Which is cheaper, Gemini 3.1 Pro Preview or Gemini 3.1 Pro Preview Custom Tools?

Gemini 3.1 Pro Preview, at $9 per million tokens against $18 for Gemini 3.1 Pro Preview Custom Tools, three parts input to one part output, read on 16 Sept 2026.

Where is each one cheapest?

Gemini 3.1 Pro Preview: $9 at Kilo Gateway. Gemini 3.1 Pro Preview Custom Tools: nobody goes below the maker's own price with a reason we can point at, so $18 is the number to beat.

Can I buy both from one provider?

Yes. 11 providers sell both: Kilo Gateway, AIHubMix, Eden AI, Google, Google Vertex AI, LLMTR, and more. The cheapest of them for the two together is Kilo Gateway.

Which holds more context?

Both hold 1M tokens in one call.

Gemini 3.1 Pro Preview vs Gemini 3.1 Pro Preview Custom Tools.

model vs model · prices as of 16 Sept 2026

Gemini 3.1 Pro Preview takes 1 of 5 rounds against Gemini 3.1 Pro Preview Custom Tools. It is also the cheaper of the two to run, at $9 per million tokens against $18.

Googlewins 1 rounds

Gemini 3.1 Pro Preview

$9/M tokens

cheapest we can explain, at Kilo Gateway · $0.96 per 1,000 pages

1M context · tool calling · reads images

Kilo Gateway ↗

Google

Gemini 3.1 Pro Preview Custom Tools

$18/M tokens

Google list price, nothing below it is accounted for · $1.92 per 1,000 pages

1M context · tool calling · reads images

List price in (lower wins)

$2/M

List price out (lower wins)

$12/M

Cheapest we can explain (lower wins)

$9/M at Kilo Gateway

none below list

Standard price (lower wins)

$18/M

Cost per 1,000 pages (lower wins)

$0.96

$1.92

Context

1M tokens

Open weights

Tool calling

yes

Structured output

yes

Reads images

yes

Reasoning

yes

Released

19 Feb 2026

Providers selling it

Price we measure against

the maker's own

Trains on your prompts (no is better)

not stated

no provider to check

Providers selling both · 11

Kilo Gateway$9 / $18
AIHubMix$18 / $18
Eden AI$18 / $18
Google$18 / $18
Google Vertex AI$18 / $18
LLMTR$18 / $18
Merge Gateway$18 / $18
NanoGPT$18 / $18

Gemini 3.1 Pro Preview then Gemini 3.1 Pro Preview Custom Tools, per million tokens · showing the 8 cheapest of 11

Go further

open in the compare tool →every price for Gemini 3.1 Pro Preview every price for Gemini 3.1 Pro Preview Custom Tools

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What moved in the last seven days

Gemini 3.1 Pro PreviewNous Portal$1.60 / $9.60 $2 / $1225% dearer · 16 Sept 2026
Gemini 3.1 Pro Preview Custom ToolsNous Portal$1.60 / $9.60 $2 / $1225% dearer · 16 Sept 2026

Frequently asked

Which is cheaper, Gemini 3.1 Pro Preview or Gemini 3.1 Pro Preview Custom Tools?: Gemini 3.1 Pro Preview, at $9 per million tokens against $18 for Gemini 3.1 Pro Preview Custom Tools, three parts input to one part output, read on 16 Sept 2026.
Where is each one cheapest?: Gemini 3.1 Pro Preview: $9 at Kilo Gateway. Gemini 3.1 Pro Preview Custom Tools: nobody goes below the maker's own price with a reason we can point at, so $18 is the number to beat.
Can I buy both from one provider?: Yes. 11 providers sell both: Kilo Gateway, AIHubMix, Eden AI, Google, Google Vertex AI, LLMTR, and more. The cheapest of them for the two together is Kilo Gateway.
Which holds more context?: Both hold 1M tokens in one call.

Prices exclude tax and are per million tokens, read 16 Sept 2026 from each provider's own catalog. The standard price blends three parts input to one part output; a page is 600 tokens in and 60 out. Bars are scaled to the larger value in each row.