AI SaaS unit economics

Monthly SaaS Tier vs. API Cost Calculator

Compare per-user SaaS subscription revenue against buffered monthly API usage and estimate gross margin, cost per user, and break-even usage.

Per-user subscription modelGross-margin target comparisonBreak-even usage estimate

SaaS vs. API estimate

Per-user subscription model

Healthy margin

The estimated gross margin meets or exceeds your target.

Estimated monthly API cost

$3,450.00

Gross margin estimate

76.21%

API cost per user

$6.90

Revenue per user needed

$27.60

To reach the selected gross margin target

Break-even requests per user per day

84.06

At the current subscription price and buffered API cost

Calculation basis

Buffered requests per month: 345,000
Estimated monthly revenue: $14,500.00
Estimated gross profit: $11,050.00

Formula

How SaaS margin is estimated

Buffered API requests are priced across active users, then compared with per-user subscription revenue.

Monthly API cost = buffered requests per user × users × request cost

Gross margin = (subscription revenue − API cost) ÷ subscription revenue

Required revenue per user = API cost per user ÷ (1 − target margin)

saas-vs-api.ts

export function saasMargin(input: {
  pricePerUser: number;
  costPerRequest: number;
  requestsPerUserPerDay: number;
  users: number;
  daysPerMonth: number;
  bufferPercent: number;
}) {
  const bufferedRequests =
    input.requestsPerUserPerDay *
    input.users *
    input.daysPerMonth *
    (1 + input.bufferPercent / 100);
  const apiCost = bufferedRequests * input.costPerRequest;
  const revenue = input.pricePerUser * input.users;

  return {
    apiCost,
    grossMarginPercent: ((revenue - apiCost) / revenue) * 100,
  };
}

Example AI SaaS margin estimate

A $29 per-user plan with twenty daily requests and one-cent API cost spends about $6 per user over a thirty-day month before the safety buffer.

The recommendation is a planning signal, not accounting advice. Add every other cost category before setting final pricing.

What this estimate includes

Buffered request volume and monthly API cost
Subscription revenue across active users
API cost and required revenue per user
Gross-margin target and break-even request volume

Frequently asked questions

Is the subscription price entered per user?

Yes. The Phase 2 calculator treats the SaaS monthly subscription price as revenue per active user and multiplies it by active users.

What is a healthy gross margin for AI SaaS?

Targets vary by company and product. The calculator compares your estimated margin with the percentage you enter rather than prescribing one universal target.

What does break-even requests per user mean?

It is the approximate daily request volume where buffered API cost consumes the full per-user subscription price before any other expenses.

What costs are excluded?

Payroll, hosting outside the modeled API, databases, support, payment fees, sales, taxes, churn, and usage by non-paying users are excluded.

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Related glossary terms

Input tokens

Input tokens are the tokenized units sent to a model, including instructions, user content, conversation history, retrieved context, and tool definitions.

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Requests per day

Requests per day is the number of billable API calls made during a day. TokenMath commonly derives it from requests per active user multiplied by active users.

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Cost per request

Cost per request is the sum of all billable usage generated by one API call, commonly input token cost plus output token cost for a text model.

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