What this tool does
Choose an image or drop it on the page, and the tool shows its width and height in pixels, its aspect ratio, the megapixel count and the file size.
How it works
When you choose a file, your browser opens it through a temporary local address and the page reads the width and height, then works out the aspect ratio, megapixels and file size from those numbers. All of it happens on your device. The image is not uploaded and nothing is sent to this site.
Why these numbers matter
- Upload requirements. Many platforms ask for exact sizes, such as 1200 x 630 for share images, or minimums for logos and product photos.
- Performance. Pixel size and file size together show whether an image is heavier than it needs to be. A 6,000 pixel wide photo used in a 800 pixel column is a common cause of slow pages.
- Layout shifts. Setting
widthandheightattributes on<img>tags, matching the real ratio, lets the browser reserve space and avoids Cumulative Layout Shift. - Retina screens. A common rule is to provide an image at twice its display width for sharp results on high-density screens.
Limits
- It checks one image at a time.
- It reports the image’s real pixel dimensions, not any size applied by CSS on a web page.
- It doesn’t read or show EXIF details such as camera model or location.
- Formats that your browser can’t decode, such as AVIF in an older browser, can’t be measured.
To change the dimensions, use the Image Resizer, and to cut a specific shape use the Image Cropper.
Is my image uploaded to a server?
No. The size is read in your browser and the file never leaves your device.
Does it show EXIF data?
No. It reports dimensions, ratio, megapixels and file size.
Why can’t it open my AVIF or HEIC file?
Your browser has to be able to decode the format. Some browsers can’t read AVIF or HEIC.
What does 1:1 mean?
Width and height are equal, so the image is square.
Which file formats can it measure?
JPG, PNG, WebP and AVIF. Your browser must be able to decode the format to read its size.