Image Dimension Checker — Size, Ratio & Megapixels

← Darkroom IsleThe Creative Island · Island 12

Drop in any image — see width, height, exact ratio, megapixels and file size at once.

Choose an image

How to use this tool

1. Choose any image from your device.
2. Read the full report: dimensions, simplified ratio, megapixels, format, file size and max print size.
3. The image preview confirms you're inspecting the right file.

Example

A photo reports 4032 × 3024, ratio 4:3, 12.2 MP — the classic smartphone shot. At 300 DPI it prints up to 34 × 26 cm (13×10 inch), and as a full-width web image it is three times wider than needed: resize to 1200px and save the bandwidth.

The formula

ratio = W:W÷gcd(W,H) · megapixels = W × H ÷ 1,000,000 · print cm = pixels ÷ 300 DPI × 2.54

What the result means

The dimension report answers the three questions every image task asks: is it the right shape (ratio), is it big enough for the job (pixels → print size at 300 DPI), and is it heavier than it needs to be (KB per pixel). A 12 MP photo on a webpage is a delivery truck carrying one letter.

Frequently asked questions

What do I check before uploading a form photo?

Two numbers from this report: the pixel dimensions (some forms demand minimums like 132×170) and the KB size (many cap at 20–100KB — the compressor bench handles that).

What counts as 'high resolution'?

For screens, anything at or above the display size is perfect. For print, use the DPI line: 300 DPI is professional print; 150 DPI is usually acceptable for large posters viewed from distance.

Why does my 12MP photo look worse than a 6MP one?

Megapixels measure quantity, not quality — lens, sensor and compression decide quality. Two very different questions.

Is my image uploaded?

No — it's opened locally by your browser; the report is generated on your device.

More tools from Darkroom Isle

Image CompressorShrink to any KBImage ResizerExact pixels or percentagesPrint Size CalculatorPixels to print sizeAspect Ratio CalculatorOn Palette Atoll

Explore the island world

• Darkroom Isle — the island where this tool lives.
• The Main Island — drive the boat, explore the whole world.
• The 90s Kids Island — where most of us started.

Privacy & data: this tool runs entirely in your browser — nothing you type is uploaded, saved or sent anywhere. · Disclaimer: your images are opened and processed by your own browser only — files never leave your device, and originals are never modified. · Privacy Policy · Disclaimer