TV Size Calculator
This TV size calculator tells you what screen size suits your seating distance, or how far to sit from a TV you already have. It works both ways: enter your viewing distance in feet or meters to get a recommended size range in inches, or enter a screen size to get a recommended distance range.
The recommendations come from two widely cited viewing-angle guidelines for 16:9 screens: SMPTE, which suggests the screen fill at least about 30 degrees of your view, and THX, which recommends about 40 degrees for a cinema-like experience. The calculator also shows how close you need to sit to make out every pixel of a 4K or 1080p picture.
TV Size Calculator
How to Use the TV Size Calculator
- 1
Pick a direction
Choose the Distance to TV size tab if you know where the couch goes, or the TV size to distance tab if you already have a TV and want to place your seating.
- 2
Choose feet or meters
Leave the toggle off to enter distance in feet, or switch on Use meters for distance. Screen sizes are always entered in inches, the way TVs are sold.
- 3
Enter your number
Type the distance from your seated eye position to the screen, or the diagonal screen size in inches. Results update as you type.
- 4
Read the range and the chart
Check the SMPTE and THX figures, the common sizes that fit your range, and the 4K note. The chart below the tool lists popular sizes with their recommended distances.
How the TV size calculation works
A viewing-angle guideline describes how much of your horizontal field of view the screen should fill. If you know the angle and the distance, basic trigonometry gives the screen width. For a 16:9 screen the width is about 0.8716 of the diagonal, so dividing the width by 0.8716 gives the diagonal size that TVs are sold by.
Working it backwards, the SMPTE 30 degree guideline puts the viewing distance at about 1.63 times the screen diagonal, and the THX 40 degree guideline at about 1.2 times the diagonal. The calculator uses the exact trigonometry rather than those rounded multipliers.
The 4K and 1080p distances assume 20/20 vision, which resolves detail of about 1 arcminute. The pixel size is the screen height (0.4903 of the diagonal) divided by 2,160 rows for 4K or 1,080 rows for 1080p.
Screen width = 2 x distance x tan(angle / 2); diagonal = width / 0.8716 (16:9). Pixel-visible distance = (diagonal x 0.4903 / rows) / tan(1 arcminute)Worked example: an 8-foot viewing distance
Say your couch is 8 feet (96 inches) from the wall where the TV will hang. Here is what the calculator does with that number.
- SMPTE 30 degrees: width = 2 x 96 x tan(15) = 51.4 in, so the diagonal is 51.4 / 0.8716 = about 59 in
- THX 40 degrees: width = 2 x 96 x tan(20) = 69.9 in, so the diagonal is 69.9 / 0.8716 = about 80 in
- Recommended range: 59 to 80 inches, which includes the common 65, 75 and 77 inch sizes
- To resolve every 4K pixel from 8 feet, the screen would need to be about 123 inches
Worked example: where to sit for a 65-inch TV
Enter 65 in the TV size to distance tab. The THX 40 degree distance is about 6.5 feet (1.98 m) and the SMPTE 30 degree distance is about 8.8 feet (2.69 m), so a seat between roughly 6.5 and 8.8 feet away fits both guidelines. You would need to sit within about 4.2 feet to see every 4K pixel, and within about 8.5 feet to see every 1080p pixel.
TV size to viewing distance chart
All values below come from the same formulas the calculator uses, for 16:9 screens. Sit between the THX and SMPTE columns for a comfortable, immersive picture.
| TV size | THX 40 degrees | SMPTE 30 degrees | Every 4K pixel visible within |
|---|---|---|---|
| 43 in | 4.3 ft (1.31 m) | 5.8 ft (1.78 m) | 2.8 ft |
| 50 in | 5.0 ft (1.52 m) | 6.8 ft (2.07 m) | 3.3 ft |
| 55 in | 5.5 ft (1.67 m) | 7.5 ft (2.27 m) | 3.6 ft |
| 65 in | 6.5 ft (1.98 m) | 8.8 ft (2.69 m) | 4.2 ft |
| 75 in | 7.5 ft (2.28 m) | 10.2 ft (3.10 m) | 4.9 ft |
| 85 in | 8.5 ft (2.59 m) | 11.5 ft (3.51 m) | 5.5 ft |
| 98 in | 9.8 ft (2.98 m) | 13.3 ft (4.05 m) | 6.4 ft |
Tips for choosing a TV size
- Measure from your eyes, not the front edge of the couch. Leaning back on a deep sofa can add a foot or more.
- Most people who upgrade wish they had gone bigger rather than smaller, but a screen past the THX size can feel overwhelming for news and everyday viewing.
- Check the wall or stand width. A 65-inch TV is about 56.7 inches wide and 31.9 inches tall before the bezel and stand.
- Mount the screen so its center is near seated eye level. A TV high over a fireplace strains your neck no matter what size it is.
- A 4K TV is still worth it beyond the pixel-visible distance. You get better color, HDR and streaming quality even if you cannot see individual pixels.
Features
- Viewing distance to recommended TV size range
- TV size to recommended viewing distance
- SMPTE 30° and THX 40° viewing-angle guidelines
- 4K and 1080p pixel-visibility distances
- Feet or meters for distance
- TV size and viewing distance chart
Frequently Asked Questions
What size TV should I get for my room?
Start with the distance from your seat to the screen. Using the SMPTE 30 degree and THX 40 degree guidelines, multiply your distance in inches by about 0.61 for the minimum size and 0.84 for the cinematic size. At 8 feet (96 inches) that is roughly 59 to 80 inches, so a 65 or 75 inch TV is a good fit.
How far should you sit from a 65-inch TV?
For a 16:9 65-inch TV, the THX 40 degree guideline gives about 6.5 feet (1.98 m) and the SMPTE 30 degree guideline about 8.8 feet (2.69 m). Sitting anywhere between those distances gives a large, comfortable picture. To see every individual 4K pixel with 20/20 vision you would need to sit within about 4.2 feet.
What is the THX recommended viewing distance?
THX recommends that the screen fill about 40 degrees of your horizontal field of view for a cinema-like experience. For a 16:9 screen that works out to a viewing distance of about 1.2 times the diagonal. A 75-inch TV, for example, would be viewed from about 7.5 feet. The SMPTE guideline of 30 degrees is less immersive, at about 1.63 times the diagonal.
Is 4K worth it if I sit far from the TV?
The sharpness advantage of 4K shrinks with distance. With 20/20 vision you can resolve every 4K pixel on a 65-inch screen only within about 4.2 feet, and every 1080p pixel within about 8.5 feet. Beyond that, extra resolution is harder to see, but 4K TVs also bring HDR, wider color and better streaming bitrates, so they are still the practical choice.
Is a 75-inch TV too big for an 8-foot distance?
No. At 8 feet the THX 40 degree guideline works out to about an 80-inch screen and the SMPTE 30 degree guideline to about 59 inches. A 75-inch TV sits near the immersive end of that range. If you mostly watch news or sports casually, a 65-inch set is also within the recommended range.
Does this calculator work for ultrawide or 4:3 screens?
No, the math assumes a 16:9 screen, which is the shape of almost every TV sold today. For other aspect ratios the width-to-diagonal ratio changes, so the same diagonal gives a different width and viewing angle. For a projector screen in 16:10, 4:3 or 2.35:1, use a projector throw calculator that handles aspect ratios.
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