Click and drag on the ruler to measure • Ensure browser zoom is 100%
Online Ruler displays an actual-size ruler on your screen for measuring objects in inches, centimeters, or millimeters. Click and drag to measure distances precisely. Calibrate using a credit card for accurate measurements on any screen size or device.
Click and hold on the ruler at your starting point, then drag to the endpoint to see the measurement. The distance appears in real-time as you drag. For best accuracy, calibrate the ruler first using a standard credit card (85.6mm wide). Ensure your browser zoom is set to 100% for correct measurements.
Screen pixel density varies across devices, so calibration ensures accuracy. Click the Calibrate button, measure a credit card (exactly 85.6mm or 3.370 inches), enter what the ruler shows, and click Apply. The ruler automatically adjusts to display true measurements on your specific screen. Calibration saves to your browser for future use.
Perfect for quick measurements when no physical ruler is available - measuring small objects, checking photo dimensions, verifying sizes before online purchases, measuring jewelry, coins, keys, craft materials, or screen elements. Great for designers checking pixel-to-real-world dimensions. Works on phones for measuring everyday items on the go.
This browser-based ruler works on all devices - desktop, tablet, and mobile - without downloads. Switch between inches, centimeters, and millimeters instantly. Toggle horizontal or vertical orientation. Drag to measure any distance. Calibration persists across sessions. No registration required - start measuring immediately.