US Quarter Size & Dimensions
The US Quarter is one of the most reliable reference objects for calibrating a screen ruler. With a standard diameter of 24.26mm (2.4cm / 0.96 inches), it provides a consistent size that you can use to calibrate your screen for accurate measurements.
US Quarter Exact Dimensions
Millimeters
24.26 mm diameter
Centimeters
2.4 cm diameter
Inches
0.96" diameter
US Quarter coin
How to Calibrate with a US Quarter
- Open the screen ruler on your device and select US Quarter from the calibration panel.
- Place your us quarter flat on the screen, aligning it with the on-screen outline.
- Adjust the calibration slider until the outline matches your us quarter exactly.
- The calibration is saved automatically. You can now measure any object with the ruler and get accurate readings in centimeters, millimeters, and inches.
Why Use a US Quarter for Calibration?
Calibration is essential because every screen has a different pixel density (PPI). A pixel on a 6-inch phone screen is physically much smaller than a pixel on a 27-inch desktop monitor. By placing a known-size object on the screen, the ruler can calculate the exact physical size of each pixel and convert measurements accurately.
Coins like the US Quarter are particularly useful because they are standardized, widely available, and easy to position on a screen. Their circular shape makes alignment straightforward.