AI API Spend Forecast Calculator

API Spend Forecaster

Building an AI Wrapper or SaaS? Estimate your monthly OpenAI bill before you launch.

How many times they hit 'Send'.
User prompt size.
AI response size.

How This Forecast Tool Works

The API Spend Forecaster is designed for SaaS founders and developers building "AI Wrappers" or integrated enterprise tools. It takes your projected user metrics and converts them into a monthly dollar amount based on real-time token pricing from OpenAI, Anthropic, and Google.

How to Use the Forecaster

  • Daily Active Users (DAU): The number of unique people hitting your AI features every 24 hours.
  • Interactions: How many prompts a single user sends per day.
  • Token Averages: The typical size of a user prompt (Input) and the AI response (Output).
Example: AI Writing Assistant SaaS

You have 1,000 monthly subscribers, with 200 using the app daily (200 DAU).

- Usage: 10 prompts per user / day
- Model: Claude 3.5 Sonnet
- Tokens: 1k Input / 1k Output per prompt
- Monthly Bill: ~$1,080.00

If you charge $20/user, your revenue is $20,000. Your AI cost is ~5.4% of revenue—a healthy margin for an AI-first business.

Startup Tip: Always include a 15% buffer in your pricing model. Token usage is rarely consistent; a few power users can significantly spike your average daily spend.

AI Business Intelligence FAQ

What is a 'Reasonable' AI Margin?

For most SaaS companies, AI API costs should ideally sit between 5% and 15% of your gross revenue. If your costs exceed 30%, you likely need to optimize your prompts or move tasks to a smaller model.

How do I monitor live spend?

Most serious developers use tools like Helicone or LangSmith. These act as proxies that log every token sent and received, giving you a real-time analytics dashboard of your spend per user.

Can I get a volume discount?

Yes. If you are spending over $10,000/month, you can often negotiate 'Reserved Capacity' with Microsoft Azure or Amazon Bedrock to get lower rates than the standard public API pricing.