Gemini 3.1 Pro Preview Custom Tools API pricing
3 providers serve Gemini 3.1 Pro Preview Custom Tools. Gemini 3.1 Pro Preview Custom Tools is a proprietary API model, up to 1049K context. Prices below are per 1M tokens, cheapest input first.
Refreshed 2026-08-23 · list prices from provider APIs| Provider | Input $/1M | Output $/1M | Cache read $/1M | Context | |
|---|---|---|---|---|---|
| Google Vertex AI | $2.00 | $12.00output floor | $0.200 | 1049K | Use |
| Google Gemini API | $2.00 | $12.00 | $0.200 | 1049K | Use |
| OpenRouter marketplace quote | $2.00 | $12.00 | $0.200 | 1049K | Use |
The cheapest way to run Gemini 3.1 Pro Preview Custom Tools
On an illustrative 70M-input / 30M-output monthly workload, today's lowest listed cost is roughly $500/month — the same at Google Vertex AI, Google Gemini API and OpenRouter. Input-heavy, output-heavy and cache-heavy workloads can produce different winners. Use the live mix calculator below rather than combining floors from two different providers. It is API-only, so the table above is your full set of options. Run your own numbers in the breakeven calculator, or read the breakeven math.
Your actual monthly cost
Cache read uses the listed cache rate where available; otherwise it falls back to normal input price. Batch, write-cache, volume and negotiated discounts are excluded.
Related models
| Model | Cheapest in $/1M | Cheapest out $/1M | Providers |
|---|---|---|---|
| Gemini 2.5 Flash | $0.150 | $0.600 | 8 |
| Gemini 2.5 Pro | $1.25 | $10.00 | 7 |
| Gemini-3-Pro | $2.00 | $12.00 | 6 |
| Gemini 3 Flash Preview | $0.500 | $3.00 | 5 |
| Gemini 3.1 Flash Lite | $0.250 | $1.50 | 4 |
| Gemini 3.1 Pro Preview | $2.00 | $12.00 | 4 |
FAQ
What is the cheapest API for Gemini 3.1 Pro Preview Custom Tools?
As of 2026-08-23, the lowest input price for Gemini 3.1 Pro Preview Custom Tools, $2.00 per 1M tokens, is the same list price at Google Vertex AI, Google Gemini API and OpenRouter. The lowest output price, $12.00 per 1M tokens, is likewise shared by the same providers. The cheapest provider for a real workload depends on its input/output mix.
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