Convert pixel dimensions to physical size in cm, mm and inches at any DPI/PPI. Includes a bleed allowance for print prep.
Built and maintained by Paul Clark, Redmoon Software · Checked against what this tool computes on
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Inches = pixels ÷ DPI. cm = inches × 2.54. mm = inches × 25.4. Bleed is added to all four edges; the trim box stays the input size, the bleed box is larger.
Reverse: pixels = inches × DPI. For print, 300 DPI is the floor for crisp text; 150 is acceptable for posters viewed at distance.
The conversion is direct: inches = pixels ÷ DPI, then cm = inches × 2.54 and mm = inches × 25.4. Reverse the direction and pixels = inches × DPI, rounded to a whole number. The DPI dropdown offers 72 (legacy web), 96 (web standard, the default), 150 (draft print), 300 (offset print), 600 (fine art) and Custom, which enables the otherwise-disabled custom field for any value from 1 to 2400.
DPI changes the answer more than anything else: the same 1920 × 1080 image measures 50.80 × 28.58 cm at 96 DPI but only 16.26 × 9.14 cm at 300. Set it to match the destination, using 300 for anything printed and read close up, and 150 for posters viewed at a distance. The Bleed (mm) field adds its value to all four edges, so the trim size stays exactly as entered and separate with-bleed rows appear.
DPI is only metadata on a screen image, since a file has no physical size until you assign one, so this tells you what an image can print at cleanly rather than what it already measures. Nothing checks whether upscaling would degrade quality: ask for 300 DPI on a small photo and it reports a large pixel requirement you may not be able to meet. There is no safe-zone or margin feature, only bleed, and no colour-profile handling.
Click the A4 @ 300dpi preset: 21 × 29.7 cm converts to 2480 × 3508 pixels. That is the trim size only. Add 3 mm of bleed and the requirement rises, with the extra with-bleed pixel row appearing at the bottom of the table.
At the default 96 DPI it is 50.80 × 28.58 cm, and the 1920×1080 @ 96dpi preset sets that up in one click. Change the DPI and the answer scales inversely: at 300 DPI the identical file measures just 16.26 × 9.14 cm.
The help text names 3 mm as the standard, and the field accepts 0 to 20 mm in half-millimetre steps. The value is applied to every edge, so 3 mm adds 6 mm to both width and height in the with-bleed rows while the trim measurement stays unchanged.
96 is the modern web standard and this tool's default, while 72 is the legacy value kept for older workflows. Either is harmless for screen work because browsers ignore the embedded figure; it only starts to matter once a file is placed into a print layout.
The Business card @ 300dpi preset uses 8.5 × 5.5 cm, the common European size, which converts to 1004 × 650 pixels at 300 DPI. Enter 3 mm in the bleed field if your printer requires it before you export the artwork.
An image of 1,000 pixels is not any physical size. It becomes one when a resolution is applied: at 96 dpi it is about 10.4 inches, at 300 dpi about 3.3, at 600 about 1.7. The pixel count did not change — only the decision about how densely to place them.
That is why "how big is this image" has no answer without a target medium, and why resizing for print and resampling are different operations. Changing dpi without resampling changes the physical size and touches no pixels; resampling changes the pixel count and invents or discards data.
The presets cover the common cases: 72 and 96 dpi are screen conventions of historical origin rather than measurements of any actual display, 150 is adequate for large-format work viewed at distance, 300 is the standard for commercial print, and 600 for line art and text where edge sharpness matters more than tonal detail.
Viewing distance is the variable that justifies going lower. A billboard is frequently produced at well under 50 dpi because nobody stands a foot from it, and printing it at 300 would be an enormous file for no visible gain.
Screens complicate this further, since device pixel ratio means a CSS pixel and a hardware pixel are not the same thing on most modern displays.
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