calibration

Choose The Right Calibration Method.

Browser pixels are not guaranteed to match physical inches. Calibration gives the ruler a reliable scale for your screen.

Method 1

Auto-Detect Device

Use this when you need a fast starting point. It estimates the screen scale from browser data and device hints, then lets you refine later.

  1. Open the Scale product page.
  2. Select Detect Device.
  3. Check the ruler against a known physical object.

Method 2

Screen Diagonal

Use this when you know the exact diagonal size of your laptop, monitor, tablet, or phone display.

  1. Find your display diagonal in inches.
  2. Enter the value in the ruler calibration panel.
  3. Apply the result and measure at 100% browser zoom.

Method 3

Credit Card Calibration

Use this for the strongest practical calibration. A standard card is 85.60 mm wide, making it easy to match the guide on screen.

  1. Place a standard card on the screen.
  2. Adjust the guide until the card edges match.
  3. Save the calibration for future visits.