Image Dimensions Checker

Most image problems start with a measurement you did not have. The upload form says “maximum 2000 px” and you do not know how wide the photo is. The print shop wants 300 DPI and you cannot tell whether your file is big enough. A banner looks wrong and the cause is a 4:3 image in a 16:9 slot. This page answers those questions in the time it takes to drop a file, without an editor, an install or an upload.

It reads only. Nothing is re-encoded and nothing is downloaded — the images you drop here are exactly as they were when you close the tab.

1. 1Drop one image or many. Every file you drop is added to the table. Drop a second batch later and the rows are appended rather than replacing what is there.
2. 2The file is decoded in the page. The browser decodes each image to learn its true pixel dimensions, and the first bytes are read to identify the real format.
3. 3The headline figures appear. Width, height, aspect ratio and file size sit across the top of the workspace for whichever image is selected.
4. 4The detail list fills in. Megapixels, the named ratio where there is one, orientation, format, whether the file has an alpha channel, and the print size at your chosen density.
5. 5Copy or compare. “Copy all details” puts every row on the clipboard as tab-separated text, ready to paste into a spreadsheet.

Dimensions

Width × height in pixels, taken from the decoded image. Photos with an EXIF rotation tag are reported the way they actually display.

Aspect ratio

The width-to-height relationship reduced to its simplest form, with the familiar name beside it when the image matches one — 16:9, 4:3, 3:2, 1:1 and so on.

Megapixels

Width × height ÷ one million. This is the figure cameras advertise and the one print labs ask about.

Orientation

Landscape, portrait or square, derived from the two dimensions.

Format

Identified from the file contents, not the extension. A mismatch between the two raises a notice.

Transparency

Read from the file header: whether the image declares an alpha channel. For formats where the header does not say, the row reports that it was not determined.

Print size at 72 / 150 / 300 DPI

The physical size the pixels would cover at that print density, in inches and centimetres. 300 is standard for photo printing, 150 for large posters viewed at a distance, 72 for screen mock-ups.

• No EXIF, camera settings or GPS. That is the metadata remover’s job, and it lists what it finds before removing it.
• No colour profile or bit-depth reporting. The browser normalises images to RGB as it decodes them, so those details are not reliably visible from here.
• Transparency is read from the header, which tells you an alpha channel exists — not whether any pixel actually uses it.
• Animated GIF and WebP report the dimensions of the image, not the frame count or duration.
• Extremely large images — well beyond 100 megapixels — may fail to decode at all. When that happens the file is reported as an error instead of a row.
• The list lives in the page only. Reloading clears it; nothing is remembered between visits.

A4 is 8.27 × 11.69 inches. At 300 DPI that needs roughly 2480 × 3508 pixels. Drop the photo, set the density to 300 DPI, and read the print width and height rows: if they reach or exceed those inch figures, the file is large enough. A 12-megapixel phone photo at 4032 × 3024 prints 13.44 × 10.08 inches at 300 DPI — comfortably more than A4 in landscape.

If it falls short, printing at 150 DPI doubles the physical size at some cost in sharpness. If it is far larger than needed, the resizer will bring it down to exact pixels, and the compressor will bring the file size down to a specific number of kilobytes.

• Faster than an editor

  No application to launch and no import dialogue. Drop the file and the numbers are on screen.

• Many images at once

  A table of every file you dropped makes odd sizes in a batch obvious at a glance.

• Print maths done for you

  Inches and centimetres at three common densities, rather than you dividing pixels by DPI on a calculator.

• Catches the wrong-format trap

  A PNG named .jpg is flagged, which explains a surprising number of rejected uploads.

• Copy straight to a spreadsheet

  Tab-separated output pastes into columns without any cleaning up.

• Read-only and local

  Nothing is modified, nothing is written, and the files never leave the device.

Each image is decoded in this tab to measure it. No upload request is made, nothing is written to local storage, a cache or a cookie, and no output file is produced at all. The list of measured images exists in the page’s memory and is gone when you reload or close it.

The page sets no cookies and loads no analytics. The host that served it can log the page request — IP address, timestamp, user agent — as every web host can; the Privacy Policy says so plainly and claims nothing beyond it.

PixelEditor is a small set of single-purpose image tools that run inside your web browser. Each one does a specific job — resize, crop, rotate, compress, convert, inspect, strip metadata — and each one has its own page so you can bookmark exactly the tool you keep needing.

The tools are built with the Canvas API and Web Workers. When you pick a file, the browser reads it from your own disk, works on it in memory, and hands you the result back as a download. There is no processing server involved, so there is no upload step, no queue, and no account.

Everything is free, there are no watermarks, and there is no paid tier that unlocks the real version. Read more about how PixelEditor works and why.