Gemini 3.1 Pro Preview Custom Tools API pricing.
Gemini 3.1 Pro Preview Custom Tools is Google’s model on the API market, released 25 Feb 2026. Prices are per million tokens in USD, as last read from the price list.
The index combines many benchmarks into one general-capability score; the range is how sure Epoch is of the number. Each area score is this site's average of the model's Epoch results in that area, where 0 is what guessing would score and 100 is perfect. Compare every model, and value for money →
Source: Epoch AI, Capabilities & benchmarking (licensed CC BY 4.0). Data refreshed 2 November 2026. These are Epoch's own tests; other benchmark sites can rank models differently.
- Provider
- Model id
google/gemini-3.1-pro-preview-customtools- Input
- $2.00
- Output
- $12
- Cached input
- $0.20
- Context window
- 1.0M tokens
- Maximum output
- 66K tokens
- Takes
- text, audio, image, video, file
- Returns
- text
- Tool use
- Yes
- Reasoning
- Yes
- Released
- 25 Feb 2026
- First tracked
- 17 Sept 2026
At $2.00 per million input tokens, Gemini 3.1 Pro Preview Custom Tools is dearer than 264 of the 340 models on the price list.
No price change has been recorded since tracking began on 17 Sept 2026. Prices are checked every six hours, and any change is listed here and on model changes.
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Prices and specifications come from OpenRouter’s catalogue, last read 2 Nov 2026. A provider’s own price may differ; how this is collected.