All your everyday math, in one box.
No ads · 30+ practical tools · Themes
Meet Sumbox & TimesoriaSumbox is coming soon · Not available in mainland China at launch
For iPhone and iPad · iOS 17 or later · English, 简体中文, 繁體中文A calculator plus 30+ practical tools, all free with no sign-up.
Basic and scientific modes. Addition, subtraction, multiplication, and division use exact decimal arithmetic, so 0.1 + 0.2 is exactly 0.3; percent, repeated equals, and automatic closing parentheses work the way you expect from a calculator.
Daily reference rates for 19 currencies, with the latest rates cached for offline use; 12 categories of units, including traditional Chinese units such as jin, liang, mu, and chi.
What do you call your father’s younger sister’s son? Relationship chains of up to 12 steps, mutual titles, and relative ages — each title comes with pinyin and an English explanation, worked out on your device.
Monthly take-home pay, which year-end bonus tax method costs less, and whether the annual reconciliation means a refund or a payment (China mainland rules); a reading such as “123 million” next to large results, RMB amounts written in the Chinese numerals used on checks and invoices in one tap, and installment fees turned into a true annual rate.
Mortgages, compound interest, discounts, splitting the bill, BMI, days between dates, age and Chinese zodiac, plus hashes, number bases, Base64, timestamps, and password generation.
Turn on Focus Mode to hide the tab bar and make the keys bigger; your history is always a tap away, and Reuse puts any saved calculation back on the calculator.
Real iPhone screens. Ready when you are.
Every theme has its own colors, key shapes, digit font and key sounds, plus a matching app icon. Mint and Clear Contrast are free forever; try on any other theme in full, then unlock them all with a single purchase. Family Sharing is included, and themes added later come at no extra charge.
Colors are approximate; see the app for the actual themes.
Sumbox has no accounts and no advertising, analytics, or tracking tools.
Get the apps
Sumbox makes room for everyday math. Timesoria makes room for moments that matter.
All your everyday math, in one box.
Standard and scientific calculation, 30+ practical tools, and themes that feel like you.
Coming soon to the App StoreNot available in mainland China at launch.
Save today. Write to your future self.
Keep a few words, photos, or a voice recording, then meet your past self again.
Download on the App Store Explore Timesoria
Sumbox 算盒