GPT-5.3 Chat is $0.25 cheaper per 1M input tokens (12.5% lower; 1.14x difference).
API cost decision in 10 seconds
GPT-5.3 Chat vs Gemini 3.1 Pro Preview Custom Tools
Pick Gemini 3.1 Pro Preview Custom Tools when budget and context both matter.
Pricing data updated:
Prices normalized to USD per 1M tokens
Sample workload: 1M input + 500K output
Budget verdict
Pick Gemini 3.1 Pro Preview Custom Tools when budget and context both matter.
On the standard 1M input plus 500K output workload, Gemini 3.1 Pro Preview Custom Tools is estimated at $8 vs $8.75 for GPT-5.3 Chat, saving $0.75 (8.6% lower).
Cost-first pickGemini 3.1 Pro Preview Custom Tools
Context-first pickGemini 3.1 Pro Preview Custom Tools
Sample savings$0.758.6%
10x traffic gap$7.5
Gemini 3.1 Pro Preview Custom Tools is cheaper on the standard workload and also has the larger context window. At 10x that traffic, the same price gap is about $7.5. Use the calculator below to replace the sample workload with your own token volume.
Cost sensitivity
Workload Sensitivity
Cost winner changes by workload shape: input-heavy / RAG favors GPT-5.3 Chat, balanced workload favors Gemini 3.1 Pro Preview Custom Tools, and output-heavy chatbot favors Gemini 3.1 Pro Preview Custom Tools.
| Workload shape | Token mix | Better pick | GPT-5.3 Chat | Gemini 3.1 Pro Preview Custom Tools |
|---|---|---|---|---|
| Input-heavy / RAG | 5M input + 500K output | GPT-5.3 Chat | $15.75 | $16 |
| Balanced workload | 1M input + 1M output | Gemini 3.1 Pro Preview Custom Tools | $15.75 | $14 |
| Output-heavy chatbot | 1M input + 5M output | Gemini 3.1 Pro Preview Custom Tools | $71.75 | $62 |
Gemini 3.1 Pro Preview Custom Tools is $2 cheaper per 1M output tokens (14.3% lower; 1.17x difference).
Gemini 3.1 Pro Preview Custom Tools has 920.76K more context (8.19x larger).
Gemini 3.1 Pro Preview Custom Tools is $0.75 cheaper on the standard workload (8.6% 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 Chat has the lower input price; Gemini 3.1 Pro Preview Custom Tools has the lower output price; Gemini 3.1 Pro Preview Custom Tools offers the larger context window. For the 1M input plus 500K output sample, Gemini 3.1 Pro Preview Custom Tools 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 Chat and $8 for Gemini 3.1 Pro Preview Custom Tools.
Choose GPT-5.3 Chat when you care most about lower input-token price.
Choose Gemini 3.1 Pro Preview Custom Tools when you care most about lower output-token price, and larger context window.
- On the standard 1M input plus 500K output workload, Gemini 3.1 Pro Preview Custom Tools is estimated at $8 vs $8.75 for GPT-5.3 Chat, saving $0.75 (8.6% lower).
- Gemini 3.1 Pro Preview Custom Tools is $0.75 cheaper on the standard workload (8.6% lower).
- GPT-5.3 Chat is $0.25 cheaper per 1M input tokens (12.5% lower; 1.14x difference).
- Gemini 3.1 Pro Preview Custom Tools is $2 cheaper per 1M output tokens (14.3% lower; 1.17x difference).
- Gemini 3.1 Pro Preview Custom Tools has 920.76K more context (8.19x larger).
| Feature | GPT-5.3 Chat (OpenAI) | Gemini 3.1 Pro Preview Custom Tools (Google) |
|---|---|---|
| Input Price prompt tokens per 1M | $1.75 | $2 |
| Completion Price per 1M tokens | $14 | $12 |
| Sample Workload Cost 1M input + 500K output | $8.75 | $8 |
| Context Window | 128K | 1.05M |
| Release Date |
Use-Case Decision Matrix
| Use case | Better pick | Why |
|---|---|---|
| Budget-constrained production | Gemini 3.1 Pro Preview Custom Tools | On the standard 1M input plus 500K output workload, Gemini 3.1 Pro Preview Custom Tools is estimated at $8 vs $8.75 for GPT-5.3 Chat, saving $0.75 (8.6% lower). |
| High-volume input processing | GPT-5.3 Chat | Lower prompt-token price matters most when prompts, retrieved passages, or documents dominate the bill. |
| Long responses and chatbots | Gemini 3.1 Pro Preview Custom Tools | Lower output-token price matters most when assistants generate many completion tokens. |
| RAG or long-document work | Gemini 3.1 Pro Preview Custom Tools | 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 Chat when lower sample workload cost matters most: $0.
- gpt-oss-20b (free) can replace GPT-5.3 Chat when lower sample workload cost matters most: $0.
- gpt-oss-20b can replace GPT-5.3 Chat when lower sample workload cost matters most: $0.1.
- gpt-oss-120b can replace GPT-5.3 Chat when lower sample workload cost matters most: $0.13.
- Llama 4 Scout offers 10M context with $0.23 sample workload cost.
- Grok 4.20 Multi-Agent offers 2M context with $5 sample workload cost.
- Grok 4.20 offers 2M context with $2.5 sample workload cost.
- GPT-5.4 offers 1.05M context with $10 sample workload cost.
- No popular competitor is currently available.
Cheaper alternatives
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