At 40 requests/user/day (totaling 3,000,000 queries/mo), running AI coding assistant on o4-mini costs $48,180.00 / month ($19.272 / user / mo).
AI coding assistant for a 2,500 active users (series a product) audience means 100,000 requests per day on average, each carrying 12,000 input and 2,000 output tokens at a 60% cacheable share — so the effective per-request cost on o4-mini is $0.0161, of which $17,820.00/mo comes back from prompt caching. Per active user that's $19.272/mo — the number to hold against your pricing tier and gross margin. Charging at least $96.36/user/mo keeps gross margin at or above 80%.
Quick answer
For 2,500 Active Users, AI coding assistant on o4-mini is modeled at 3,000,000 requests per month, costing $48,180.00 per month or $19.272 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 2,500 Active Users generating 3,000,000 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 (2,500 Active Users) | Cost / User / Mo | Annual Spend | Context Limit |
|---|---|---|---|---|---|
| o4-mini (Current) | openai | $48,180.00 | $19.272 | $578,160.00 | 256,000 |
| GPT-5.6 Terra | openai | $105,120.00 | $42.048 | $1,261,440.00 | 1,050,000 |
| GPT-5.4 Workhorse | openai | $131,400.00 | $52.56 | $1,576,800.00 | 256,000 |
| o3-mini | openai | $54,120.00 | $21.648 | $649,440.00 | 200,000 |
| o1-mini | openai | $54,120.00 | $21.648 | $649,440.00 | 128,000 |
| Claude Sonnet 5 | anthropic | $93,120.00 | $37.248 | $1,117,440.00 | 1,000,000 |
At 40 queries per user/day with o4-mini, the estimated cost is $19.272 per monthly active user (MAU). Total monthly bill for 2,500 Active Users is $48,180.00.
Assuming a 60% cache hit rate on repeated system and context tokens, prompt caching saves $17,820.00 per month ($213,840.00/year) on o4-mini.
With a direct COGS of $19.272 per user/month on o4-mini, charging at least $96.36 per user/month ensures an 80%+ software gross margin.