Sumi: Notepad Calculator

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 total = 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 the lines above it that don't have a name. Change one number and the rest update. Lines of plain words are just notes, so you can label things the way you like. Currencies: about 160 of them, plus 20 cryptocurrencies, including USD, EUR, GBP, JPY, IDR, SGD, INR and AUD. Live exchange rates are free, and built-in rates take over when you're offline. Prices per unit work too: "1.2 jt IDR per m2 × 200 m2" or "4 USD per kg". Units: weight, length, volume, area, speed, temperature, data, energy and time zones ("2:30 pm HKT in Berlin"). Lengths multiply into areas: "12 m × 8 m" is 96 m². There's a Guide in the app explaining every feature, and a reference listing every unit and shortcut; 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. Type / for quick commands: jump to another sheet, start a new one, rename it, change the theme or share. 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 = 120 EUR" and then "dinner / 4". Tap the answer to add names and tick off who has paid. For a whole receipt, write each person and what they had, plus shared dishes, tax and service, and Sumi works out who owes what. Start a section with a # line and fold it down to its subtotal. 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 iPhone. With Sumi Pro you can turn on iCloud sync to keep them on your iPhone and Mac; they go to your own iCloud account and nowhere else. Sumi is free with up to 3 sheets, live exchange rates, Cream and Espresso themes (or Auto, which follows your iPhone's light and dark mode) and the small Home Screen widget. Sumi Pro is a one-time purchase, with a 7-day free trial and Family Sharing, and it's the same purchase on iPhone and Mac. It adds unlimited sheets, iCloud sync, 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