Nano Banana 2 to 2.1 on Google: 4K falls from $0.151 to $0.113

On Google's own Gemini API price page, Nano Banana 2.1 (gemini-nano-banana-2.1) costs $0.0336 for a 1K image, $0.0504 for 2K and $0.113 for 4K. The older Nano Banana 2 (gemini-3.1-flash-image) lists $0.067, $0.101 and $0.151 at 1K, 2K and 4K. That is about 50 percent less at 1K and 2K and about 25 percent less at 4K. Both figures are Standard-tier prices read on 2026-10-09.

If your code still calls nano-banana-2 on Sume, nothing breaks and nothing is billed at the old model's rate: the Sume Image API docs say google/nano-banana-2 and nano-banana-2 still work and run as Nano Banana 2.1, and the job stores the 2.1 id.

Google's Standard prices, old and new

Output images are priced at $30 per million tokens on the 2.1 card, with 1,120 tokens at 1K, 1,680 at 2K and 3,780 at 4K. The old model's card lists $60 per million image tokens. The change is almost entirely the per-token rate.

What Sume bills for the same tiers

Sume does not pass Google's list price through. Its image rows are provider list price times 1.25, and the Nano Banana 2.1 rows on the Sume price list are $0.075 at 0.5K, $0.10 at 1K, $0.15 at 2K and $0.20 at 4K. These are higher than Google's direct per-image figures at every tier, so a direct Google account is cheaper per image if you only use Nano Banana. Sume is a single wallet and API for other image models, video, audio and utilities.

The Sume docs also say the catalog no longer lists the retired id. A new integration should call google/nano-banana-2.1 or the bare alias nano-banana-2.1 and read supported_parameters from GET /v1/images/models.

• Sume 0.5K: $0.075 (Google lists no 0.5K row on the 2.1 card)
• Sume 1K: $0.10 versus Google $0.0336
• Sume 2K: $0.15 versus Google $0.0504
• Sume 4K: $0.20 versus Google $0.113

What to change in your code

Replace model strings that name Nano Banana 2 with the 2.1 id so logs, dashboards and invoices show the model that actually ran. Keep the 0.5K tier in mind: on Sume it is the cheapest Nano Banana 2.1 row at $0.075, but Google's current 2.1 card lists only 1K, 2K and 4K, so do not assume the tiers match between the two.

A migration example

Suppose an app makes 2,000 4K images a month on Google. On the old Nano Banana 2 card that is 2,000 x $0.151 = $302.00. On the 2.1 card it is 2,000 x $0.113 = $226.00, a saving of $76.00 a month. At 1K the same count goes from 2,000 x $0.067 = $134.00 to 2,000 x $0.0336 = $67.20.

On Sume the same 2,000 4K images are 2,000 x $0.20 = $400.00, whichever of the two ids your code sends, because both run as 2.1. That makes the old id harmless to keep for a while, though the cost line in your own reporting should use the 2.1 rate. Google's card also lists a Batch tier for 2.1 at $0.0168, $0.0252 and $0.0567 per image, exactly half of Standard at 1K and 2K and about half at 4K.

Do not read the Google card as a promise about future prices. It is a snapshot read on 2026-10-09, and Google's page labels the model gemini-nano-banana-2.1 with a link to try it in AI Studio.