At 40 requests/user/day (totaling 600,000 queries/mo), running AI coding assistant on GPT-5.6 Luna costs $2,102.40 / month ($4.205 / 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 |
|---|---|---|---|---|---|
| GPT-5.6 Luna (Current) | openai | $2,102.40 | $4.205 | $25,228.80 | 1,050,000 |
| GPT-5.4 mini | openai | $7,884.00 | $15.768 | $94,608.00 | 256,000 |
| GPT-5.4 nano | openai | $2,162.40 | $4.325 | $25,948.80 | 128,000 |
| GPT-4o mini | openai | $1,476.00 | $2.952 | $17,712.00 | 128,000 |
| Claude Haiku 4.5 | anthropic | $9,312.00 | $18.624 | $111,744.00 | 1,000,000 |
| Claude 3.5 Haiku | anthropic | $7,449.60 | $14.899 | $89,395.20 | 200,000 |
At 40 queries per user/day with GPT-5.6 Luna, the estimated cost is $4.205 per monthly active user (MAU). Total monthly bill for 500 Active Users is $2,102.40.
Assuming a 60% cache hit rate on repeated system and context tokens, prompt caching saves $777.60 per month ($9,331.20/year) on GPT-5.6 Luna.
With a direct COGS of $4.205 per user/month on GPT-5.6 Luna, charging at least $21.024 per user/month ensures an 80%+ software gross margin.