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About Notes Calculator

Notes Calculator is built by Alexandru Mariuti, a solo developer. One person designs, writes, tests and supports the app on every platform.

Who builds it

Alexandru Mariuti is a Flutter developer based in Turin, Italy. He has built mobile apps since 2018: first in Java and Kotlin for Android and Swift for iOS, and since January 2020 mostly in Flutter and Dart, which is also what Notes Calculator is written in.

He maintains open-source packages for Flutter and Dart, published on GitHub as nank1ro:

  • shadcn_ui, the shadcn/ui components ported to Flutter (about 2,800 stars)
  • solidart, signals for Dart and Flutter inspired by SolidJS (about 230 stars)
  • solid, a small framework on top of Flutter with fine-grained reactivity (about 165 stars)
  • disco, scoped providers for dependency injection in Flutter

Star counts as shown on GitHub on October 10, 2026.

Besides Notes Calculator, he makes Manico (a keyboard app switcher for macOS), Codigo (learn to code on iOS and Android) and FitPrint (fit PDFs and photos onto print sheets on macOS). He writes about Flutter, Dart and developer tools on his blog at mariuti.com.

What it is and why it exists

Notes Calculator is a notepad calculator. You write calculations as plain text, one per line, and the answer appears as you type. It understands variables, units and more than 200 currencies.

Everyday math often falls between a basic calculator, which forgets your working, and a spreadsheet, which asks for cells and formulas. Notes Calculator keeps the working visible as text you can read, change and come back to. It has been written about on this blog since October 2023.

It runs on:

How the calculations are checked

The calculation engine has an automated test suite covering parsing, arithmetic, number bases, units, dates and time zones. Parity tests check that syntax shared with other notepad calculators gives the expected results.

The results on this site's unit converter and date pages are produced by running each example line through the same engine, not typed by hand. The full syntax is documented at docs.notescalculator.com. If you find a wrong answer, please report it.

How pricing works

The free plan includes the full calculator on one tab, with no time limit and no card required. Lifetime is a one-time payment, not a subscription, and adds unlimited tabs, sync across signed-in devices and priority support. Lifetime purchases are non-refundable, so try the free plan first. Payments are handled by Paddle. See pricing for the current price in your currency.

Contact

Email support@mariuti.com for support, feedback or questions, or use the contact page. You can also find Alexandru on GitHub, X and LinkedIn.