Free SaaS Calculators

Quick, transparent calculators for SaaS and AI startup founders: LLM API cost, runway and burn rate, LTV:CAC, CAC payback, churn and net revenue retention. Each page shows the formula and its source. Nothing you type leaves your browser.

LLM API cost calculatorMonthly cost of Claude, GPT and Gemini API calls per request, per user and per month. Runway & burn calculatorMonths of cash left from your burn rate, with optional revenue and cost growth. LTV:CAC calculatorCustomer lifetime value, CAC and the LTV:CAC ratio from ARPA, margin and churn. CAC payback calculatorMonths to recover customer acquisition cost, with and without churn. Churn & NRR calculatorCustomer churn, gross and net MRR churn, GRR and net revenue retention.

Why these five

They answer the questions an AI SaaS plan keeps coming back to: how much each user costs to serve with a language model, how long the cash lasts, whether acquisition pays for itself, and how fast revenue leaks away. The formulas are the standard ones described by David Skok, “SaaS Metrics 2.0 – A Guide to Measuring and Improving what Matters” (For Entrepreneurs) and Andreessen Horowitz, “16 Startup Metrics”; the LLM prices come from each provider’s official pricing page, checked on 2026-10-07.

Need the full 5-year model?

These calculators each look at one number. The AI SaaS Financial Model connects them all in one Excel workbook for 60 months.

60 monthly columns: 3 pricing plans with their own churn, MRR and ARR, LLM token cost per customer with a monthly price decline
Hiring plan by role, CAC, G&A, working capital, two equity rounds, tax with losses carried forward
Integrated income statement, cash flow statement and balance sheet (balance check every month), annual summary and DCF
Dashboard: ARR, gross and EBITDA margins, lowest cash balance, first EBITDA-positive month, LTV/CAC, CAC payback

Get the AI SaaS Financial Model – $39

One Excel .xlsx file, no macros, tested in Microsoft Excel for Windows. Sold through Gumroad. Default figures are illustrative examples, not a forecast.