Choose the calculation method
Start with a physical size or the pixels in the source photo. Inches are the default for the US version.
DIMENSIONS
Convert physical size, pixels and DPI
Calculate the pixel dimensions needed for a physical print size, or see how a size in millimetres and inches relates to a chosen DPI.
Size calculator
Start with the physical size you need
Physical target
Choose millimetres for most laser and metric print workflows, or inches when that matches your source material or printer settings.
Calculated image requirements
This is a geometry calculation. It does not improve a small or blurry source image.
- Physical size
- —
- Inches
- —
- Pixels at chosen DPI
- —
- Image area
- —
How to use
Plan size, pixels and proportions
Set proportion and DPI
Lock proportions, use a starting ratio or rotate the format when needed. A DPI preset is only a guide for the next step.
Compare and use the calculation
Check the size at 150, 300 and 600 DPI, copy the calculation and open the next tool. The calculator never changes your file.
A useful distinction
Pixels describe an image; millimetres describe an object
- Pixels describe the number of points in a raster image.
- Millimetres and inches describe physical size for print, material and production.
- DPI links a planned physical size to a pixel requirement, but different applications can interpret metadata differently.
- Vector graphics scale differently from raster images because paths are described mathematically rather than by a fixed grid of pixels.
Questions and answers
Before you resize
Does a higher DPI make a photo sharper?
No. A higher target DPI can require more pixels for a given print size, but it cannot create original detail that is missing from the source.
Should I use millimetres or inches?
Use the unit that matches your production workflow and customer requirements. Millimetres are common for laser and CNC work; inches are common in some print and craft workflows.
Does this set my file metadata?
No. It is a planning calculator. Use an image or design editor to set the actual output dimensions and then inspect the exported file.
How do proportions and rotation work?
Enable the lock to update the other side when you edit a dimension. The 1:1, 4:5, 3:4, 16:9 and A4 buttons are starting ratios; Rotate format swaps width and height.
Does DPI apply to SVG?
Not in the same way as a photo. SVG is vector artwork and has no fixed pixel grid. Set its physical size and inspect the exported SVG separately.