GPT-5 mini vs Nano Banana 2 (Gemini 3.1 Flash Image): API Cost Comparison
Compare the API pricing, context windows, features, and real-world cost projections for GPT-5 mini (OpenAI) and Nano Banana 2 (Gemini 3.1 Flash Image) (Google). Use the interactive calculator below to compute your exact monthly cost based on your token usage and request volume.
Prices verified Jun 26, 2026
Interactive Cost Calculator
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Showing costs for 2 models. Cheapest: GPT-5 mini at $12.50/month.
| Alert | |||||||
|---|---|---|---|---|---|---|---|
BestGPT-5 mini | OpenAI | $12.50 | $0.001250 | $2.50 | $10.00 | 37.5% | Alerts coming soon |
Nano Banana 2 (Gemini 3.1 Flash Image) | $20.00 | $0.002000 | $5.00 | $15.00 | — | Alerts coming soon |
Monthly Cost Comparison
Price Comparison at a Glance
All prices are in USD per 1 million tokens ($/M tokens). Lower is cheaper.
| Pricing Type | GPT-5 mini | Nano Banana 2 (Gemini 3.1 Flash Image) | Cheaper |
|---|---|---|---|
| Input (standard) | $0.25/M | $0.50/M | GPT-5 mini |
| Output | $2.00/M | $3.00/M | GPT-5 mini |
| Cached input | $0.03/M | N/A | — |
Prices last verified: 2026-03-08 – 2026-06-26
Cost Breakdown by Usage Volume
Estimated monthly costs at different request volumes, assuming 1,000 input tokens and 500 output tokens per request. Adjust in the calculator above for your specific use case.
| Volume | GPT-5 miniMonthly | Nano Banana 2 (Gemini 3.1 Flash Image)Monthly | GPT-5 miniPer request | Nano Banana 2 (Gemini 3.1 Flash Image)Per request |
|---|---|---|---|---|
| 1K requests/mo | $1.25 | $2.00 | $0.001250 | $0.002000 |
| 10K requests/mo | $12.50 | $20.00 | $0.001250 | $0.002000 |
| 100K requests/mo | $125.00 | $200.00 | $0.001250 | $0.002000 |
| 1M requests/mo | $1,250.00 | $2,000.00 | $0.001250 | $0.002000 |
Green values indicate the lower-cost option at each volume tier. Cost per request is calculated at 1,000 input + 500 output tokens using standard (non-batch, non-cached) pricing.
Price History
Input price per 1M tokensWhen to Choose GPT-5 mini
by OpenAI
- Customer support
- General chatbot
- Data extraction
Input / 1M tokens
$0.25/M
Output / 1M tokens
$2.00/M
Context window
400,000
Tier
mid
When to Choose Nano Banana 2 (Gemini 3.1 Flash Image)
by Google
- General chatbot
Input / 1M tokens
$0.50/M
Output / 1M tokens
$3.00/M
Context window
131,072
Tier
budget
Key Differences Beyond Price
Cost is only one factor in choosing an AI model. Context window size, rate limits, supported features, and latency all affect whether a model fits your use case.
| Capability | GPT-5 mini | Nano Banana 2 (Gemini 3.1 Flash Image) |
|---|---|---|
| Context window | 400,000 tokens | 131,072 tokens |
| Max output tokens | 128,000 tokens | 32,768 tokens |
| Performance tier | Mid | Budget |
| Vision / image input | Yes | Yes |
| Function calling | Yes | No |
| JSON mode | Yes | Yes |
| Prompt caching | Yes | No |
| Batch API (50% discount) | No | No |
| Extended reasoning | No | Yes |
| Fine-tuning | No | No |
| Rate limit (req/min) | 10,000 | Not published |
GPT-5 mini notes
1M context window at mid-tier pricing. Good balance of cost and capability.
Frequently Asked Questions
Is GPT-5 mini cheaper than Nano Banana 2 (Gemini 3.1 Flash Image)?
At standard usage (1,000 input tokens, 500 output tokens, 100,000 requests/month), GPT-5 mini costs $125.00/month versus $200.00/month for Nano Banana 2 (Gemini 3.1 Flash Image) — a 38% saving. Your actual savings will vary based on your token profile; output-heavy workloads amplify differences in output pricing.
Which model has a larger context window, GPT-5 mini or Nano Banana 2 (Gemini 3.1 Flash Image)?
GPT-5 mini has a larger context window at 400,000 tokens, compared to 131,072 tokens for Nano Banana 2 (Gemini 3.1 Flash Image). A larger context window is important for processing long documents, multi-turn conversations, or large codebases without truncation.
Do GPT-5 mini and Nano Banana 2 (Gemini 3.1 Flash Image) support the Batch API?
Neither GPT-5 mini nor Nano Banana 2 (Gemini 3.1 Flash Image) currently supports a batch API with discounted pricing. For batch-eligible alternatives, consider models from OpenAI, Anthropic, or Google that include batch API support.
Which model offers better prompt caching?
GPT-5 mini supports prompt caching at $0.03/M for cached input, while Nano Banana 2 (Gemini 3.1 Flash Image) does not offer prompt caching. For RAG applications or chatbots with large, repeated context, GPT-5 mini's caching capability can substantially reduce effective costs.
What are the best use cases for GPT-5 mini vs Nano Banana 2 (Gemini 3.1 Flash Image)?
Both models are well-suited for General chatbot. GPT-5 mini is particularly strong for Customer support, Data extraction. Nano Banana 2 (Gemini 3.1 Flash Image) is favored for similar workflows. At the same quality level, the lower-cost model is usually preferable; use this page's calculator to compare total monthly spend at your volume.
What is the cost per request for GPT-5 mini vs Nano Banana 2 (Gemini 3.1 Flash Image)?
At 1,000 input tokens and 500 output tokens per request — a typical conversational workload — GPT-5 mini costs $0.001250 per request and Nano Banana 2 (Gemini 3.1 Flash Image) costs $0.002000 per request. At 100,000 requests/month, that translates to $125.00 and $200.00 respectively. Use the interactive calculator to adjust these parameters for your actual workload.
GPT-5 mini vs Nano Banana 2 (Gemini 3.1 Flash Image): Summary
When comparing GPT-5 mini and Nano Banana 2 (Gemini 3.1 Flash Image) for API cost, the right choice depends on your workload's token profile, required features, and tolerance for latency. GPT-5 mini offers lower total cost at standard usage volumes (1,000 input + 500 output tokens per request at 100,000 requests/month) at $125.00/month, compared to $200.00/month for Nano Banana 2 (Gemini 3.1 Flash Image).
Both models are priced in USD per million tokens, the standard unit across all major AI API providers. GPT-5 mini charges $0.25/M for input tokens and $2.00/M for output tokens. Nano Banana 2 (Gemini 3.1 Flash Image) charges $0.50/M input and $3.00/M output. If your workload is output-heavy (more tokens generated than consumed as input), the model with the lower output price compounds cost savings significantly at scale.
Prompt caching is supported by GPT-5 mini but not Nano Banana 2 (Gemini 3.1 Flash Image). For workloads with large, repeated system prompts or document context — such as RAG pipelines or multi-turn conversations with a fixed knowledge base — prompt caching can reduce effective input costs by 60–90%, which may change the cost ranking between these two models at your specific usage pattern.
Context window capacity differs between the two: GPT-5 mini supports up to 400,000 tokens in a single request, versus 131,072 tokens for Nano Banana 2 (Gemini 3.1 Flash Image). A larger context window is essential for document summarization, large codebase analysis, and multi-document retrieval-augmented generation (RAG) applications.
Use the interactive calculator at the top of this page to enter your actual token usage and monthly request volume for a precise cost comparison tailored to your workload. Adjust for batch API discounts and prompt caching to find the most cost-effective option for your specific deployment.
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Relevant Use Cases
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