Image Dimensions Checker
Find the exact width and height of any image in pixels, with its aspect ratio, megapixels and file size. Check several images at once.
Runs in your browser. Your data is not uploaded.How our tools work
No image to hand? (CC0)
How do I check the dimensions of an image?
Select or drop one or more images and the checker shows each one’s exact width and height in pixels, read from the decoded image rather than the file name or a preview. You also get the aspect ratio, such as 16:9, the megapixels and the file size. Copy the dimensions with one click.
Not sure whether a form means pixels or KB when it says “image size”? Read our guide: Image Size vs Dimensions: What’s the Difference?
Formulas & Methods
Megapixels
Example: 4000 × 3000 = 12,000,000 pixels = 12 MP
Aspect ratio
Example: 1920 × 1080: both divide by 120, giving 16:9
Key features
Real pixel dimensions
The size comes from the decoded image, not from the file name or how large it looks on screen, so a 4000 × 3000 photo is reported as 4000 × 3000.
Aspect ratio and megapixels
Each size is simplified to a ratio such as 16:9 or 4:3. Unusual sizes also show the nearest common ratio.
Rotation noticed
When a phone photo is stored sideways and turned upright by its rotation setting, both the stored and the displayed size are explained.
Common uses
- Check that a photo meets an upload form’s pixel requirements
- Compare the resolution of several product photos
Supported formats and limits
- Input
- JPG, PNG, WebP, GIF, BMP and AVIF up to 40 MB each, plus HEIC where your browser supports it
- Batch
- Up to 20 images at a time
Reading the numbers: megapixels, file size and ratio
Pixels and bytes are separate things. A 12 MP photo can be a 1 MB JPG or a 10 MB JPG, depending on how much the camera compressed it, and the same pixels saved as PNG are far larger again. The checker shows both, so when a form limits the dimensions use the pixel figures, and when it limits the file size use the bytes; the Image Compressor changes the bytes, and the Image Resizer changes the pixels.
The ratio is simplified exactly, so 1920 × 1080 is 16:9 but 1920 × 1081 is 1920:1081. When the exact ratio isn’t a common one, the nearest common ratio within 1% is shown next to it, which tells you whether a photo will crop cleanly to a 4:3 print or a 16:9 slide.
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Frequently Asked Questions
Why is the size different from what I see on screen?
Screens and web pages usually scale images to fit. The checker reports the image’s own pixels, which is what upload forms and editors use.
Why are the width and height swapped for my phone photo?
Phones often store photos sideways and add a rotation setting. The checker shows the size the right way up, as apps display it, and notes the stored size.
Does the checker show DPI?
No. Pixel dimensions are what decide how detailed an image is. To see whether a file stores a DPI value, use the DPI / PPI Checker.
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Related guides & tutorials
Image Size vs Dimensions: What’s the Difference?
Image dimensions are pixels, image size is usually bytes, and they can move in opposite directions. What each means, what changes it and which one a form wants.
Image Metadata Explained: EXIF, Dimensions, Camera Data and Privacy
What image metadata is, how EXIF, XMP and IPTC differ, where each format stores them, why photos lose or change metadata, and what metadata can and can’t prove.
How to Check Image Metadata and What It Reveals
Check the metadata in a photo and read what it says: camera, settings, dates and GPS location, what each field means, and what to check before you share.