GPT-5.1 Chat is $0.75 cheaper per 1M input tokens (37.5% lower; 1.6x difference).
API cost decision in 10 seconds
Nano Banana Pro (Gemini 3 Pro Image Preview) vs GPT-5.1 Chat
Pick GPT-5.1 Chat when budget and context both matter.
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Data confirmed:
Prices normalized to USD per 1M tokens
Sample workload: 1M input + 500K output
Budget verdict
Pick GPT-5.1 Chat when budget and context both matter.
On the standard 1M input plus 500K output workload, GPT-5.1 Chat is estimated at $6.25 vs $8 for Nano Banana Pro (Gemini 3 Pro Image Preview), saving $1.75 (21.9% lower).
Cost-first pickGPT-5.1 Chat
Context-first pickGPT-5.1 Chat
Sample savings$1.7521.9%
10x traffic gap$17.5
GPT-5.1 Chat is cheaper on the standard workload and also has the larger context window. At 10x that traffic, the same price gap is about $17.5. Use the calculator below to replace the sample workload with your own token volume.
Cost sensitivity
Workload Sensitivity
GPT-5.1 Chat stays cheaper across input-heavy, balanced, and output-heavy sample workloads.
| Workload shape | Token mix | Better pick | Nano Banana Pro (Gemini 3 Pro Image Preview) | GPT-5.1 Chat |
|---|---|---|---|---|
| Input-heavy / RAG | 5M input + 500K output | GPT-5.1 Chat | $16 | $11.25 |
| Balanced workload | 1M input + 1M output | GPT-5.1 Chat | $14 | $11.25 |
| Output-heavy chatbot | 1M input + 5M output | GPT-5.1 Chat | $62 | $51.25 |
GPT-5.1 Chat is $2 cheaper per 1M output tokens (16.7% lower; 1.2x difference).
GPT-5.1 Chat has 62.46K more context (1.95x larger).
GPT-5.1 Chat is $1.75 cheaper on the standard workload (21.9% 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-5.1 Chat has the lower input price; GPT-5.1 Chat has the lower output price; GPT-5.1 Chat offers the larger context window. For the 1M input plus 500K output sample, GPT-5.1 Chat is cheaper for the standard workload.
For a 1M input token plus 500K output token workload, the estimated API cost is $8 for Nano Banana Pro (Gemini 3 Pro Image Preview) and $6.25 for GPT-5.1 Chat.
Choose Nano Banana Pro (Gemini 3 Pro Image Preview) when its provider, model quality, latency, or availability is more important than the numeric price/context winner.
Choose GPT-5.1 Chat when you care most about lower input-token price, lower output-token price, and larger context window.
- On the standard 1M input plus 500K output workload, GPT-5.1 Chat is estimated at $6.25 vs $8 for Nano Banana Pro (Gemini 3 Pro Image Preview), saving $1.75 (21.9% lower).
- GPT-5.1 Chat is $1.75 cheaper on the standard workload (21.9% lower).
- GPT-5.1 Chat is $0.75 cheaper per 1M input tokens (37.5% lower; 1.6x difference).
- GPT-5.1 Chat is $2 cheaper per 1M output tokens (16.7% lower; 1.2x difference).
- GPT-5.1 Chat has 62.46K more context (1.95x larger).
| Feature | Nano Banana Pro (Gemini 3 Pro Image Preview) (Google) | GPT-5.1 Chat (OpenAI) |
|---|---|---|
| Input Price prompt tokens per 1M | $2 | $1.25 |
| Completion Price per 1M tokens | $12 | $10 |
| Sample Workload Cost 1M input + 500K output | $8 | $6.25 |
| Context Window | 65.54K | 128K |
| Release Date |
Use-Case Decision Matrix
| Use case | Better pick | Why |
|---|---|---|
| Budget-constrained production | GPT-5.1 Chat | On the standard 1M input plus 500K output workload, GPT-5.1 Chat is estimated at $6.25 vs $8 for Nano Banana Pro (Gemini 3 Pro Image Preview), saving $1.75 (21.9% lower). |
| High-volume input processing | GPT-5.1 Chat | Lower prompt-token price matters most when prompts, retrieved passages, or documents dominate the bill. |
| Long responses and chatbots | GPT-5.1 Chat | Lower output-token price matters most when assistants generate many completion tokens. |
| RAG or long-document work | GPT-5.1 Chat | A larger context window leaves more room for retrieved passages, conversation history, or source files. |
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