Digital Image Resolution Converter
Convert pixel and dot density values between per-inch, per-centimeter, per-millimeter, and per-meter units.
Converter guide
About Digital Image Resolution Converter
Digital image resolution can describe pixel density or print-dot density over a physical length. This converter changes supported density values between common units such as pixels per inch and pixels per centimeter. It converts the scale; it does not add pixels to an image.
How to use this converter
- 1Enter a resolution or density value from an image, scanner, printer, or layout setting.
- 2Select its current unit and the target density unit, checking that both use the same kind of measure.
- 3Read the converted density and separately check pixel dimensions and intended print size if you are preparing an image for output.
Conversion method and technical details
Density units describe a count per unit length. Conversion changes the length basis; for example, one inch is 2.54 centimeters, so pixels per inch and pixels per centimeter differ by that factor. A density tag alone does not change the raster's pixel width or height.
Worked real-world example
300 pixels per inch is about 118.11 pixels per centimeter. If an image is 1,200 pixels wide, its printed width at 300 PPI is four inches regardless of this unit conversion.
Common scenarios and use cases
Translate scanner, printer, image-editor, and print-layout density values between metric and customary units.
For a dependable comparison, confirm both unit labels, keep the original measurement with the converted value, and use the precision required by the task. The converter changes the representation of a value; it does not measure the item or decide which standard your project requires.
Important details and limitations
PPI and DPI are often used loosely, though pixels and printer dots are not always the same thing. Print size depends on pixel dimensions and output density; image quality also depends on source detail and resampling.
Check the output unit as well as the number. If the result will be reused in another calculation, retain full precision where possible and round only at the end. For measurements governed by a technical specification, use the standard and tolerance required by that document.
Frequently asked questions
Does changing PPI add image detail?
No. It changes a density value; adding pixels requires resampling and cannot recreate missing detail.
Are PPI and DPI identical?
They are related density terms but can describe different stages of digital image and print output.
How wide is a 1,200-pixel image at 300 PPI?
Four inches, before any cropping or scaling.
Why can the converted number look much larger or smaller?
Different units use different scales. A measurement can have a larger number in a smaller unit and still describe the same quantity. Check the source and target unit labels before comparing values.
How many decimal places should I keep?
Keep enough precision for the job and avoid rounding values between steps. Round the final displayed answer to match the specification, document, or measuring tool you are using.