How to use the Resolution Calculator
Enter the pixel size
Width and height start at 4000 and 3000.
Type any field
Change the width, the height, the scale percent, or the DPI. Megapixels, the scaled size and the print size update as you type.
Read the three numbers
The big number is megapixels. Under it are the scaled size, the print size in inches, and same-ratio sizes.
Summarize with
Megapixels and scale
MP = W×H/1,000,000. 4000×3000 = 12 MP. A 50% scale is 2000×1500. Those two fixtures are generated here, not typed by hand.
Same-ratio suggestions come from resolutions.json. Clicking a size fills width and height on this page. The address bar stays on the Resolution Calculator.
Print size from resolution
Inches = pixels ÷ DPI. A 4000-pixel side at 300 DPI is 13.33 in. Use the dedicated dpi to pixel page if you start from paper size instead of pixels.
Common mistakes
Mixing megapixels with megabytes. MP is pixel count, not file size.
Scaling only one side and breaking the ratio.
How this resolution calculator stays separate
The homepage owns “aspect ratio calculator.” This URL owns megapixels, percent scale and a print-size invert. Same engine, different keyword and a different first question: how many pixels, not which colon pair.
4000×3000 = 12 MP is a fixture. If the live tool ever disagrees, the build should have stopped. Suggested sizes come from resolutions.json, each with a last_verified date.
Use the resolution calculator when a brief names a pixel count and you need the matching smaller size or the print inches. Scale both sides by the same percent so the shape stays put. Open the converter only when the destination asked for a different shape.
Matching a named size
After you have megapixels, pick a same-ratio size from resolutions.json rather than inventing a near miss. 1920×1080 and 1280×720 share 16:9; 1920×1200 does not. Clicking a size fills width and height here. Nothing is added to the page address.
Percent scale is a multiply, not a ratio change. 50% of 4000×3000 is 2000×1500, still 4:3, still 3 MP. Use convert if the destination asked for 16:9 instead of a smaller 4:3.
Frequently asked questions
What is a resolution calculator?
A tool that reports megapixels, scaled sizes and optional print inches from pixel width and height.
How many megapixels is 4000×3000?
12 MP.
What is 50% of 4000×3000?
2000×1500.
Does resolution change aspect ratio?
Not if both sides scale by the same factor.
Where is PPI?
On the PPI calculator, which starts from a diagonal.