How to Compare Screen Sizes Accurately (2026) | Easy Compare

Comparing screen sizes should be straightforward — bigger number means bigger screen, right? Not quite. A 27-inch 16:9 monitor and a 27-inch 21:9 ultrawide have the same diagonal but vastly different shapes. A 6.7-inch phone can feel bigger or smaller than expected depending on bezels and aspect ratio. In this guide, we walk through five proven methods to compare screen sizes accurately, so you never make a misinformed purchase again.

For instant, visual results, try the Easy Compare screen comparison tool — it shows any two screens at true-to-life scale, side by side.

Method 1: Calculate True Screen Area

The diagonal measurement alone tells you almost nothing about how much screen you actually get. Two screens with the same diagonal can differ by up to 20% in total area depending on their shape. Here is how to calculate the real area:

Formula for a 16:9 screen: Area = (diagonal ² × 16 × 9) / (16² + 9²) = diagonal² × 0.4273

Notice: the ultrawide has 13% less area than the standard 16:9 despite the same 27-inch diagonal. Always compare area, not just diagonal inches.

Method 2: Factor in Aspect Ratio

Aspect ratio determines the shape of your screen, and it matters more than most people realize. A wider screen (21:9) gives you horizontal space for timelines and side-by-side windows, while a taller screen (16:10 or 3:2) gives you more vertical space for documents, code, and web browsing.

• 16:9 — The standard for movies, TV, and most monitors. Good all-around choice.
• 16:10 — Popular on productivity monitors and MacBooks. Extra vertical space helps with documents and code.
• 21:9 — Ultrawide format. Great for video editing timelines and gaming immersion, but less total area than 16:9 at the same diagonal.
• 3:2 — Used on Surface devices and some laptops. Balances width and height well for productivity.
• 19.5:9 or 20:9 — Modern phone aspect ratios. Taller and narrower, optimized for scrolling and one-handed use.

When you compare screen sizes, always note the aspect ratio. Two screens at the same diagonal but different aspect ratios serve completely different purposes. Use our guide on what screen comparison charts miss for a deeper dive.

Method 3: Check Pixel Density (PPI)

A larger screen at low resolution can look worse than a smaller screen at high resolution. Pixel density (PPI) — pixels per inch — determines how sharp text and images appear. Two screens with the same diagonal size but different resolutions will look dramatically different.

Guideline: Phones should have 300+ PPI, monitors 100+ PPI for comfortable reading, and TVs can be lower because you sit further away. For more on this topic, see our screen resolution guide.

Method 4: Use a Visual Comparison Tool

Numbers and formulas are helpful, but nothing beats seeing screens side by side at true scale. A visual comparison tool eliminates the guesswork by rendering both screens proportionally on your display.

Here is why visual comparison matters:

• Human brains are bad at comparing diagonal measurements. Most people cannot intuitively translate "6.7 inches diagonal" into a mental image of the actual screen.
• Aspect ratio differences become obvious immediately. When you see a 16:9 and 21:9 screen next to each other, the shape difference is undeniable.
• Area differences are visible at a glance. Instead of calculating area with formulas, you can simply see which screen is bigger.
• Device context matters. Seeing a phone screen next to a tablet screen helps you understand the real-world size jump.

The Easy Compare tool lets you pick any two devices or enter custom dimensions, then renders them at true scale. It is the fastest way to compare screens accurately.

Method 5: Measure Physical Dimensions

Screen size (the diagonal) is only part of the story. The physical device dimensions — width, height, depth, and weight — determine how a screen fits into your life:

• Phones: Two phones with 6.7-inch screens can differ in overall size by up to 10% depending on bezels. Always check the full device dimensions, not just the screen diagonal.
• Monitors: A 27-inch monitor with a thick plastic bezel takes up more desk space than a 27-inch monitor with thin bezels. Check the "dimensions with stand" specification.
• TVs: TV depth varies significantly between OLED (ultra-thin) and LED/LCD models. Wall-mounting considerations depend on full dimensions, not screen size alone.
• Laptops: A 15.6-inch laptop can weigh anywhere from 3 to 6 pounds. The screen size does not tell you about portability.

For a complete reference on how screen sizes translate to physical dimensions, check our how big is a 27-inch monitor guide as an example.

Quick Reference: Screen Comparison Checklist

Before your next screen purchase, run through this checklist:

Compare Any Two Screens Now

Stop guessing and start comparing. The Easy Compare screen comparison tool handles all the calculations for you — just pick your two devices and see them at true scale. It works for phones, tablets, monitors, laptops, and TVs.

Popular comparisons to try:

• iPhone 16 Pro vs Pro Max — see the real size difference between 6.3 and 6.9 inches
• Galaxy S25+ vs S25 Ultra — 6.7 vs 6.9 inch Samsung flagship comparison
• iPad Pro 11 vs 13 inch — tablet size comparison at true scale
• 55 vs 65 inch TV — see how much extra screen you get with 10 more inches