How to Measure Monitor Size

What You'll Need

• Measuring tape or ruler (preferably in inches and centimeters)
• Pen and paper for recording measurements
• Calculator (optional)

Method 1: Measuring Diagonal Size

Monitor size is traditionally measured diagonally, corner to corner:

1. Identify the visible screen area: Don't include the bezel/frame
2. Place measuring tape at bottom-left corner of visible screen
3. Extend to top-right corner (or bottom-right to top-left)
4. Record the measurement in inches

Important: Measure only the lit display area, not the plastic frame around it.

Converting Centimeters to Inches

If your ruler shows centimeters, divide by 2.54:

Example: 68.6 cm ÷ 2.54 = 27 inches

Method 2: Manufacturer Specifications

Check the model number sticker (usually on the back) or look up specs online:

1. Find model number (e.g., "Dell U2723DE")
2. Search "[model number] specifications"
3. Look for "Screen Size" or "Display Diagonal"

Note: Manufacturer specs may round (27" might be 27.2" actual)

Calculating Width and Height

If you know diagonal and aspect ratio, calculate dimensions:

For 16:9 aspect ratio:

• Width = Diagonal × 0.8716
• Height = Diagonal × 0.4903

Example for 27" 16:9 screen:

• Width = 27 × 0.8716 = 23.5"
• Height = 27 × 0.4903 = 13.2"

Method 3: Using Our Calculator

The easiest method: Use our Screen DPI Calculator with credit card calibration. It automatically determines your screen's physical dimensions without manual measurement.

Common Screen Sizes

Calculating Screen Area

Multiply width × height for total screen area:

27" monitor (23.5" × 13.2") = 310 square inches

Tips for Accurate Measurement

• Use a flexible measuring tape for curved screens
• Measure twice to verify accuracy
• Record measurements immediately to avoid forgetting
• Round to nearest 0.1 inch for precision