Imagen 4 Fast vs Nano Banana 2
Google's Imagen 4 Fast and Google's Nano Banana 2 both target image generation, but they price and behave differently. Here is the side-by-side.
Pricing checked against provider documentation on . How we verify
The short answer
Imagen 4 Fast is the cheaper option — roughly 3.4x less on a blended workload, and it suits cheapest speed-first generation. Nano Banana 2 justifies its premium when you need fast generation with multilingual text.
Google • Imagen 4
$0.02 / $
/ image (input / output)
Google's efficiency tier for image generation, aimed at high-volume pipelines where throughput matters more than the last increment of quality. Fine for thumbnails, placeholders, and drafts; step up to the Gemini image models when typography or compositing is the point.
Google • Gemini Image
$0.07 / $
/ image (input / output)
Renders in roughly 1.4 seconds and handles text in over 30 languages including non-Latin scripts, which is unusual. Google bills it by output tokens rather than per image, so the price scales with resolution — a 4K render costs more than three times a 512px one.
Input price
Nano Banana 2 is 3.4x the price than Imagen 4 Fast on input tokens.
Specification comparison
| Attribute | Imagen 4 Fast | Nano Banana 2 |
|---|---|---|
| Input (/ image) | $0.02 | $0.07 |
| Output (/ image) | — | — |
| Cached input | — | — |
| Context window | — | — |
| Max output | — | — |
| Native reasoning | No | No |
| Knowledge cutoff | — | — |
| Relative latency | low | low |
| Open weights | No | No |
| API model ID | imagen-4.0-fast-generate-001 | gemini-3.1-flash-image |
| Status | stable | stable |
Imagen 4 Fast: 1K resolution.
Nano Banana 2: 1024² render. Priced at $60 per million output tokens, so cost tracks resolution: $0.045 at 512px, $0.067 at 1K, $0.101 at 2K, $0.151 at 4K. Batch mode halves all of these.
Choose Imagen 4 Fast if…
- High-volume thumbnails
- Draft and placeholder imagery
- Rapid prompt iteration
- Catalogue and listing images
Choose Nano Banana 2 if…
- Interactive generation in product UIs
- Non-Latin script text in images
- Rapid creative iteration
- Image editing and compositing
Frequently asked
Is Imagen 4 Fast or Nano Banana 2 cheaper?
Imagen 4 Fast is cheaper. On a blended 3:1 input-to-output workload it costs about 3.4x less than Nano Banana 2.
Which has the larger context window, Imagen 4 Fast or Nano Banana 2?
Both accept up to — tokens, so context is not a differentiator here.
Should I use Imagen 4 Fast or Nano Banana 2?
Pick Imagen 4 Fast for cheapest speed-first generation. Pick Nano Banana 2 for fast generation with multilingual text. If cost dominates the decision, Imagen 4 Fast wins; if you need the capability ceiling, benchmark both on your own evals before committing.