sukhomlinov
Wear OS smartwatch
A calculator that lives on your wrist
WatchCalc runs entirely on your watch - no phone, no internet, no account. Three swipeable screens take you from quick arithmetic to scientific functions and statistics, on a keypad designed for a round watch face and a fingertip.
Why WatchCalc
Standalone
Works without a companion phone app or a network connection. The app has no Internet permission at all, so nothing you calculate can leave your wrist.
Actually accurate
All arithmetic runs at 32-digit decimal precision, so 0.1 + 0.2 is exactly
0.3 and large numbers do not quietly lose digits.
Private by construction
No permissions, no analytics, no ads, no data collection of any kind.
Watch-first
Large tap targets, haptic feedback, and a display that fits the round screen with mode indicators along the edge. A compact download that launches instantly.
Basic screen
Left-to-right evaluation with explicit parentheses, the way a handheld calculator works.
Arithmetic
- Add, subtract, multiply, divide, with parentheses for grouping
- Percent, modulo, power (x^y), sign change and backspace
- Exponent entry, for example
5E-3
The display does the work
- Tap to cycle plain and scientific notation, short and full precision
- Thousands separators and up to 16 displayed digits, with a long-form mode showing full precision
Fewer mistakes
- Press
=again to repeat the last operation - Mistyped an operator? Just press the right one
- Division by zero and domain errors are reported clearly, and clear on the next key press
Scientific screen
Trigonometry
sin, cos, tan and their inverses in degrees, radians or gradians; sinh, cosh, tanh and their inverses. Inverse and hyperbolic toggles keep the keypad uncluttered.
Logarithms and powers
- ln, log10, e^x, 10^x
- x², x³, square root, cube root, reciprocal
Integers and rounding
- Factorial, GCD, LCM
- Floor, ceiling, round, fractional part, round to 2 decimals, absolute value
Constants and random
π and e, plus a random fraction from 0 to 1 - or a random integer from 1 to N when N is on the display.
Statistics screen
Enter data points one at a time, in single-variable or paired (x, y) mode.
Summary
Count, sum, sum of squares, mean, median, min, max and range.
Spread
Sample and population standard deviation, and variance.
Linear regression
Slope, intercept, correlation coefficient r and r². Predict y from x, or x from y, using the fitted line.
Fix a wrong entry
Delete the last point or clear the whole dataset at any time.
Requirements
Built for Wear OS 5 and newer (Android 14+), including Pixel Watch and Galaxy Watch. Swipe between screens, tap the display to change number format, and get answers without reaching for your phone.