Jernej LeticaPhotography Tools & Stories
Image Tools

Work out how large your photo can print

Convert pixels to print size, find the pixels for your paper and change a JPEG’s DPI tag locally.

Built and written by Jernej Letica

Local browser processing · No upload · No account required

Changing the tag keeps the compressed image unchanged. It does not add pixels.

How to calculate photo print dimensions

  1. Enter the image width and height in pixels, or choose a photo to read them.
  2. Choose a DPI value and centimetres or inches; the print dimensions update immediately.
  3. Edit either print dimension to calculate its corresponding pixel count, or choose a paper preset.
  4. For a JPEG, use the download button to change the resolution tag while keeping the compressed picture.

How I plan a print

I start with the pixels in the finished crop, then choose the paper. A DPI tag alone cannot tell me whether a print will look detailed. The viewing distance, paper and subject matter also affect how much resolution I need. I use the three print-size rows as planning points, then check the printer’s own requirements.

What I checked in the browser

My 6000 × 4000 pixel check at 300 DPI returned 50.80 × 33.87 cm. Selecting A4 at the same DPI returned 2480 × 3508 pixels. A JPEG saved with a new DPI tag decoded to exactly the same pixels in the browser check.

Pixels per inch and dots per inch

For photo dimensions, the number usually called DPI is pixels per inch, or PPI. A printer’s hardware dots are a different measurement. Here the calculation is pixels divided by pixels per inch. Multiplying the inch result by 2.54 gives centimetres.

Paper size does not decide the crop

Paper presets set the requested print rectangle. They do not crop a loaded photo or change its proportions. If the photo and paper have different shapes, decide whether to leave borders or crop first. The largest-print table retains the photograph’s original proportions.

What the JPEG tag changes

The download updates JFIF density and existing EXIF resolution fields when present. It leaves the compressed image scan intact and does not remove camera or location metadata. Applications may still ignore resolution tags and use their own page setup; verify the print size in the software that sends the job.

Tips for better results

  • Use the dimensions after cropping rather than the original camera resolution.
  • Switch to inches when matching a print lab’s specification in PPI.
  • The 150 DPI row is a larger print at lower pixel density, not extra image detail.

Privacy

Your file or entered content never leaves your device. The calculations and downloads happen locally in your browser.

Frequently asked questions

Does setting 300 DPI make a photo sharper?

No. The tag describes a default physical scale. It cannot create detail or increase the pixel count. A small photo with a 300 DPI tag remains a small photo, and enlarging it still spreads its pixels over more paper.

Why are A4 pixel dimensions rounded?

A4 measures 21 × 29.7 centimetres. Converting those lengths to inches and multiplying by 300 produces fractional pixels. The calculator rounds each side to the nearest whole pixel, giving 2480 × 3508.

Does the JPEG download re-encode my photo?

No. The tool changes density metadata around the compressed picture. The encoded scan stays intact. Existing camera and location information remains too, so this button should not be used as a metadata remover.

Can I use the 240 or 150 DPI size?

Those rows show the physical size at each pixel density. They help compare options, but they are not a print quality guarantee. Ask the print lab which density suits the paper, process and viewing distance.

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