Display and Scaling Calculator
Screen size and resolution give you pixel density, the scaling percentage that actually fits, and the desktop space each step leaves you.
- Pixel density
- 163.2 PPI
- Recommended scaling
- 150%
- Desktop space
- 2560 × 1440
- Dot pitch
- 0.156 mm
- Sharpness
- 68 px/deg
Past what the eye resolves
A 20/20 eye cannot separate single pixels from this distance. A 20/20 eye stops resolving single pixels on this panel from 21.1 inches (54 cm) away.
The panel is 23.53 by 13.24 inches, 16:9, at 163.18 pixels per inch.
Every scaling step on this screen
What each Windows scaling percentage leaves you, on the numbers above.
| Scaling | Desktop space | Effective density | Area against native |
|---|---|---|---|
| 100% | 3840 × 2160 | 163.2 PPI | 100% |
| 125% | 3072 × 1728 | 130.5 PPI | 64% |
| 150%Recommended | 2560 × 1440 | 108.8 PPI | 44% |
| 175% | 2194 × 1234 | 93.2 PPI | 33% |
| 200% | 1920 × 1080 | 81.6 PPI | 25% |
| 225% | 1706 × 960 | 72.5 PPI | 20% |
| 250% | 1536 × 864 | 65.3 PPI | 16% |
| 300% | 1280 × 720 | 54.4 PPI | 11% |
Common panels and what they want
Pixel density and the scaling that fits, at a 24-inch desk distance.
| Panel | Resolution | Density | Scaling | Desktop space |
|---|---|---|---|---|
| 21.5-inch 1080p | 1920 × 1080 | 102 PPI | 100% | 1920 × 1080 |
| 24-inch 1080p | 1920 × 1080 | 92 PPI | 100% | 1920 × 1080 |
| 27-inch 1440p | 2560 × 1440 | 109 PPI | 100% | 2560 × 1440 |
| 27-inch 4K | 3840 × 2160 | 163 PPI | 150% | 2560 × 1440 |
| 32-inch 4K | 3840 × 2160 | 138 PPI | 125% | 3072 × 1728 |
| 34-inch ultrawide 1440p | 3440 × 1440 | 110 PPI | 100% | 3440 × 1440 |
| 49-inch super ultrawide | 5120 × 1440 | 109 PPI | 100% | 5120 × 1440 |
| 13.3-inch 1600p laptop | 2560 × 1600 | 227 PPI | 200% | 1280 × 800 |
| 15.6-inch 1080p laptop | 1920 × 1080 | 141 PPI | 125% | 1536 × 864 |
| 55-inch 4K TV | 3840 × 2160 | 80 PPI | 100% | 3840 × 2160 |
How it works
The arithmetic
Pixel density is the pixel diagonal divided by the physical diagonal. A 3840 by 2160 panel has a pixel diagonal of 4406, so a 27-inch one is 163 pixels per inch and a 32-inch one is 138. The physical width and height come out of the same triangle, which is why this page can tell you a 27-inch 16:9 screen is 23.5 inches wide before you measure it.
Which scaling actually fits
A Windows desktop is comfortable at roughly 109 effective pixels per inch, which is a 27-inch 1440p screen at 100%. Every scaling step is judged against that: the panel density divided by the step, compared with the target on a ratio rather than a difference, so overshooting and undershooting count the same. That is the row marked recommended. Every other step is in the table with what it costs you in desktop space, because the recommendation is about text size and nothing else.
Viewing distance
Distance changes both answers. Sitting twice as far away halves the apparent size of everything, so the target density halves with it and the recommended step goes up. The default is 24 inches, a normal desk. Sharpness is reported in pixels per degree of vision, which is density and distance in one number. Around 60 pixels per degree a 20/20 eye stops separating single pixels, which is where the page stops calling a screen sharper.
What this page does not do
It assumes square pixels and a flat panel, so a curved screen is measured along its arc and reads very slightly dense. It knows nothing about subpixel layout, so an OLED with an unusual arrangement will look softer than its density says. And it is arithmetic, not a measurement: Read my screen reads what the browser reports, which browser zoom can move.
Questions
Does a 27-inch 4K monitor need 150% scaling?
At a normal desk distance, yes. A 27-inch 3840 by 2160 panel is 163 pixels per inch, and 150% brings that down to an effective 109, which is the same apparent size as a 27-inch 1440p screen at 100%. You are left with 2560 by 1440 of desktop space. 125% is a common choice for people who want more room on screen and do not mind smaller text.
What is a good PPI for a desktop monitor?
Between about 90 and 110 pixels per inch, everything on a Windows desktop is the size it was designed to be at 100% scaling, so nothing needs scaling at all. That is 24-inch 1080p, 27-inch 1440p and 32-inch 4K at 125%. Below 90 the pixels are visible from a desk. Above 130 you need scaling, which is fine, but it means you are buying sharpness rather than desktop space.
Does scaling make things blurry?
Scaling itself does not. Windows draws modern applications at the scaled size directly, so text gets sharper as the scaling and the density go up together. Older applications that cannot scale are stretched instead, and those look soft. Fractional steps such as 125% and 175% show it most, because a one pixel line has to land somewhere.
Why does Read my screen report a different resolution than my monitor?
The browser reports the logical desktop, so this page multiplies it by the device pixel ratio to get back to native pixels. Browser zoom moves that ratio too, so read it at 100% zoom. On a multi-monitor setup it reports the screen this window is on, and some browsers report the primary screen instead.