Turn your phone or tablet screen into an accurate, high-precision measurement tool. Clean, customizable, and completely offline.
Traditional plastic rulers scratch or misalign. Real Free Ruler operates natively on your phone screen, offering pristine pixel-perfect accuracy.
Calibrate using standard reference items (like a coin or credit card) to adjust for your screen's precise manufacturer PPI.
All calibrations and measurements are processed locally. Zero network traffic, zero personal tracking, completely offline.
Toggle top, bottom, left, or right rulers. Switch between Centimeters, Inches, and raw Pixels with a single tap.
Use the interactive slider below to see how pixel-to-physical length conversion works. Drag the indicator to scale the ruler.