex when lower sample workload cost matters most: $0.
- gpt-oss-20b (free) can replace GPT-5.3-Codex when lower sample workload cost matters most: $0.
- gpt-oss-20b can replace GPT-5.3-Codex when lower sample workload cost matters most: $0.1.
- gpt-oss-120b can replace GPT-5.3-Codex when lower sample workload cost matters most: $0.13.
- Llama 4 Scout offers 10M context with $0.23 sample workload cost.
- Grok 4.20 offers 2M context with $2.5 sample workload cost.
- Grok 4.20 Multi-Agent offers 2M context with $5 sample workload cost.
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