Free Resolution Calculator – Megapixels & Screen PPI

Multiply width × height in pixels, then divide by one million. A 6000×4000 pixel image (common for modern DSLRs) gives 24,000,000 ÷ 1,000,000 = 24 megapixels. This is the total sensor resolution.

Resolution (megapixels) is the total pixel count — how much detail the image contains. PPI (pixels per inch) is the density at which those pixels are displayed. A 24MP image at 72 PPI on a monitor looks the same as 24MP at 300 PPI on paper — the print is just physically smaller.

Billboards are viewed from distance and printed at low DPI, often 15–30. A 10MP camera is sufficient for most billboard work. Conversely, a small magazine ad viewed up-close needs 300 DPI and benefits from 20MP+ resolution.

Not always. Screens with very high PPI (300+, like modern phones) look crisp, but the difference between 400 PPI and 500 PPI is invisible to the human eye at normal viewing distance. For print, 300 DPI is the practical ceiling for most applications.

4K UHD is 3840×2160 pixels (8.3 megapixels). True 4K cinema (DCI 4K) is 4096×2160 (8.8 MP). 4K has four times the pixels of 1080p Full HD (1920×1080, ~2.1 MP).

Uploading higher resolution than a platform needs wastes bandwidth without visible benefit. Instagram scales everything to 1080px on its widest side. YouTube compresses to 1080p. LinkedIn limits file sizes. Check each platform's recommended dimensions rather than uploading full camera resolution.

1920×1080 (Full HD) is the baseline. For 1440p monitors, aim for 2560×1440. For 4K displays, 3840×2160 ensures the image isn't upscaled. Most stock photography sites offer wallpapers at 3840×2160 or higher.