How to use the PPI Calculator
Enter the pixel size
Width and height start at 2560 and 1440.
Type any field
Change the width, the height, or the diagonal in inches. PPI updates as you type.
Read the density
The big number is pixels per inch for that panel.
Summarize with
Pixel density formula
PPI = √(W²+H²) / d. 2560×1440 at 27 inches is ≈ 108.8. The same 1440p on a 32 inch 16:9 panel is lower PPI.
This page does not claim a specific phone PPI without a manufacturer citation. Enter the official resolution and viewable diagonal yourself.
PPI versus DPI
A PPI calculator describes a glowing panel. DPI describes a print command. The two pages stay separate so a print lab and a monitor shopper do not share one form.
Use the PPI calculator again when you change the diagonal and want the new density without retyping the ratio.
Common mistakes
Using advertised “screen size” that includes speakers.
Comparing PPI across different viewing distances as if it were sharpness in the abstract.
Why this page is not the DPI tool
PPI starts from a glowing rectangle and a diagonal. DPI starts from paper inches. 2560×1440 at 27 inches is about 108.8 PPI; 8×10 at 300 DPI is 2400×3000 pixels. Mixing the two units is the most common support email we expect after launch.
We omit branded phone PPI tables on purpose. Enter the official resolution and viewable diagonal yourself so a stale device row cannot lie.
Why phones are omitted
Phone PPI tables rot every autumn. The PPI Calculator asks you for the official resolution and the viewable diagonal from the manufacturer’s spec sheet. 2560×1440 at 27 inches remains the worked fixture because that desktop pair is stable.
Do not compare PPI across a phone at 12 inches viewing distance and a TV at 3 metres as if the number were sharpness in the abstract. Density is pixels per inch, not perceived acuity.
Frequently asked questions
What is a PPI calculator?
It reports pixels per inch from resolution and diagonal.
What is 2560×1440 at 27 inches?
About 108.8 PPI.
Is PPI the same as DPI?
No. Use the DPI to pixel tool for print.
Does aspect ratio matter?
Only to check that W and H match the panel. The PPI formula uses both.
Why not list iPhone PPI?
Device tables go stale; we omit them until cited.