About SimpleFin.pl
Independent financial calculators with no hidden agenda.
SimpleFin.pl was created from the need for tools that show the true cost of a loan — without the marketing noise.
My name is Damian and I'm a programmer.
When I took out my first mortgage, I faced hundreds of pages of documents written in language that seemed intentionally incomprehensible. So I started calculating myself — first in Excel, then in Python.
I wanted to know exactly: how much does the loan actually cost me and how do different decisions (overpayments, interest rate changes) affect the final amount to repay.
Why was SimpleFin.pl created?
Most loan calculators on the Polish internet belong to banks or financial intermediaries. Their main goal is sales, not education. They show an attractive installment but rarely explain that over 30 years you'll pay back much more than you borrowed.
SimpleFin.pl offers independent tools built with transparency in mind.
Transparency
If overpaying your loan is worth it — you'll see it on the chart. If not — you'll see that too.
Open Mathematics
Under every tool you'll find the formula used for calculations. No "magic" in the background.
Your Interest First
Every calculator is designed to help you make informed financial decisions.
SimpleFin.pl is not a large company. It's a project by one programmer who believes that ordinary people deserve the same analytical tools as financial institutions.
Use it, calculate, and save.
Project Principles
Privacy
No data is collected. All calculations are performed locally in your browser.
Precision
Calculations use high-precision math libraries (Decimal.js). In finance, there's no room for approximations.
Independence
The project is privately funded, with no ties to banks or financial intermediaries.
For Developers
Technical information:
SimpleFin.pl is built on Astro and Preact. The priority was performance and minimal JavaScript, so the site works fast even on slower devices.
Damian