Practical guide · dimensions explained
From image pixels to a physical print
Calculate a print size, understand what PPI changes, and keep pixel count separate from physical dimensions.
Reviewed September 28, 2026 · Worked examples calculated for this guide
Illustration of the related tool’s example; proportions only.
Start with the actual pixel dimensions
A file’s width and height in pixels tell you how much image data it contains spatially. Its file size in megabytes does not tell you its print dimensions: compression and image content affect that number. Find the width and height in your image editor, or use the local image checker. Keep the orientation in mind; a 2400 × 3000 image is portrait.
Divide each side by the planned PPI
For a 2400 × 3000 image at 300 pixels per inch, divide 2400 by 300 and 3000 by 300. The result is 8 × 10 inches. Multiplying those inch dimensions by exactly 2.54 gives 20.32 × 25.4 centimeters. At 200 PPI the same file occupies 12 × 15 inches. The pixel count has not changed; the pixels are spread over a larger physical area.
Changing a number is not adding detail
Setting different PPI metadata without resampling changes the relationship between pixels and a proposed print size. Resampling changes pixel dimensions. Enlarging an image through resampling can make more pixels, but a dimensions calculation cannot establish how much useful detail the enlarged image will contain. Our tools plan dimensions; they do not edit the file.
Check the finished shape
An 8 × 10 print has a 4:5 ratio. A 3:2 image cannot fill that shape and also retain every edge without distortion. Decide between borders and a crop before ordering. Use the print checker with your finished size, then inspect important details near the edges. Confirm bleed, margins and file requirements with the actual print provider.
Reference notes
References checked September 28, 2026. Calculations and worked examples are our own.