PhotoMathHow it works
Enter source width and height in pixels or load an image to read its dimensions. Select the physical print size and your target PPI. Fill crops the image to the print ratio, so some source pixels are discarded. Fit retains the whole image with margins; the required pixels refer to the actual image area inside the print. Effective PPI is limited by the lower-resolution axis. The largest size at target keeps the selected print composition. PPI describes pixel density, whereas a printer’s DPI describes output dots; they are not interchangeable controls.
Example
A 4000 × 3000 photo cropped to an 8 × 10 inch print retains 2400 × 3000 pixels. Effective resolution is 300 PPI and 60% of the original image area remains. Fitting the whole photo into the same print preserves all pixels but adds margins. A 1000 × 750 source gives 75 PPI with that crop. Changing the PPI target does not create detail, sharpen a blurry image or promise a particular lab result.
Assumptions and limitations
No. Image decoding, preview and export happen in your browser. Only numeric settings are saved locally. Reloading removes loaded photos; use the demo to try the image workflow.
Frequently asked questions
Are photos uploaded or saved?
No. Image decoding, preview and export happen in your browser. Only numeric settings are saved locally. Reloading removes loaded photos; use the demo to try the image workflow.
Does a 300 PPI result guarantee a sharp print?
No. Focus, source quality, viewing distance, paper and the printing process also matter. Choose a target appropriate to your intended output.
Are centimetres and inches interchangeable here?
Yes. Settings are stored in millimetres and converted for display. Changing units preserves the same physical sizes.