What is FounderCalc?
FounderCalc is a set of free, instant business calculators built for the same people who built it: indie founders, freelancers, and early-stage SaaS builders who need fast, accurate answers without signing up for a dashboard or wading through a spreadsheet.
Every calculator runs entirely in your browser. When you enter numbers into any tool on this site, those numbers never leave your device.
The tools
The current calculator suite covers the questions that come up constantly when you're running a small digital business:
- Payments — Stripe fee calculator so you know exactly what you receive.
- SaaS metrics — MRR, ARR, LTV:CAC ratio, startup runway, and churn impact.
- Freelance — minimum hourly rate based on income targets and tax, salary-to-hourly conversion.
- Business math — profit margins, break-even analysis, VAT/sales tax.
Why we built this
These calculations aren't hard, but doing them from scratch in a spreadsheet every time is friction that slows decisions. A single-purpose calculator that opens instantly, pre-filled with sensible defaults, gets you an answer in 10 seconds.
No tracking, no sign-up
All computation is client-side JavaScript. There is no account, no email required, and no analytics tracking what you type. The only data that leaves your browser is a standard server request for the HTML page itself.
If you have a suggestion for a calculator that would be useful, you can reach us via the contact page.