Google · AI model API pricing

How much does Gemini 3.1 Pro cost?

Google's frontier tier (in preview) — the cheapest input price of any flagship-class model.

Rate card

What that means per month

Standard on-demand rates from Google's official pricing page, last checked 2026-07-28. Rates shown are for prompts ≤200k tokens; above 200k, input doubles to $4 and output rises to $18 per 1M. Batch runs at 50%. Monthly figures exclude caching and batch discounts. Confirm live pricing before committing.

Where Gemini 3.1 Pro sits on price

At the reference month of 10M input and 3M output tokens, Gemini 3.1 Pro costs $56, which makes it the 25th cheapest of the 30 models tracked here. That is 33× the price of Qwen-Flash, the cheapest model at this mix ($1.70). Among the 10 frontier-class models it ranks 5th, behind GLM-5.2 at $27.2.

Cache economics

Cached input on Gemini 3.1 Pro bills at $0.20 per 1M — 10% of its own input rate, against a 10% median across the models here that publish a cached-read price. 2 models discount cached reads more steeply than this. On the reference month, serving 80% of that input from cache takes the input side of the bill from $20 to $5.60, leaving output untouched at $36 — which is why a high reuse rate changes the ranking above rather than just shaving the total.

Cache reads only. Writes are billed separately by some providers and are excluded here — see the rate note above for Google's terms. Try it at your own hit rate on the AI cost calculator.

Cheaper alternatives

At a reference workload of 10M input / 3M output tokens a month, these cost less than Gemini 3.1 Pro ($56/mo):

• GPT-5.6 Terra $56/mo
• Claude Sonnet 5 $50/mo
• Gemini 3.5 Flash $42/mo

Gemini 3.1 Pro head-to-head