At 10 requests/user/day (totaling 30,000 queries/mo), running RAG / search-augmented answers on Qwen3.8 27B (OpenRouter) costs $145.80 / month ($1.458 / user / mo).
RAG / search-augmented answers for a 100 active users (public launch) audience means 1,000 requests per day on average, each carrying 8,000 input and 500 output tokens at a 50% cacheable share — so the effective per-request cost on Qwen3.8 27B (OpenRouter) is $0.00486, of which $0.00/mo comes back from prompt caching. Per active user that's $1.458/mo — the number to hold against your pricing tier and gross margin. Charging at least $7.29/user/mo keeps gross margin at or above 80%.
Quick answer
For 100 Active Users, RAG / search-augmented answers on Qwen3.8 27B (OpenRouter) is modeled at 30,000 requests per month, costing $145.80 per month or $1.458 per active user.
Method & trust
This projection combines the selected active-user tier, requests per user per day, input/output tokens per request, and the modeled cache share. It is an operating estimate, not a provider invoice; production traffic and retries should be measured against it.
Total expected API invoice for 100 Active Users generating 30,000 queries.
Direct inference cost per MAU to model your SaaS pricing tiers and gross margins.
Savings generated by exploiting 50% cache hits on prompt context.
| Model | Provider | Monthly Spend (100 Active Users) | Cost / User / Mo | Annual Spend | Context Limit |
|---|---|---|---|---|---|
| Qwen3.8 27B (OpenRouter) (Current) | qwen | $145.80 | $1.458 | $1,749.60 | 1,000,000 |
| GPT-5.6 Terra | openai | $444.00 | $4.44 | $5,328.00 | 1,050,000 |
| GPT-5.4 Workhorse | openai | $555.00 | $5.55 | $6,660.00 | 256,000 |
| o3-mini | openai | $264.00 | $2.64 | $3,168.00 | 200,000 |
| o4-mini | openai | $231.00 | $2.31 | $2,772.00 | 256,000 |
| o1-mini | openai | $264.00 | $2.64 | $3,168.00 | 128,000 |
At 10 queries per user/day with Qwen3.8 27B (OpenRouter), the estimated cost is $1.458 per monthly active user (MAU). Total monthly bill for 100 Active Users is $145.80.
Assuming a 50% cache hit rate on repeated system and context tokens, prompt caching saves $0.00 per month ($0.00/year) on Qwen3.8 27B (OpenRouter).
With a direct COGS of $1.458 per user/month on Qwen3.8 27B (OpenRouter), charging at least $7.29 per user/month ensures an 80%+ software gross margin.