däpter — your smart notepad

The notes app where every line can calculate. Type 100 usd in eur or today + 21 days and the answer appears instantly. No calculator, no servers, no internet.

däpter is the notes app that does the math for you.

Just start typing. Any line that looks like a calculation lights up and shows its answer in the margin — instantly, as you type. The rest stays plain text. It's a notebook and a calculator in one, and it speaks plain English.

WRITE MATH LIKE A SENTENCE • 2 + 2, (120 × 1.2) / 4 — answers appear the moment you type them • 20% of 300, 200 - 10% — percentages, markups and discounts the way you'd say them • 100 usd in eur, $50 + 20% — live currency conversion with proper money formatting • 10 km + 5 m in miles, 6 m / 2 s → 3 m/s — real units that convert and combine correctly • today + 21 days, 3 days + 12 hours — plan, count down and schedule inside a note

MAKE A NOTE INTO A TINY SPREADSHEET • Name values and reuse them: rate = 45, then rate × hours on a later line • Running totals: sum a block for budgets, receipts and quick tallies • Built-in functions and constants: round, sqrt, pi, and more

PROSE AND NUMBERS, TOGETHER Write like you normally would. Only the calculation lines light up, syntax-highlighted live so a note reads clearly at a glance. One broken line never breaks the rest of your note.

PRIVATE BY DESIGN Everything is computed on your device, with no servers and no account. Your notes and numbers never leave your phone. All the calculating, unit conversion and currency math is free, forever.

BUILT FOR EVERY DEVICE A clean, native, Apple-Notes-style experience on iPhone and iPad, with light and dark themes. Available in English, Russian and Kazakh.

DÄPTER PLUS Upgrade to Plus for unlimited notebooks and to support independent, local-first software. Available as a monthly, yearly or one-time lifetime purchase.

Perfect for budgets, invoices, travel planning, freelance quotes, recipes, quick estimates — anywhere you'd otherwise reach for a calculator and then forget what the numbers were for.

Terms of Use (EULA): https://www.apple.com/legal/internet-services/itunes/dev/stdeula/