PPI Calculator
Runs entirely in your browser - no upload, no sign-up.
Display details
Resolution and physical size
Use the native pixel resolution and the measured or advertised corner-to-corner diagonal.
Live result
Pixel density and dimensions
Pixels per inch163.18PPI
3840 x 2160
Physical width x height23.53 x 13.24 in
Width x height in centimeters59.77 x 33.62 cm
Diagonal resolution4,406 px
Total resolution8.29 MP
What is a PPI calculator?
A PPI calculator finds pixel density from a screen or image resolution and its physical diagonal size. Enter the horizontal pixels, vertical pixels and diagonal in inches or centimeters to get pixels per inch, pixel pitch, physical width and height, diagonal pixels, megapixels and aspect ratio instantly.
How to use
- 1Enter the resolution. Type the native horizontal and vertical pixel dimensions, such as 3840 x 2160.
- 2Add the physical diagonal. Enter the corner-to-corner display or image size and choose inches or centimeters.
- 3Read the live results. Check PPI, display DPI equivalent, pixels per centimeter, pixel pitch and physical width and height.
- 4Copy the measurements. Copy the complete result summary for a specification sheet, comparison or project note.
Who it's for
- Monitor buyers comparing how tightly 1080p, 1440p and 4K pixels are packed at different screen sizes.
- Designers and developers checking physical pixel size, display density and real panel dimensions for interface or kiosk work.
- Photographers and print makers estimating the pixel density an image will have at a chosen physical size.
- Hardware reviewers verifying manufacturer PPI claims from native resolution and diagonal measurements.
The calculator first finds the diagonal pixel count with the Pythagorean theorem: sqrt(width^2 + height^2). It divides that value by the physical diagonal in inches to get pixels per inch. All calculations run locally in your browser, and no dimensions are uploaded.
FAQ
Is this PPI calculator free?
Yes. The calculator is free to use, requires no account and has no usage limit. It updates as you type and includes PPI, pixel pitch, physical dimensions, megapixels and aspect ratio in one result.
Are my display dimensions uploaded?
No. The calculator runs entirely in your browser. The resolution and physical size you enter stay on your device and are not sent to a server.
What is the difference between PPI and DPI?
PPI measures pixels per inch in a digital image or display. DPI measures printed dots per inch. People often say screen DPI when they mean PPI, so the calculator shows the same numeric value as a display DPI equivalent while keeping the terms distinct.
How do you calculate screen PPI?
Find diagonal pixels with sqrt(width squared + height squared), then divide by the physical diagonal in inches. A 3840 x 2160 display has about 4405 diagonal pixels, so a 27-inch panel is about 163.18 PPI.
Does display scaling change PPI?
No. PPI is a physical property of the panel, based on native pixels and physical size. Windows scaling, macOS scaling, browser zoom and device pixel ratio change how software maps interface pixels, but the hardware pixel density stays the same.
What limits does the calculator have?
Pixel width and height must be positive whole numbers up to one billion. The diagonal can be a decimal in inches or centimeters. Accuracy depends on using the native resolution and the actual viewable diagonal, which may differ slightly from a marketed size.