Frame Rate Test

Retina Display Calculator

Retina threshold: 60 pixels per degree (1′ per pixel).

Display Specs

Resolution (pixels)
×
Screen size (diagonal inches)

Results

Pixel density (PPI)
108.8
pixels per inch
Retina distance
80
cm — pixels vanish at or beyond this
Pixels / cm
42.8
Screen width
59.8 cm
Screen height
33.6 cm
Screen area
2,010 cm²
Aspect ratio
16:9
Diagonal
2,937 px
Total pixels
3.7 MP
Dot pitch
0.2335 mm
Resolution
2,560 × 1,440

Is your display Retina at your viewing distance?

Enter how far you sit from the screen to see whether you can resolve individual pixels.

Not quite Retina

At 80 cm you need about 109 PPI for a retina image, and your display has 109 PPI. Sit at least 80 cm away to stop seeing pixels.

That is about 60 pixels per degree (1 arcmin/pixel). Your retina threshold is 60 PPD.

How it compares to Apple Retina displays

iPhone (Retina)
326 PPI
Retina at 27 cm (11")
iPad (Retina)
264 PPI
Retina at 33 cm (13")
MacBook Pro (Retina)
227 PPI
Retina at 38 cm (15")
iMac 5K (Retina)
218 PPI
Retina at 40 cm (16")

Use this retina display calculator to find your screen's PPI (pixels per inch), retina pixel density, and the retina viewing distance where individual pixels disappear. It doubles as a display resolution calculator and monitor dimensions calculator — enter any resolution and screen size to calculate screen resolution details, retina display PPI, aspect ratio, and the real physical width and height of your monitor. You can also compare two displays side by side or work backwards from a viewing distance to the right TV or monitor size.

How the Retina Display Calculator Works

Apple coined the term “Retina display” for screens whose pixels are so densely packed that, at a normal viewing distance, your eye cannot make out the individual pixels. This PPI calculator turns that idea into exact numbers. First it acts as a display resolution calculator, deriving the pixel density from your resolution and screen size: PPI is the diagonal in pixels divided by the diagonal in inches. Then it converts that retina PPI into a retina distance using the eye's roughly one-arcminute limit, so you know exactly how far to sit for a flawless image.

What This Tool Calculates

Retina PPI & Pixel Density

A full PPI calculator screen readout: the retina display PPI and retina pixel density for any resolution and size, so you can compare how sharp two monitors really are.

Retina Viewing Distance

The minimum distance for a pixel-free, retina image, plus a checker that tells you whether your screen is retina at your actual seating distance.

Monitor Dimensions

A monitor dimensions calculator and display size calculator in one — it will calculate monitor dimensions (physical width and height) in inches and centimetres from the diagonal and resolution.

Resolution & Aspect Ratio

Acting as a monitor resolution calculator, it reports total megapixels, aspect ratio, and dot pitch to help you calculate screen resolution details at a glance.

Retina Distance Chart for Common Displays

An HD distance chart of popular monitors, laptops, and TVs showing the resolution for a retina display and how far away each one becomes pixel-free. Distances assume 20/20 vision (1 arcminute).

DisplayResolutionPPIRetina distance
13" laptop, Full HD1920 × 108016653 cm (21")
15.6" laptop, Full HD1920 × 108014162 cm (24")
24" monitor, Full HD1920 × 10809295 cm (37")
27" monitor, Full HD1920 × 108082107 cm (42")
27" monitor, QHD 1440p2560 × 144010980 cm (32")
32" monitor, QHD 1440p2560 × 14409295 cm (37")
34" ultrawide, 3440×14403440 × 144011080 cm (31")
27" monitor, 4K UHD3840 × 216016354 cm (21")
32" monitor, 4K UHD3840 × 216013863 cm (25")
43" display, 4K UHD3840 × 216010285 cm (34")
55" TV, 4K UHD3840 × 216080109 cm (43")
65" TV, 4K UHD3840 × 216068129 cm (51")
75" TV, 4K UHD3840 × 216059149 cm (59")
65" TV, 8K7680 × 432013664 cm (25")

The Formulas

PPI
√(w² + h²) ÷ diagonal
Retina distance
≈ 8732 ÷ PPI (cm)
Monitor width / height
w ÷ PPI  ·  h ÷ PPI

Frequently Asked Questions

A retina display calculator works out the pixel density (PPI) of a screen and the distance at which it becomes a "retina" display — the point where your eye can no longer pick out individual pixels. Enter your resolution and screen size and this retina calculator instantly returns the retina PPI, the retina viewing distance, the aspect ratio, and the physical monitor dimensions.
PPI = √(width² + height²) ÷ diagonal size in inches. For example, a 27-inch 2560 × 1440 monitor has a diagonal of √(2560² + 1440²) ≈ 2937 pixels, so its PPI is 2937 ÷ 27 ≈ 109. This PPI calculator does the math for you for any screen resolution and size, including retina display PPI and general retina pixel density.
The retina distance is the closest you can sit before individual pixels become visible. It is based on the eye resolving roughly one arcminute (1/60°) of detail: retina distance (inches) = 1 ÷ (PPI × tan(1 arcminute)), which is about 3438 ÷ PPI inches, or roughly 8732 ÷ PPI centimetres. A higher PPI means you can sit closer and still see a perfectly sharp, pixel-free image.
Once you know the PPI, the physical width is the horizontal resolution ÷ PPI and the height is the vertical resolution ÷ PPI. This doubles as a monitor dimensions calculator and display size calculator: enter the diagonal and resolution and it returns the real width and height of the panel in inches and centimetres, so you can calculate monitor dimensions before you buy or mount a screen. If you only need physical size from an aspect ratio (no resolution), use the screen size calculator.
There is no single PPI that makes a screen "retina" — it depends on how far away you sit. A 27-inch 4K monitor (about 163 PPI) is retina from roughly 53 cm away, which is normal desk distance, while the same resolution on a 55-inch TV is retina only from over a metre away. Use the viewing-distance checker above to compare your display's PPI with the PPI you need at your seating distance.
Work backwards from your viewing distance: required PPI = 1 ÷ (distance in inches × tan(1 arcminute)). Multiply that PPI by your screen's physical width and height to find the resolution for a retina display. The calculator shows the required PPI for any distance, so you can pick a screen resolution that stays sharp where you actually sit.
Pixels per degree (PPD) measures how many pixels fall within one degree of your field of view, so it depends on both pixel density and how far away you sit. A display looks retina at roughly 60 PPD — the 20/20-vision limit of about one arcminute per pixel. The viewing-distance checker above reports the PPD at your distance so you can see how much headroom you have above or below the 60 PPD retina threshold.
Switch to the Distance → Size tab and enter how far your sofa is from the screen. Using the THX (40°) immersive and SMPTE (30°) comfortable viewing-angle standards, the calculator recommends a diagonal size range and shows whether 1080p, 4K, or 8K stays retina-sharp at that distance. As a rule of thumb, a 4K TV around 65–75 inches suits a 3-metre (about 10-foot) living-room distance.
Yes. Switch to the Compare two tab and enter each display's resolution and screen size. The calculator lists their PPI, pixel density, retina distance, dimensions, aspect ratio, and dot pitch side by side, then tells you which display is sharper and by how much — handy when choosing between two monitors, laptops, or TVs.
The standard retina threshold assumes 20/20 vision, where the eye resolves about one arcminute of detail (60 pixels per degree). Some people see more sharply, so you can switch the visual-acuity setting to 0.6 arcminutes (100 PPD, DisplayMate's stricter standard) or 0.4 arcminutes. A stricter setting demands more PPI and a longer retina distance, and every retina verdict updates to match.
Display resolution is the total number of pixels (for example 3840 × 2160), while PPI is how tightly those pixels are packed into each physical inch. Two screens can share a resolution but have very different PPI if their sizes differ. This display resolution calculator reports both, plus aspect ratio and dot pitch, so you can compare sharpness fairly across monitors of different sizes.

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