Understanding DPI, PPI, and Print Resolution
When preparing images for physical printing or digital displays, resolution is measured in dots per inch (DPI) or pixels per inch (PPI). Higher DPI/PPI produces sharper detail and smoother gradients. Knowing the relationship between pixel dimensions and print size is essential for photographers, graphic designers, and anyone ordering prints.
Use this calculator in two modes: enter your image pixel dimensions to find the maximum print size at a given DPI, or enter a target print size to find how many pixels you need.
Common Print Resolution Standards
- 300 DPI: Professional photo printing, brochures, books, business cards, and fine art prints. Use this for anything viewed at hand-distance.
- 200–250 DPI: Magazines, packaging, and medium-format posters. Acceptable for casual photo prints.
- 150 DPI: Large-format posters and banners viewed from 1+ metre away. Canvas wraps and trade show graphics.
- 72–96 DPI: Standard screen display and web graphics. Not suitable for any physical printing.
Frequently Asked Questions
What is the difference between DPI and PPI?
DPI (Dots Per Inch) refers to printer ink dot density — how many physical ink dots a printer places per inch. PPI (Pixels Per Inch) refers to digital image or screen resolution. For print preparation, you work in PPI for your image file, and the printer's DPI determines how sharply those pixels are reproduced on paper.
What DPI is required for high quality photo printing?
300 DPI is the industry standard for sharp, high-quality physical prints, fine art, and photo books. Images below 150 DPI will appear noticeably blurry at normal viewing distances. For large-format prints viewed from more than 1 metre away, 100–150 DPI is acceptable.
How do I calculate pixel resolution from physical print size?
Multiply the desired print width and height in inches by the target DPI. For example, an 8×10 inch print at 300 DPI requires 2400 × 3000 pixels minimum. For a 20×24 inch poster at 150 DPI you need 3000 × 3600 pixels.
Can I upscale a low-resolution image for printing?
Software upscaling (Photoshop, Topaz Gigapixel AI) can improve low-resolution images, but it cannot recover detail that was never captured. A 72 DPI web image upscaled to 300 DPI for a 4×6 inch print will always be softer than a natively high-resolution photo. Use this calculator to know the true maximum print size before upscaling.
What resolution should I export for social media?
Social media platforms display images at 72–96 PPI. For Instagram, export at 1080 × 1080 px (square), 1080 × 1350 px (portrait), or 1080 × 608 px (landscape). For Twitter/X, use 1200 × 675 px for landscape. These are screen resolutions — DPI does not matter for digital display.
How many megapixels do I need to print A3 at 300 DPI?
An A3 sheet is 11.7 × 16.5 inches. At 300 DPI you need 3510 × 4950 pixels = approximately 17.4 megapixels. A modern 20+ megapixel camera can produce excellent A3 prints.