Free Online Image Size Checker – Check Dimensions in Pixels

How to Check the Size of an Image

The quickest way to check the size of an image is to add it to the checker above. The result shows the width and height in pixels, the total pixel count, the file size in KB and MB, the exact byte count, the format, the aspect ratio, and the orientation. You can add more than one file and compare the results side by side.

You do not need to install an app or create an account. The image is read in your browser, so the file stays on your device. That matters when the photo contains a passport, a child, a product prototype, or anything else you would rather not send to a stranger's server.

Check image size on Windows

In File Explorer, select the image and open the Details pane. You can also right-click the file, choose Properties, and open the Details tab. Windows shows the dimensions and the file size there. If the Details tab is empty, the file may be a format Windows cannot read, such as HEIC without the optional codec.

Check image size on Mac

Select the file in Finder and press Command+I. The Info window shows the dimensions under More Info. For a closer look, open the image in Preview and choose Tools > Show Inspector. The inspector shows the pixel dimensions, the resolution tag, and the file size. The resolution tag is metadata; it does not change the number of pixels.

Check image size on iPhone

Open the photo in the Photos app and tap the info button, or swipe up on the photo. iOS shows the camera, lens, and file details. For an exact width and height, open this page in Safari, tap the upload button, and choose the photo. If the photo is HEIC and Safari can read it, the checker shows the dimensions. If it cannot, convert the photo to JPG first.

Check image size on Android

In Google Photos, open the image, tap the three-dot menu, and choose Details. Files by Google also shows the size and dimensions for many formats. For a pass or fail check against a platform limit, use the checker on this page in Chrome. It can read JPG, PNG, WebP, GIF, AVIF, SVG, and BMP files without uploading them.

How to Check Image Dimensions in Pixels

Image dimensions are written as width × height. A 1920 × 1080 image is 1,920 pixels wide and 1,080 pixels tall. Multiply the two numbers to get the total pixel count: 2,073,600 pixels, or about 2.07 megapixels. Camera makers and phone makers usually quote the megapixel figure, while websites and print labs usually ask for the width and height.

Open any result card above to see the width, height, total pixels, megapixels, aspect ratio, and orientation. The orientation is simply landscape when the width is larger, portrait when the height is larger, and square when both numbers match. The aspect ratio is the reduced relationship between the sides. A 1920 × 1080 image is 16:9. A 1200 × 630 image is about 1.91:1.

Dimensions are not the same as display size. A 4000-pixel-wide photo can appear in a 200-pixel-wide card on a web page. The browser scales it down, but the file still carries all 4000 pixels. That is why a large photo can slow a page even when it looks small on screen. The reverse is also true: a small image stretched across a hero section will look soft because the browser has to invent pixels.

How to Check Image File Size in KB and MB

File size is the amount of storage the image uses. This page shows it in KB, in MB, and as an exact byte count. It uses 1 KB = 1,024 bytes and 1 MB = 1,024 KB, which is the convention most file managers use. Some storage products use decimal units, where 1 MB = 1,000,000 bytes. That is why the same file can look slightly different in two places.

File size matters for email attachments, contact forms, marketplace listings, job portals, and page speed. A limit written as “2 MB” is often enforced by the upload form before your file ever reaches the server. If the form rejects the file, check both the pixel dimensions and the file size. Cropping a photo reduces pixels; exporting it at a lower quality reduces bytes. Those are different operations.

A photograph with fine detail usually has a larger file than a flat graphic at the same dimensions. A PNG with transparency can be much larger than a JPG of the same scene. A GIF may be small because it is limited to 256 colours, not because it is high quality. The exact byte count in the result card lets you compare two exports without guessing from the rounded MB figure.

Image Size vs Image Resolution

People use “image size” and “image resolution” for three different things. Pixel dimensions describe how many pixels are in the file. PPI describes how densely those pixels are placed on paper when you print. File size describes how many bytes the file takes up. They are related, but none of them is a direct substitute for another.

PPI means pixels per inch. DPI means dots per inch, which is a printer specification. The two terms are often used interchangeably in photo editing, even though they are not the same. A 3000 × 2000 image has enough pixels for a 10 × 6.67 inch print at 300 PPI. The same file can make a 20 × 13.33 inch print at 150 PPI. The pixels did not change; only the density changed.

The old advice that web images should be 72 DPI and print images should be 300 DPI is incomplete. A browser lays out an image using its pixel dimensions and CSS, not a 72 DPI tag. The DPI value stored in the file is metadata. Changing it does not add pixels, remove compression, or make a soft photo sharp. For print, the useful question is: how many pixels do I have, and how large will the print be?

File size is also separate from sharpness. A heavily compressed JPG can be small and still look good on a phone, while an uncompressed TIFF can be huge and contain the same detail. A low-quality image scaled up to a large canvas can have a massive file size and still look blurry. Use the checker to see all three numbers together before you decide what to fix.

What Size Should My Image Be?

Start with the place where the image will appear. A profile picture, a link preview, a print, and a full-screen hero image have different jobs. The table below gives a practical starting point for common uses. Platform limits change, so check the current help page before a campaign or a paid upload.

The quick-fill buttons in the checker load these values into the width, height, and file-size fields. They are starting points, not guarantees. A platform can crop, recompress, or reject a file after you upload it. Keep a copy of the original and check the result after the platform processes it.

How Big Can I Print My Photo?

Divide the pixel width by the target PPI to get the print width in inches. Divide the pixel height by the same PPI to get the print height. A 3000 × 2000 photo can print at 10 × 6.67 inches at 300 PPI, or 20 × 13.33 inches at 150 PPI. If you want a 4 × 6 inch print at 300 PPI, you need 1200 × 1800 pixels, because 4 × 300 = 1200 and 6 × 300 = 1800.

Use 300 PPI when the print will be held in the hand or viewed closely: a photo book, a business card, a small product label. Use 150 PPI for a poster or a large wall print that will be viewed from a few feet away. A billboard can use even fewer pixels per inch because the viewing distance is large. The right number depends on the viewing distance, not on a single rule for every print.

The print panel above does this math for the selected image. It lists the size in inches, centimetres, or millimetres, then checks the image against common paper sizes. A “good” result means the file has at least 300 PPI for that paper. “Acceptable” means 150–299 PPI. “Too small” means less than 150 PPI. The labels are a guide; your print lab may have its own requirements.

Frequently Asked Questions