Gemini 3.1 Pro API pricing — what it really costs
Gemini 3.1 Pro (Google) costs $2 per 1M input tokens and $12 per 1M output tokens — with prompt caching, cached input drops to $0.200. Preview; prompts up to 200K tokens; longer prompts cost $4/$18. Prices verified 2026-10-17; we track the price you are actually billed today, including promotional rates.
Price per 1M tokens
| Input | Output | Cached input |
|---|---|---|
| $2 | $12 | $0.200 |
Real monthly costs on Gemini 3.1 Pro
Three realistic workloads, computed from the prices above (cached share billed at the cache-read rate where the provider offers one):
Customer-support chatbot
$7.84/mo
2M input + 0.5M output tokens/month, 60% of input served from prompt cache
RAG / document Q&A
$26.80/mo
20M input + 1M output tokens/month, 70% cached (shared context)
Agentic coding assistant
$88.00/mo
50M input + 5M output tokens/month, 80% cached (long sessions)
Want exact numbers for your usage? Open the calculator — same verified prices, your token volumes.
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FAQ
How much does the Gemini 3.1 Pro API cost?
Gemini 3.1 Pro costs $2 per 1M input tokens and $12 per 1M output tokens. Cached input tokens cost $0.200 per 1M. Note: Preview; prompts up to 200K tokens; longer prompts cost $4/$18. Pricing verified 2026-10-17.
What does a typical workload cost on Gemini 3.1 Pro?
Customer-support chatbot: about $7.84/month (2M input + 0.5M output tokens/month, 60% of input served from prompt cache). RAG / document Q&A: about $26.80/month (20M input + 1M output tokens/month, 70% cached (shared context)). Agentic coding assistant: about $88.00/month (50M input + 5M output tokens/month, 80% cached (long sessions))
Is Gemini 3.1 Pro expensive compared to other models?
Gemini 3.1 Pro ranks #15 of 23 models by blended price in our comparison. The cheapest tracked models are Claude Haiku 5.5 and GPT-6 Luna at $0.100/$0.500 per 1M tokens.