How to Print a Photo at an Exact Size From Your iPhone
How to print a photo at a specific physical size from iPhone — inches, cm or mm — and why Fit to Page can change the result.
Many people open Photos, tap Share, and print — only to discover the photo filled the whole sheet, shrank to a postage stamp, or came out a different size than they expected. Most iPhone printing paths think in presets and paper sizes. They rarely ask for an arbitrary physical width and height such as 4×6 in, 3×5 in, 2×3 in, 35×45 mm, or another custom size you need.
Pixels are not print size
A photo's pixel dimensions (for example 4032×3024) describe how much image data you have. They do not, by themselves, decide how large the print will be on paper. The same photo can print as a wallet-size crop or a full-page enlargement depending on the layout and printer settings.
Physical print size is measured with a ruler: inches, centimetres, or millimetres on the paper. If you need a photo that is exactly 100 mm wide, you need a workflow that places that photo in a frame of that width on a known page size — not just “make it bigger” or “fit to page.”
Inches, cm and mm
Pick the unit that matches the requirement you were given. Passport and visa forms often use millimetres. U.S. photo labs often use inches. Centimetres are common for crafts and school projects. Converting units after the fact is easy to get slightly wrong; setting the target unit up front is clearer.
Why Fit to Page changes the result
Printers and PDF viewers often include options such as Fit to Page, Scale to Fit, or similar automatic scaling. Those settings can enlarge or shrink the entire page so it fits the printable area — which changes the physical size of every photo on the sheet.
When exact dimensions matter, look for Actual Size or 100% and turn off automatic fitting. Also confirm the paper size in the print dialog matches the paper loaded in the printer and the page size used in the layout.
Printers still have limits
Even a correctly sized layout can vary slightly in real life. Printer hardware, drivers, minimum margins, borderless modes and paper path all affect what comes out. No iPhone app can override every printer's behaviour. For important jobs, print one test sheet and measure with a ruler before printing a full batch.
A practical exact-size workflow
- Decide the target width and height (and unit).
- Choose the paper size you will actually load (often A4 or US Letter).
- Place the photo in a frame at those physical dimensions.
- Crop or reposition if the frame aspect ratio differs from the photo.
- Preview the sheet.
- Print with Actual Size / 100%, or export a PDF and print that the same way.
- Measure the result and adjust printer settings if needed.
How PrintFit approaches this
PrintFit is built around physical dimensions rather than freeform collage resizing. Typical flow:
- Select a photo with Apple's photo picker
- Choose a preset size or enter custom inches / cm / mm
- Adjust Fit or Fill and reposition the crop if needed
- Let PrintFit lay the photo out on A4, Letter or another supported paper size
- Print with AirPrint or export a PDF
PrintFit creates the layout at the physical dimensions you specify. The printer or PDF viewer must still print without unwanted extra scaling. See why photos print at the wrong size if results are off, or how to create an exact-size photo PDF if you prefer to print later.