The problem
Splitting income by percentages — taxes, the military levy, savings, the 50/30/20 rule — sounds trivial until rounding every share separately leaves you a kopiyka short or over, and the total no longer balances. People were doing it by hand in calculators and spreadsheets, re-entering the same schemes every time, and had no quick offline tool that simply guaranteed the math added up.
My approach
I built a lightweight cross-platform app where every split is computed in whole kopiykas so the parts always sum back to the original amount with zero rounding error. On top of the calculator I added reusable presets — create, edit, and duplicate your own percentage templates — plus built-in FOP schemes (Single Tax Group 3, military levy). Everything works fully offline with data stored on-device, presets export/import as JSON for moving between phones, and the UI ships in three languages with light and dark themes that follow the system.
The result
A focused utility that turns a fiddly, error-prone calculation into a two-second action and is live on Google Play. Entrepreneurs reconcile taxes per payment, sellers see net profit after commissions instantly, and budgeters divide income by their own rules — all without internet and without rounding surprises.
Key highlights
- Kopiyka-precise math — shares always sum back to the total, no rounding drift
- Built-in FOP presets: Single Tax (Group 3) and military levy
- Custom presets you can create, edit, and duplicate
- Fully offline — data stays on the device
- JSON import/export to move presets between devices
- Trilingual UI (UA / EN / RU) with light & dark themes
- Published on Google Play as a native build via Capacitor