Sumi: Notepad Calculator

Math notes, currency offline

Only for iPhone

Free · In‑App Purchases · Designed for iPhone. Not verified for macOS.

iPhone

New: split a bill and tick off who paid, fold long sheets to their subtotals, and tap any answer to see and restore what it was before. Sumi is a notepad where every line is a calculation. Write "rent = 2450 EUR" and it keeps the number. Write "rent / 4" on the next line and you get each person's share. I use it for trip budgets, splitting bills with housemates, counting hours for invoices and checking how many days are left until a deadline. It handles currencies, units, time and dates, so you can write things like: hotel = 128 EUR per night hotel × 4 prev + 15% total in usd round up 7.2 h 8 h × 5 days days until 25 dec Rp 150rb × 3 "prev" is the line above and "sum" adds up everything above it. Change one number and the rest update. Lines of plain words are just notes, so you can label things the way you like. Currencies: 18 of them, including USD, EUR, GBP, JPY, IDR, SGD, INR and AUD. Rates are built in, so conversion works offline. Units: weight, length, volume, area, speed, temperature, data and energy. There's a reference page listing every unit and shortcut, and you can tap an example to add it to your sheet. Big numbers: 2.5k, 1.2M and 3bn work, and so do rb, jt and miliar if you're used to writing Indonesian amounts. You can also pick how numbers look: 1,234.56, 1 234,56 or 1.234,56. While you type, the other lines fade back so you can see what you're working on. Hold a result to copy it. Search looks through every sheet, and you can copy a whole sheet as tidy aligned text to paste into a chat. Split a bill by writing "dinner / 4", then tap the answer and choose Split to add names and tick off who has paid. Start a section with a # line and fold it down to its subtotal. Tap any answer to see what it was before a number changed, and bring the old value back. Costs that grow over time work too: "server = 0.68 USD/h since 1 oct" keeps counting, and "figma = 15 USD/month on 15th" tracks a subscription. A Home Screen widget shows a sheet's total. There's no account and no ads, and nothing is tracked. Your sheets are stored on your phone and don't go anywhere else. Sumi is free with up to 3 sheets, two themes (Cream and Espresso) and the small Home Screen widget. Sumi Pro is a one-time purchase, with a 7-day free trial and Family Sharing. It adds unlimited sheets, live exchange rates, four Catppuccin themes (Latte, Frappé, Macchiato and Mocha), pinning a line's result to the bottom bar, sharing sheets and splits as images, medium, large and Lock Screen widgets, and alternate app icons. There's no subscription. Start free, no sign-up. If you need more sheets, try Pro free for 7 days. Questions or ideas: hello@trysumi.app

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Split the bill. Write "dinner / 4", tap the answer and choose Split: add names, tick off who has paid, and share the split as text or an image. Also in this update: - Fold a section: tap the number next to a # line and the section shrinks to its subtotal. Tap the pill to open it again. - Line history: tap any answer to see what it was before a number changed, and restore it in one tap. - Running costs: "server = 0.68 USD/h since 1 oct" keeps counting, and "figma = 15 USD/month on 15th" tracks a subscription. - Widgets: put a sheet's total on your Home Screen. - Smoother panels: drag a panel down to close it. - Typing stays smooth on long sheets. Something not adding up? Write to hello@trysumi.app.

The developer, Sigit Kuncoro, indicated that the app’s privacy practices may include handling of data as described below. For more information, see the developer’s privacy policy .

  • Data Not Collected

    The developer does not collect any data from this app.

    Privacy practices may vary, for example, based on the features you use or your age. Learn More

    The developer has not yet indicated which accessibility features this app supports. Learn More

    Seller
    Sigit Kuncoro
    Size
    7.4 MB
    Category
    Utilities
    Compatibility
    Requires iOS 17.0 or later.
    • iPhone
      Requires iOS 17.0 or later.
    • Mac
      Requires macOS 14.0 or later and a Mac with Apple M1 chip or later.
    • Apple Vision
      Requires visionOS 1.0 or later.
    Languages
    English
    Age Rating
    4+
    In-App Purchases
    Yes
    Copyright
    © 2026 Sigit Kuncoro