How to check image width and height
- Choose an image from your device, or drag it into the checker.
- Read Dimensions as width first, then height, in pixels (px).
- Check the aspect ratio and file size separately if a website or print service specifies both.
The checker reads the selected image's pixel dimensions, not the size of its preview on this page. It supports JPG, PNG, WebP, AVIF, and GIF files up to 40 MB, provided your browser can decode the format. It does not resize, compress, or upload your image.
What does 4000 × 3000 pixels mean?
An image measuring 4000 × 3000 px is 4000 pixels wide and 3000 pixels tall. Multiply width by height to get 12,000,000 pixels, or 12 megapixels. Its aspect ratio is 4:3, and its orientation is landscape because the width is greater than the height.
A 3000 × 4000 image has the same pixel count, but it is portrait with a 3:4 ratio. A square image has equal width and height. When checking an upload requirement, compare both dimensions in the requested order; the total megapixel count alone does not tell you whether the image fits.
Pixel dimensions, file size, and print size
An “image size” requirement can refer to different measurements. A photo can meet the required width and height while still exceeding a file size limit.
| Measurement | Units | What it describes |
|---|---|---|
| Pixel dimensions | px | The image's width and height, such as 4000 × 3000 px. |
| File size | KB or MB | Stored bytes, affected by compression, format, metadata, and image content. |
| Print size | in or cm | Physical output size at a chosen pixel density (PPI). |
Two 4000 × 3000 images can have different file sizes. Compressing a file can reduce its bytes without changing its dimensions; resizing changes the pixel grid. Changing a DPI metadata value alone does not add pixels or make the image more detailed.
For physical dimensions, use the pixels to print size calculator. At 300 PPI, 4000 × 3000 px produces approximately 13.33 × 10 inches. For a required photo or paper size, consult the print size pixel chart.
Check the aspect ratio before resizing or cropping
Aspect ratio is the relationship between width and height. A 4000 × 3000 photo reduces to 4:3. Resizing to 2000 × 1500 preserves that ratio; fitting the same photo into a square requires cropping, borders, or distortion. An exact size match requires the correct pixel dimensions as well as the correct ratio.
| Ratio | Width × height (px) | Typical use |
|---|---|---|
| 1:1 | 1080 × 1080 | Square graphics |
| 4:3 | 4000 × 3000 | Cameras and screens |
| 3:2 | 6000 × 4000 | Photography |
| 4:5 | 2400 × 3000 | Portrait 8 × 10 prints |
| 16:9 | 1920 × 1080 | Widescreen video |
Frequently asked questions
Why does a website show a different image width or height?
A website can display an image at a smaller size using its layout rules. A 4000 px wide file displayed in a 400 px wide space still contains its original pixels. A website may also serve a resized copy. This checker measures the file you select; it does not scan images at a website URL or measure their on-screen layout.
Can I check image dimensions without an online tool?
On Windows, right-click a saved image, open Properties, and look for Dimensions under Details. On macOS, select the image in Finder, choose Get Info, and look under More Info. Available details depend on the file format and operating system. Compare pixel dimensions, not the file size in KB or MB.
Can I check a photo from my phone?
Yes. Choose image opens your device's file or photo picker. Use a supported JPG, PNG, WebP, AVIF, or GIF file. HEIC and HEIF are not supported inputs; export a supported copy first. If an export or messaging app resizes the photo, the results describe that copy.
Does checking an image change it?
No. ToolFoundry reads the selected file and creates a temporary local preview. It does not modify or upload the original, and no account is required.
Why is the aspect ratio not a familiar number?
Cropped images can have uncommon proportions. The checker reports the exact reduced integer ratio instead of rounding to the nearest preset. For example, 1001 × 1000 px is 1001:1000, not exactly square.