Practical guides
Pixel & print conversion guides
Practical explanations, worked examples and the assumptions that matter before you resize or print.
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From image pixels to a physical print
Calculate a print size, understand what PPI changes, and keep pixel count separate from physical dimensions.
Read the guidePPI, DPI and CSS pixels are different measurements
Separate image density, printer dots and browser layout units before calculating a size.
Read the guideHow many pixels do you need for a print?
Turn a provider’s PPI requirement into dimensions and understand rounding, crop losses and quality limits.
Read the guideA4 vs US Letter in pixels: rounding and layout differences
Why A4 has no single pixel size, when 2481 beats 2480 at 300 PPI, and what changes when an A4 layout moves to US Letter.
Read the guideFit versus fill: borders or a crop?
See why a photo can have two different effective PPI values at the same finished print size.
Read the guideCheck a local image before you order a print
A practical sequence for checking pixel dimensions, orientation, print size and crop without uploading a photo.
Read the guideAspect ratios, resizing and exact pixel crops
Reduce a ratio, calculate a proportional resize, and choose a centered crop without mixing these operations.
Read the guideCalculate a print scaling percentage with margins
Plan fit and fill between paper sizes while accounting for the usable area on the target sheet.
Read the guidePX to REM, EM and PT: choose the right reference
Work through CSS font and spacing conversions without confusing layout pixels with an image’s print resolution.
Read the guidePX to VW and VH: a worked viewport example
Translate a layout length into viewport units and understand why a mobile browser can change the visible space.
Read the guideA, B, C, Letter and ARCH: find the right paper family
Identify nominal paper dimensions before calculating pixels, especially when similar names describe different standards.
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