Understanding your result
Width and height describe a print using every entered pixel without cropping. The comparison table shows how the same image size changes at other PPI values; it does not assess sharpness from the image itself.
If the print frame uses a different shape, the Image Aspect Ratio Calculator compares the crop and border dimensions.
The formula
Pixels per inch describe how densely the image pixels are placed on paper. Doubling PPI halves each physical dimension. The megapixel result is width times height divided by one million, which is a pixel count rather than a file-size estimate.
Worked example
An image measuring 6,000 by 4,000 pixels prints at 20 by 13.333 inches at 300 PPI. That is approximately 50.8 by 33.867 cm. At 150 PPI, the same unchanged pixels occupy 40 by 26.667 inches.
How to use this calculator
- Read the image’s pixel dimensions from its properties or editor.
- Enter the PPI requested by your print provider.
- Compare the calculated dimensions with your intended print and frame.
PPI and printer DPI
PPI describes the image data per physical inch. Printer DPI describes a device’s ink or toner dot resolution and is not interchangeable with image PPI. A printer can use multiple dots to reproduce a single image pixel. Use the image-resolution requirement supplied for your particular print job.
Changing size without adding detail
Editing a resolution number while keeping resampling off changes print dimensions but preserves the original pixels. Upsampling can create additional pixels without recovering missing detail. Image focus, compression artifacts, paper, and viewing distance also affect the result, so this arithmetic cannot promise print quality. If the paper has a different aspect ratio, decide whether to crop the image or leave borders before choosing final dimensions.
Assumptions & limitations
What this calculation assumes
- The image uses square pixels and no crop is applied.
What to keep in mind
- Does not inspect a file, resample pixels, or evaluate visual sharpness.
Common questions
Is 300 PPI always necessary?
No single value suits every output. Print process, viewing distance, and the provider’s requirements determine an appropriate target.
Will changing PPI make the file smaller?
Not by itself when the pixel dimensions remain fixed. File size also depends on format, compression, bit depth, and image content.