Resolution Calculator

Screen resolution is the number of distinct pixels that can be displayed on a screen, expressed as width × height. For example, 1920 × 1080 means 1,920 pixels across and 1,080 pixels down, totaling about 2.07 million pixels.

PPI (pixels per inch) measures pixel density on a screen — how many pixels fit in one inch of display. DPI (dots per inch) measures print resolution — how many ink dots a printer places in one inch. A 300 DPI print setting means the printer outputs 300 dots per inch of paper.

Standard 4K UHD resolution is 3840 × 2160 pixels, which equals 8,294,400 total pixels (about 8.3 megapixels). The cinema standard 4K DCI is slightly wider at 4096 × 2160. Both are commonly referred to as "4K."

Use the formula: PPI = √(width² + height²) / diagonal size in inches. For a 27-inch 2560 × 1440 monitor: √(2560² + 1440²) / 27 ≈ 108.8 PPI. This tool does this calculation instantly — just enter your resolution and screen diagonal.

Use 300 DPI for high-quality photo prints — this is the industry standard for photographic reproduction. 150 DPI is acceptable for large-format prints viewed from a distance (posters, banners). 600 DPI or higher is used for fine art prints or detailed reproductions where viewers may examine the print up close.

Scaling up (upsampling) will always lose some quality because the software must invent new pixel data. Scaling down (downsampling) preserves quality well. This tool shows the new pixel dimensions when you scale by a percentage, but the visual quality depends on the content and the resampling algorithm your image editor uses.

1920 × 1080 simplifies to a 16:9 aspect ratio. This is the most common widescreen ratio used by HDTVs, monitors, YouTube videos, and most streaming content. This tool simplifies any resolution to its lowest whole-number ratio automatically.

Divide each pixel dimension by 300 to get the print size in inches. A 6000 × 4000 pixel photo (24 MP) prints at 20″ × 13.33″ at 300 DPI. Use the Print Size section of this calculator to check instantly with any resolution and DPI combination.

One megapixel equals one million pixels. A 4000 × 3000 image has 12,000,000 pixels, or 12 megapixels (MP). Megapixel count is a rough indicator of image detail — more megapixels allow larger prints and more cropping flexibility, but sensor quality and lens sharpness matter just as much.

At 150 DPI (standard for large posters viewed from several feet away): 24 × 150 = 3,600 pixels wide, 36 × 150 = 5,400 pixels tall — so you need at least a 3600 × 5400 (19.4 MP) image. At 300 DPI for close-up viewing you'd need 7200 × 10,800 (77.8 MP), which exceeds most cameras.