Direct answer. In PrintExactly, set the photo to its physical dimensions, match the loaded paper, turn off Scale to Fit in the macOS print dialog, set Scale to 100%, and print.
The 3-step method
- Set the photo's physical dimensions. In PrintExactly, enter the width and height in mm, cm, or inches. The value you type is the actual physical size, not a fit-to-paper guess.
- Match the document paper to the loaded paper. If the document is sized for A4 but the tray has US Letter, macOS silently scales. Match them first.
- Print at 100% with Scale to Fit off. Turn off Scale to Fit, set Scale to 100%, confirm the printable area shows the photo fully inside, and send the job.
Why a photo doesn't print at actual size on Mac
- Scale to Fit is on. This is the most common reason a Mac print does not come out at actual size. The dialog defaults to it when the document paper does not match the loaded paper.
- Borderless expansion. Borderless modes shift actual size by 1–2% so the image fills the paper edge. Use a bordered paper size for true actual-size output.
Frequently asked questions
Why does my photo print at a different size than the size I typed?
macOS Scale to Fit may be on, the loaded paper may not match the document, the printer driver may apply its own scale, or borderless expansion may shift the image. PrintExactly shows paper and printable-area checks; driver-specific controls still need a manual review.
Is actual size the same as 100% scale?
100% page scale is required for actual-size output, but it is not the whole guarantee. The document paper, printer driver, borderless mode, and hardware tolerance can still affect the measured result.