A Sumlock-style running total calculator with fraction input and memory recall. The converter runs on two scroll wheels — tactile and intuitive on mobile, with hotkeys and keyboard input for desktop.
Converter
- Length — inches ↔ centimeters, with fraction, half, and feet sub-info
- Pixels — inches or cm ↔ pixels at adjustable PPI (72–600)
- Vol/Weight — oz/lb ↔ ml/kg, with tablespoon, cup, pint, quart, gallon, and metric equivalents
- Temp — °F ↔ °C, with air, reference, and cook presets
Calculator
- Standard arithmetic with a fraction slider (1/32 increments)
- Memory bank — stores up to 8 values, tap to recall
- SET IMPERIAL / SET METRIC — sends calculator result directly to the converter
Design
- Light and Dark color modes
- Fully self-contained single HTML file — no server, no dependencies at runtime
- Works offline once loaded
- Responsive — full width on mobile, 55% centered column on desktop
| Key | Action |
|---|---|
C |
Toggle between Calculator and Converter |
W |
Cycle color themes (Light → Dark) |
| Key | Action |
|---|---|
→ |
Next converter mode |
← |
Previous converter mode |
0–9 |
Type digits into left wheel |
Backspace |
Remove last digit from left wheel |
Z |
Zero both wheels |
| Key | Action |
|---|---|
0–9, . |
Number input |
- |
Minus |
= or + |
Plus |
X or * |
Multiply |
/ |
Divide |
Enter |
Equals |
Backspace or Delete |
Delete last digit |
Z |
Clear everything |
% |
Percent |
M |
Set Metric → switch to converter |
I |
Set Imperial → switch to converter |
Cmd/Ctrl + C |
Copy current result |
One of the best ways to use Calc*on is straight from your iPhone home screen. It eliminates the browser UI entirely — no address bar, no tabs — and just gives you the app full screen, exactly as it was designed to be used.
- Open Calc*on in Safari on your iPhone
- Tap the Share button (the box with the arrow pointing up) at the bottom of the screen
- Scroll down and tap "Add to Home Screen"
- Give it a name and tap Add
It'll sit on your home screen like any other app. Great for quick lookups on the job.
- Vanilla JS — no framework
- Geist via Google Fonts
- SVG scroll wheels with physics-based ridge animation
- Vibration API for haptic feedback on supported devices (Android Chrome)
This project is licensed under the GNU General Public License v3.0.
You are free to use, modify, and distribute this software under the same license terms.
Christopher Cunningham
github.com/christophcunningham