- What's the formula?
- Inches = pixels ÷ DPI. So 300 pixels at 96 DPI is 300 ÷ 96 = 3.125 inches. Centimeters is just inches × 2.54; millimeters is inches × 25.4. Same math, three units.
- Which DPI should I pick?
- For anything staying on screen: 96 (the CSS reference, also Windows default). 72 is the older Mac screen standard — still shows up in legacy specs but rarely the right pick today. For decent print at home: 150. For magazines, books, and most professional print work: 300. For fine-art prints, archival photo books, or anything examined up close: 600. When in doubt, ask the printer what they want.
- Does 1 pixel always equal 1/96 of an inch?
- In CSS, yes — that's the W3C reference, baked into every modern browser. But the physical pixels on a real screen are usually denser than that, which is why Retina images need 2× or 3× the pixel count to look sharp. For print, the relationship is whatever DPI you tell the printer to use; same image file can print at 4 inches at 300 DPI or 8 inches at 150 DPI.
- What's the difference between DPI and PPI?
- Technically DPI (dots per inch) describes printer dots and PPI (pixels per inch) describes screen pixels. In practice the two terms are used interchangeably and this calculator works identically for both — it's just dividing pixels by a density value to get a physical distance.
- Why doesn't Photoshop's Image Size panel do this for free?
- It does the math correctly, but the panel opens only inside Photoshop, which requires an active Creative Cloud subscription — $22.99/month for the Photography plan, more for the full suite. This calculator does the same arithmetic in your browser, no subscription required, no sign-in, no upload.
- Can I enter decimal pixel values?
- Yes. Modern high-density displays sub-divide pixels routinely, so values like 1.5 px or 2.25 px are meaningful. The calculator handles any positive number, whole or decimal.
- What happens if I set DPI to 0?
- The calculator catches it and asks you to pick a value above zero — dividing by zero would produce nonsense. Try 96 for screen work or 300 for print.
- Is any data sent to a server?
- No. The conversion runs entirely in your browser using JavaScript. Nothing is logged, stored, or transmitted to any third party.
