Nano Banana aspect ratios: every shape and its size
By GetStepSnap · Checked against Google's docs and tested October 8, 2026
Nano Banana 2.1 makes 14 shapes, from an 8:1 banner to a 1:8 strip. Nano Banana Pro makes 10. Below: one prompt we ran in seven shapes, Google's exact pixel sizes, and which model takes which ratio.
One prompt, seven shapes
Each is the first result at 1K, with the size fal.ai returned. The prompt: "A watercolor landscape of rolling green hills, a winding river and a small red barn under a soft morning sky, with a flock of birds in the distance."
Google's table gives 4:1 and 1:4 as 2048 x 512 at 1K; fal.ai returned 2064 x 512. Every other shape matched the table.
Nano Banana 2.1 sizes at 1K, 2K and 4K
| Shape | 1K | 2K | 4K |
|---|---|---|---|
| 1:1 | 1024 x 1024 | 2048 x 2048 | 4096 x 4096 |
| 4:5 | 928 x 1152 | 1856 x 2304 | 3712 x 4608 |
| 5:4 | 1152 x 928 | 2304 x 1856 | 4608 x 3712 |
| 3:4 | 896 x 1200 | 1792 x 2400 | 3584 x 4800 |
| 4:3 | 1200 x 896 | 2400 x 1792 | 4800 x 3584 |
| 2:3 | 848 x 1264 | 1696 x 2528 | 3392 x 5056 |
| 3:2 | 1264 x 848 | 2528 x 1696 | 5056 x 3392 |
| 9:16 | 768 x 1376 | 1536 x 2752 | 3072 x 5504 |
| 16:9 | 1376 x 768 | 2752 x 1536 | 5504 x 3072 |
| 21:9 | 1584 x 672 | 3168 x 1344 | 6336 x 2688 |
| 1:4 | 512 x 2048 | 1024 x 4096 | 2048 x 8192 |
| 4:1 | 2048 x 512 | 4096 x 1024 | 8192 x 2048 |
| 1:8 | 384 x 3072 | 768 x 6144 | 1536 x 12288 |
| 8:1 | 3072 x 384 | 6144 x 768 | 12288 x 1536 |
Source: Gemini API image generation docs, checked October 8, 2026.
Which model takes which ratio
- Nano Banana 2.1: 14 ratios (1:1, 2:3, 3:2, 3:4, 4:3, 4:5, 5:4, 9:16, 16:9, 21:9, 1:4, 4:1, 1:8, 8:1), 1K, 2K and 4K.
- Nano Banana 2: 14 ratios (1:1, 2:3, 3:2, 3:4, 4:3, 4:5, 5:4, 9:16, 16:9, 21:9, 1:4, 4:1, 1:8, 8:1), also a 512 px size.
- Nano Banana Pro: 10 ratios (1:1, 2:3, 3:2, 3:4, 4:3, 4:5, 5:4, 9:16, 16:9, 21:9), 1K, 2K and 4K.
- Nano Banana 2 Lite: 10 ratios (1:1, 2:3, 3:2, 3:4, 4:3, 4:5, 5:4, 9:16, 16:9, 21:9).
- Nano Banana (the first): 10 ratios (1:1, 2:3, 3:2, 3:4, 4:3, 4:5, 5:4, 9:16, 16:9, 21:9), about 1K only.
In the Gemini app, Google's help page for making images doesn't list an aspect ratio setting. On GetStepSnap the Nano Banana 2.1 tool offers all 14, plus Auto, which leaves the shape to the model.
Which shape for what
- 16:9 for YouTube thumbnails, which YouTube asks for (see our thumbnail prompts).
- 9:16 to fill a phone screen.
- 4:5 and 3:4 for portraits.
- 4:1, 21:9 and 8:1 for banners and headers.
What it costs
On GetStepSnap your first 1K image is free. After that every shape takes 1 credit at 1K or 2K and 3 credits at 4K, and 100 credits cost $9.90 (plus local tax where it applies). Ours took 15 to 17 seconds each. Try Nano Banana 2.1.
Questions
What aspect ratios does Nano Banana support?
Nano Banana 2.1 and Nano Banana 2 take 14: 1:1, 4:5, 5:4, 3:4, 4:3, 2:3, 3:2, 9:16, 16:9, 21:9, 1:4, 4:1, 1:8 and 8:1. Nano Banana Pro, 2 Lite and the first Nano Banana take the first 10 (Google's Gemini API docs, checked October 8, 2026).
What size is a 16:9 Nano Banana 2.1 image?
1376 x 768 at 1K, 2752 x 1536 at 2K and 5504 x 3072 at 4K, by Google's table. Our 1K test came back at 1376 x 768.
Does Nano Banana Pro make 4:1 or 8:1 images?
No. Google's docs list 10 ratios for Pro, from 21:9 to 9:16. The very wide and very tall ones (4:1, 1:4, 8:1, 1:8) are for Nano Banana 2 and 2.1.
Can I pick the aspect ratio in the Gemini app?
Google's help page for making images in the Gemini app doesn't list an aspect ratio setting (checked October 8, 2026). Through the API, and on GetStepSnap, you choose one of 14 before you generate.
Does a wider image cost more?
Not on GetStepSnap: every shape takes 1 credit at 1K or 2K and 3 credits at 4K. Google's own table bills each 1K image the same number of tokens whatever the shape.