Digital Image Resolution Converter

Convert image resolution between DPI, PPI, pixels per centimetre, and pixel count for a specified physical print width.

Convert instantly

Enter a value and choose the units. Your answer updates as you type.

Value

Physical image width (inches)

Required when converting a pixel count to a density or back. The one-inch value is only a default.

From

Result

1 Pixels per inch (PPI)

Quick reference

Dots per inch (DPI)1 base units
Pixels per inch (PPI)1 base units
Pixels per centimetre (px/cm)2.54 base units
Pixel count across the physical width (px)1 base units

About the Digital Image Resolution Converter

DPI and PPI are often used interchangeably in casual workflows, but printer dots and image pixels are different things. This converter keeps the distinction visible and converts pixel count using the physical width you provide; it does not pretend that a bare pixel count has a density.

For example, 2,400 pixels printed across 10 inches is 240 PPI. A 300-PPI file at the same width needs 3,000 pixels. Use the Typography Converter for point and CSS-pixel sizing, or the Length Converter when the physical width is measured in millimetres.

Frequently asked questions

What does the digital image resolution measure?

DPI describes printer dots while PPI describes image pixels; they are nominal densities, not interchangeable physical dimensions. Pixel count can only become a density after a physical print width is specified, so the page uses a one-inch default that you can change.

What is a useful reference conversion for digital image resolution?

2,400 pixels across a 10-inch print is 240 PPI (and 240 DPI as a nominal output density).

Are the factors on this page exact?

SI prefixes and internationally defined units use their standard factors. Legacy and customary factors are retained at their published scientific definitions and may be rounded only for display.

Take this calculation further

Browse the converters calculators collection for more tools in this subject.

For a related calculation, use Frequency Wavelength Converter to convert electromagnetic frequency and vacuum wavelength using the exact speed of light, from hertz and gigahertz to metres and nanometres. Alternatively, use Illumination Converter to convert illumination and illuminance between lux, foot-candles, phot, and lumen-per-square-foot units.

For the underlying method, read Understanding Sound Decibels: Why the Scale Isn't Linear.