// project_case_study

FORFETTARIO
2026

A free web app for the roughly two million Italian freelancers on the regime forfettario. Enter what you invoiced and see your taxes, INPS contributions, net income, F24 forms and payment calendar in seconds.

Web AppFintechLive2026
Try it free
Forfettario 2026 tax calculator: €40,000 of revenue gives an estimated net of €30,041.25, with INPS contributions, flat tax and the share to set aside on each invoice
Tax calculator: from revenue to net income, with the share to set aside on every invoice.

The problem

The flat-tax regime is simple on paper, but the money side isn't: down payments, the second-year June peak, INPS rules that differ by fund, and F24 tax codes. Most freelancers find out how much they owe a few days before the deadline.

What we shipped

  • Tax calculator: flat tax (5% or 15%), INPS contributions, net income and the percentage to set aside on every invoice.
  • "Quanto fatturare": works backwards from the net you want to the revenue, daily and hourly rate you need.
  • F24 simulator for the June and November forms, with tax codes (1790, 1791, 1792), INPS causali and credits.
  • Multi-year payment simulator that shows the second-year June peak before it hits.
  • Plain-language guides on down payments, INPS contributions and the €85,000 threshold, plus a downloadable Excel tracker.
  • One calculation engine shared by every tool, checked against hand calculations and spreadsheets, with end-to-end tests on desktop and mobile.

Stack

A fast static web app with in-app navigation and a profile saved on the device (no account needed), a shared JavaScript calculation engine, and Playwright tests. A Next.js version with a JSON and iCalendar API for deadlines is in development.

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