At 4 requests/user/day (totaling 60,000 queries/mo), running Document summarization on Gemini 3.1 Pro costs $3,162.00 / month ($6.324 / user / mo).
Total expected API invoice for 500 Active Users generating 60,000 queries.
Direct inference cost per MAU to model your SaaS pricing tiers and gross margins.
Savings generated by exploiting 10% cache hits on prompt context.
| Model | Provider | Monthly Spend (500 Active Users) | Cost / User / Mo | Annual Spend | Context Limit |
|---|---|---|---|---|---|
| Gemini 3.1 Pro (Current) | $3,162.00 | $6.324 | $37,944.00 | 2,000,000 | |
| GPT-5.6 Sol | openai | $7,905.00 | $15.81 | $94,860.00 | 1,050,000 |
| GPT-5.6 Cyber | openai | $19,762.50 | $39.525 | $237,150.00 | 1,050,000 |
| GPT-5.5 Standard | openai | $7,905.00 | $15.81 | $94,860.00 | 512,000 |
| GPT-5.5 Pro | openai | $47,430.00 | $94.86 | $569,160.00 | 512,000 |
| o3-pro (Frontier Reasoning) | openai | $30,180.00 | $60.36 | $362,160.00 | 1,000,000 |
At 4 queries per user/day with Gemini 3.1 Pro, the estimated cost is $6.324 per monthly active user (MAU). Total monthly bill for 500 Active Users is $3,162.00.
Assuming a 10% cache hit rate on repeated system and context tokens, prompt caching saves $270.00 per month ($3,240.00/year) on Gemini 3.1 Pro.
With a direct COGS of $6.324 per user/month on Gemini 3.1 Pro, charging at least $31.62 per user/month ensures an 80%+ software gross margin.