5 Screen Size Comparison Secrets Retailers Hide
When you see "6.7-inch screen" on a phone box or "55-inch TV" on a store display, you assume you know what you are getting. But retailers and manufacturers use a specific set of measurement tricks that make screens appear larger on paper than they actually are in your hand or living room. Here are the five biggest secrets they do not want you to know — and how to compare screen sizes accurately.
Secret #1: Diagonal Measurement Ignores Aspect Ratio
Screen sizes are always measured diagonally, from one corner to the opposite corner. But two screens with the same diagonal can have very different actual screen areas depending on their aspect ratio.
For example, a 6.7-inch phone screen with a 19.5:9 aspect ratio (tall and narrow) has a different usable area than a 6.7-inch screen with a 20:9 ratio. The difference can be up to 5% in total screen area — which you will notice when reading text or watching videos.
This is why our visual comparison tool shows screens at real scale with accurate proportions, so you see the actual difference rather than just a diagonal number. Learn more about this in our screen area vs diagonal guide.
Secret #2: Bezel Size Hides the Real Phone Size
Two phones with the same screen diagonal can have completely different physical dimensions because of bezels and screen-to-body ratio. A phone with thin bezels and a 6.7-inch screen might be smaller in your hand than a phone with thick bezels and a 6.5-inch screen.
| Phone | Screen Size | Phone Width | Screen-to-Body |
|---|---|---|---|
| Samsung Galaxy S25 Ultra | 6.9" | 77.6 mm | 89.3% |
| iPhone 16 Pro Max | 6.9" | 77.6 mm | 88.3% |
| Samsung Galaxy S25+ | 6.7" | 75.5 mm | 88.5% |
| iPhone 16 | 6.1" | 71.6 mm | 86.3% |
Notice how the Galaxy S25+ at 6.7 inches is narrower than both 6.9-inch phones. Screen-to-body ratio matters more than raw diagonal size when it comes to how a phone feels in your hand. Try comparing phones side by side with our Galaxy S25+ vs S25 Ultra comparison or iPhone 16 vs 16 Plus comparison.
Secret #3: TV Screens Are Smaller Than Advertised
A "55-inch TV" is almost never exactly 55 inches diagonal. Most TV screens measure 54.5 to 54.6 inches diagonally. The industry standard allows a tolerance of roughly 0.5 inches, and manufacturers consistently round up. This means a "55-inch" TV might actually be closer to 54.5 inches — and the total screen area could be 1-2% smaller than you expect.
The difference grows with size. A "75-inch" TV might actually be 74.5 inches, which translates to a meaningful area difference. When comparing two TVs that are close in size (like 50 vs 55 inches), the real difference might be less than the advertised numbers suggest. See our how big is a 55-inch TV guide for exact measurements.
Secret #4: Resolution Makes the Same Size Feel Different
Two screens with the same physical size but different resolutions create completely different experiences. A 6.7-inch phone screen at 1080p (FHD+) has a pixel density of about 390 PPI. The same 6.7-inch screen at 1440p (QHD+) has about 520 PPI.
Higher pixel density means:
- Crisper text when reading books or articles
- Sharper images in photos and social media
- Better detail in fine print and UI elements
- However, the difference between 390 PPI and 520 PPI is barely visible to most people at normal phone viewing distances
Retailers love to advertise "4K" on phones because it sounds premium, but the visible difference between FHD+ and QHD+ on a 6.7-inch screen is minimal. You are paying for specs you cannot see. Read more in our screen resolution explained guide.
Secret #5: Curved Screens Count the Curve
Curved screen phones (like older Samsung Galaxy Edge models) measure the diagonal along the curved surface, not as a flat projection. This means the flat-screen area you actually see is smaller than the advertised diagonal suggests.
On a phone with a strongly curved display edge, up to 5% of the screen area is on the curved portion that distorts content and is difficult to use for touch interactions. So a "6.7-inch curved screen" gives you less usable flat area than a "6.7-inch flat screen."
The industry has mostly moved away from extreme curves in 2025-2026, but the measurement practice persists. When comparing screen sizes, always consider whether the screen is flat or curved. See our curved vs flat monitor comparison for how this affects larger displays too.
How to Compare Screen Sizes Accurately
Now that you know the tricks, here is how to cut through the marketing:
- Compare actual screen area, not just diagonals. A 6.3 vs 6.9 inch comparison shows a 30% area difference, not the 10% the diagonal numbers suggest.
- Check the physical dimensions of the device. Two phones with the same screen size can differ by 5-10mm in width.
- Factor in screen-to-body ratio. Higher ratios mean more screen and less wasted space.
- Use a visual comparison tool. Our screen comparison tool overlays screens at true scale so you see the real difference.
- Consider resolution and pixel density together. Higher resolution on the same size screen matters most for reading and fine detail.
The Bottom Line
Screen size numbers are a starting point, not the full picture. Diagonal measurements, bezels, aspect ratios, and curved surfaces all conspire to make screens appear larger on spec sheets than in reality. The best way to know if a screen size is right for you is to compare sizes visually before you buy. For more insights, check our guides on common comparison mistakes and screen size myths.