Nano Banana Pro pricing [2026 edition] — API cost per image and how to choose among 5 models

When using Nano Banana Pro through the API, you pay per image. On Kunavo, it starts at $0.067 per image (1K and 2K pricing; 4K costs more). There is no monthly fee, no Google Cloud project is required, and failed requests are not charged. This is a different purchase option from Google's subscription (Google AI Pro / Ultra) for using it in the Gemini app. With the same key, you can choose from five models, including Nano Banana 2 Lite at $0.0255 per image.

Search results for “nano banana pro pricing” mostly explain how to use it in the Gemini app and how many times you can use it on each plan. What they leave out is how much it costs to pay per image through the API, what each of the five models is best suited for, and what kinds of images are worth paying Pro's per-image rate for. This page fills in those three details using the actual catalog figures.

Two ways to pay — a Gemini app subscription or per-image API billing

Google often changes subscription prices and usage limits, so we do not reproduce them here (check Google's official page for the latest terms). You only need one calculation to compare: monthly subscription price ÷ per-image price = break-even number of images. If you use Pro at 1K or 2K, the price is $0.067 per image. In months when you generate fewer images than the monthly fee divided by that amount, API pay-per-image pricing is cheaper; if you generate more but stay within the usage limit, the subscription is cheaper.

There is one more point that is easy to confuse: the subscription and API are billed separately, and subscription usage cannot be applied to API calls. To generate images from code, you need a separate API key and balance.

Per-image pricing for the five Nano Banana models

The prices below are read from the model catalog each time the page is displayed, rather than hard-coded. If prices change, this table will update too and show the same figures as the pricing table and each model page.

Models marked with “+” have prices that vary by output resolution. For Nano Banana Pro, 1K and 2K have the same price, $0.067, while 4K costs more. For Nano Banana 2, 1K costs $0.0469, with the price increasing for 2K and 4K. Choose the resolution with resolution in the request. If omitted, each model uses its default tier. You are charged for the tier actually generated.

Is Pro worth the price? Compare the total cost to finish an image, not just the per-image price

Comparing only per-image prices, Nano Banana Pro costs about 2.6 times as much as Nano Banana 2 Lite, and about 1.4 times as much as Nano Banana 2 (1K). But for image work, what determines the bill is the number of attempts more than the price of a single image. It is common to generate several images while refining the prompt before getting the one you want. Failed requests are not charged, but a successfully generated image you do not like is charged.

For example, suppose you create one finished image with 20 attempts and one final image (calculated using Pro's 1K and 2K prices):

The difference is approximately 59%. There is one caveat: because different models are used for testing and finalizing, the composition is not carried over exactly as it is. What carries over is the prompt. Refine the prompt with the cheaper model, then run Pro just a few times—this sequence minimizes waste.

Images worth paying Pro's per-image price for

• Final images ready to use. Ads, landing page hero images, and images viewed enlarged — cases where the finished image itself is the deliverable.
• Images that contain text. Posters, banners, and infographic headings. For Japanese text in images, it is best to create one image each with Nano Banana Pro and Nano Banana 2 using the same prompt, compare them, and then decide.
• Prompts with many instructions. The more precisely you specify placement, colors, and the number of objects, the more likely you are to see a difference in instruction following.

Images that cheaper models handle well

• Drafts, exploring composition, and prompt iteration
• Thumbnails that will be downscaled or images used in only part of a screen
• Use cases where quantity matters more than the quality of each image (A/B test variations and large batches of variations)

As a rough guide, the minimum $10 top-up can generate about 149 images with Nano Banana Pro (1K and 2K), about 213 with Nano Banana 2 (1K), about 366 with Nano Banana, and about 392 with Nano Banana 2 Lite.

Call the API — keep using the OpenAI SDK; change only base_url and the model name

You can keep using your existing OpenAI SDK. Change the base_url and key in the client initialization, as well as the model name in the request. The endpoint is POST /v1/images/generations and follows the same format as OpenAI's image generation endpoint.

# 既存の OpenAI SDK のまま、base_url とモデル名だけを変えます。
# Google Cloud のプロジェクトも、Google 用の SDK も要りません。
import os
from openai import OpenAI

client = OpenAI(
    base_url="https://api.kunavo.com/v1",
    api_key=os.environ["KUNAVO_API_KEY"],  # sk-kn- で始まるキー
)

img = client.images.generate(
    model="nano-banana-pro",
    prompt="木のテーブルに置いた抹茶ラテ、朝の自然光、商品写真風",
    n=1,
    # resolution は OpenAI SDK の標準の引数にないので extra_body で渡す。
    # Pro は "2K"（1K と同じ料金・既定）か "4K"（高いほうの料金）。
    extra_body={"resolution": "2K"},
)
print(img.data[0].url)  # files.kunavo.com の恒久的な URL

The returned URL is a permanent files.kunavo.com URL and does not expire. For batch processing, you can also add "async": true to the request to receive a task ID and retrieve the result later. The list of parameters is in the Image API documentation, and detailed instructions in English are in the Nano Banana API guide.

Image editing uses a separate endpoint

To edit an existing image, send the source image and instructions to POST /v1/images/edits, an endpoint separate from generation, specifying Nano Banana Edit (nano-banana-edit). Provide the source image as an https URL or a base64 data: URL. The price is $0.0273 per image.

# 画像の編集は、生成とは別のエンドポイント（/v1/images/edits）です。
# 元画像は https の URL か data: の base64 で渡します。
curl -sS https://api.kunavo.com/v1/images/edits \
  -H "Authorization: Bearer $KUNAVO_API_KEY" \
  -H "content-type: application/json" \
  -d '{
    "model": "nano-banana-edit",
    "prompt": "背景だけを夕焼けの空に差し替える",
    "image": "https://example.com/source.png"
  }'

Honestly: cases where this route is not a good fit

The API through the gateway lets you get started with a single key, without a Google account or Cloud project, but uses shared capacity rather than a quota in your own project. There is no dedicated quota or contractual SLA. If you need a guaranteed allocation or SLA at your scale, applying directly to Google may be a better fit. This page does not claim to be a substitute in that case.

Also, if your main use is people creating images one at a time in the Gemini app and your monthly volume stays within the plan's usage limit, a subscription may cost less per image. The API is advantageous when the number of images you generate varies significantly from month to month, or when you generate them automatically from an app or workflow.

Paying from Japan and preventing overspending

You can top up your Kunavo balance at Stripe Checkout with cards including JCB (Visa, Mastercard, American Express, JCB, UnionPay), Apple Pay, Google Pay, and Link. It uses a prepaid wallet model, with a minimum top-up of $10. A $100 top-up gives you $110.00 in balance, $1,000 gives $1,200.00, and $5,000 gives $6,250.00; the balance never expires. Convenience-store payments and PayPay are not supported.

If you integrate image generation into a workflow, it is a good idea to set a monthly spending limit for each key in the key management dashboard first. A key that reaches its limit stops and returns 402, so even if a loop runs out of control, spending on that key is capped at the limit. You can also configure an IP allowlist in the same place. Billing is covered in the Billing documentation, and business operator disclosures are in the Disclosure under the Specified Commercial Transactions Act.

For text model pricing, see Gemini API Pricing and GPT API Pricing; for the differences between Kunavo and official Google keys, see How to Get a Gemini API Key; for video, see How to Use the Seedance API. Model specifications are on the Nano Banana Pro model page.

Frequently asked questions