Print Size Calculator
Knowing the maximum print size your image can achieve at a given quality level is essential for photographers, designers, and print buyers. The relationship is simple: print size in inches equals pixel dimensions divided by DPI (dots per inch). A 6,000 x 4,000 pixel image printed at 300 DPI yields a 20 x 13.33 inch print. The same image at 200 DPI yields a 30 x 20 inch print, with slightly reduced sharpness. This calculator takes your image dimensions in pixels and a target DPI, then returns the maximum print width and height in both inches and centimetres, the megapixel count, a quality rating, and the closest standard paper size. A reverse calculator below answers the complementary question: how many pixels do you need to fill a specific print size at a given DPI? Enter your desired print dimensions and DPI and it returns the required pixel dimensions and megapixels. Whether you are ordering prints from a lab, preparing files for a book, or planning a large-format canvas print, this tool gives you the numbers you need before you commit to a print run.
Maximum print size: 20.00 x 13.33 inches (50.80 x 33.87 cm). Quality: Excellent (300+ DPI).
Maximum print size from pixels
Required pixels for a target print size
How many pixels do you need to fill a given print size at a given DPI?
Formula and calculation method
Pixels to print size
The relationship between pixels, DPI, and print size is straightforward:
- Print width (inches) = image width (pixels) / DPI
- Print height (inches) = image height (pixels) / DPI
- Print width (cm) = print width (inches) x 2.54
- Print height (cm) = print height (inches) x 2.54
- Megapixels = (image width x image height) / 1,000,000
Quality assessment thresholds
Quality ratings are based on widely used professional printing standards:
- Excellent: effective DPI of 300 or above. Standard for professional photo labs and fine-art inkjet printing.
- Good: effective DPI of 200 to 299. Acceptable for most commercial printing; most viewers cannot detect the difference from 300 DPI at normal viewing distances.
- Acceptable: effective DPI of 150 to 199. Suitable for large-format prints viewed from more than 60 cm, or where print size takes priority over sharpness.
- Low quality: effective DPI below 150. The image is likely to appear soft or pixellated at the chosen print size. Consider printing smaller or upscaling the image before printing.
Standard paper sizes
The calculator compares your computed print dimensions against common standard sizes to identify the closest match. Standard sizes used:
| Name | Width (in) | Height (in) | Width (cm) | Height (cm) |
|---|---|---|---|---|
| 4 x 6 | 4.00 | 6.00 | 10.16 | 15.24 |
| 5 x 7 | 5.00 | 7.00 | 12.70 | 17.78 |
| 8 x 10 | 8.00 | 10.00 | 20.32 | 25.40 |
| Letter (8.5 x 11) | 8.50 | 11.00 | 21.59 | 27.94 |
| A4 | 8.27 | 11.69 | 21.00 | 29.70 |
| 11 x 14 | 11.00 | 14.00 | 27.94 | 35.56 |
| A3 | 11.69 | 16.54 | 29.70 | 42.00 |
| 16 x 20 | 16.00 | 20.00 | 40.64 | 50.80 |
Quick reference: megapixels needed for common print sizes
| Print size | At 300 DPI (pixels) | At 300 DPI (MP) | At 200 DPI (pixels) | At 200 DPI (MP) |
|---|---|---|---|---|
| 4 x 6 in | 1,200 x 1,800 | 2.16 MP | 800 x 1,200 | 0.96 MP |
| 5 x 7 in | 1,500 x 2,100 | 3.15 MP | 1,000 x 1,400 | 1.40 MP |
| 8 x 10 in | 2,400 x 3,000 | 7.20 MP | 1,600 x 2,000 | 3.20 MP |
| A4 (8.27 x 11.69 in) | 2,481 x 3,507 | 8.70 MP | 1,654 x 2,338 | 3.87 MP |
| 11 x 14 in | 3,300 x 4,200 | 13.86 MP | 2,200 x 2,800 | 6.16 MP |
| A3 (11.69 x 16.54 in) | 3,507 x 4,962 | 17.40 MP | 2,338 x 3,308 | 7.73 MP |
| 16 x 20 in | 4,800 x 6,000 | 28.80 MP | 3,200 x 4,000 | 12.80 MP |
Print size calculator: frequently asked questions
What DPI do I need for a quality print?
For a print you will view at normal arm's length (around 30 cm or 12 inches), 300 DPI is the industry standard for sharp, photo-quality results. Most professional print labs require 300 DPI at the final print size. 200 DPI produces a good result that most people cannot distinguish from 300 DPI without close inspection. Below 150 DPI the print will appear noticeably soft or pixellated. For large-format prints viewed from a distance (posters, banners, wall art), 100 to 150 DPI is often sufficient because viewers stand further away.
What is the difference between DPI and PPI?
DPI (dots per inch) refers to the physical output of a printer: how many ink dots it lays down per inch. PPI (pixels per inch) refers to the density of pixels in a digital image or on a screen. When you set the resolution of an image file to 300 DPI in Photoshop, you are actually setting the PPI metadata that tells the printer how large to print the image. Printers then translate that into physical ink dots at their native DPI, which may be 600, 1200, or 2400 DPI depending on the device. The distinction matters mainly for understanding printer specifications versus image file specifications.
How many megapixels do I need for an A3 print?
An A3 sheet is 297 x 420 mm (11.69 x 16.54 inches). At 300 DPI you need 11.69 x 300 = 3,507 pixels wide and 16.54 x 300 = 4,962 pixels tall, giving about 17.4 megapixels. At 200 DPI you need approximately 7.7 megapixels. Most modern cameras with 20 megapixels or more can produce excellent A3 prints at 300 DPI. If your image is slightly short, printing at 240 DPI (Epson's optimum resolution for many inkjet printers) can give excellent results with fewer megapixels.
Can I enlarge a low-resolution photo for printing?
Yes, with limitations. Software upscaling (also called super-resolution or AI upscaling) can increase pixel dimensions without severe quality loss, but no software can recover detail that was never captured. Tools such as Adobe Lightroom, Topaz Gigapixel AI, and ON1 Resize use machine learning to add plausible detail when upscaling. As a general rule, enlarging to 150 percent of the original dimensions (2.25x the area) produces acceptable results. Beyond that, quality depends heavily on the subject: flat skies and uniform textures upscale better than fine detail like hair or foliage.
What DPI should I use for large-format printing?
Large-format prints (posters, banners, billboards, trade show graphics) are typically viewed from a distance, so lower DPI values are acceptable. A banner viewed from 1 to 2 metres away looks sharp at 100 to 150 DPI. A poster viewed from 30 to 60 cm should be 200 to 300 DPI. Billboards and vehicle wraps viewed from 5 metres or more can look excellent at 30 to 72 DPI. The general principle is that the further the viewing distance, the lower the DPI required for a perceptually sharp result.
Official sources
- Wikipedia: Dots per inch. Reference for DPI, PPI, and print resolution standards.
- Library of Congress: Still Image Formats and Standards. Authoritative guidance on digital image resolution and quality for archival and publication purposes.
Reviewed by the CalculatorHub team, edited by James Graham, 14 June 2026. See our methodology.