At 40 requests/user/day (totaling 600,000 queries/mo), running AI coding assistant on Gemini 3.5 Flash (OpenRouter) costs $15,768.00 / month ($31.536 / user / mo).
Total expected API invoice for 500 Active Users generating 600,000 queries.
Direct inference cost per MAU to model your SaaS pricing tiers and gross margins.
Savings generated by exploiting 60% cache hits on prompt context.
| Model | Provider | Monthly Spend (500 Active Users) | Cost / User / Mo | Annual Spend | Context Limit |
|---|---|---|---|---|---|
| Gemini 3.5 Flash (OpenRouter) (Current) | $15,768.00 | $31.536 | $189,216.00 | 1,048,576 | |
| GPT-5.6 Terra | openai | $21,024.00 | $42.048 | $252,288.00 | 1,050,000 |
| GPT-5.4 Workhorse | openai | $26,280.00 | $52.56 | $315,360.00 | 256,000 |
| o3-mini | openai | $10,824.00 | $21.648 | $129,888.00 | 200,000 |
| o4-mini | openai | $9,636.00 | $19.272 | $115,632.00 | 256,000 |
| o1-mini | openai | $10,824.00 | $21.648 | $129,888.00 | 128,000 |
At 40 queries per user/day with Gemini 3.5 Flash (OpenRouter), the estimated cost is $31.536 per monthly active user (MAU). Total monthly bill for 500 Active Users is $15,768.00.
Assuming a 60% cache hit rate on repeated system and context tokens, prompt caching saves $5,832.00 per month ($69,984.00/year) on Gemini 3.5 Flash (OpenRouter).
With a direct COGS of $31.536 per user/month on Gemini 3.5 Flash (OpenRouter), charging at least $157.68 per user/month ensures an 80%+ software gross margin.