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Aspect Ratio & Image Resolution Calculator

The word “resolution” is always mentioned when it comes to photos and digital imaging.

However, you may be wondering what it exactly is and how you calculate it. In this article, we’ll explain the basics of digital image resolution and how it affects your photo prints.

Understanding Image Resolution

Digital photos consist of individual pixels, and image resolution is a measure of how many pixels a digital image contains. Here are the three important things to know when talking about pixels and image resolutions.

Pixels Per Inch (PPI) & Dots Per Inch (DPI)

An image’s resolution or pixel density is measured in pixels per inch or PPI when displayed on a digital medium. In print, this measurement is known as dots per inch (DPI). 

The higher the PPI/DPI resolution, the more pixels each inch of the image houses, resulting in a sharper picture and a larger image size. 

Pixel density also influences how well your pictures can be seen. Denser pixels look better from up close. Conversely, if your pixels are less dense, the picture will look good from a greater distance but become, well, pixelated when viewed up close.

Pixel Dimensions

An image’s pixel dimension is the measure of the picture’s width and height in pixels. These dimensions are used to see how many pixels are in a digital image or scan. To calculate a picture’s pixel dimension, multiply the image height and width by its DPI. 

For example, a 4×6 photo scanned at 600 DPI would have dimensions of 2400×3600 pixels.

Aspect Ratio

The image aspect ratio is calculated by dividing image width by its height. Due to the range of screen shapes, aspect ratios are also used to determine which medium the photo is best displayed in.

How Image Resolutions Affect Your Printing Quality

An image’s pixel density and DPI become very important if you’re planning to print them out. Even if a photo looks fine on a screen, it might end up pixelated if the print resolution & DPI are too small. 

You can reduce the pixel density and DPI of a picture but not add it. So when taking a picture or scanning a photograph for print, it’s best to do so at the highest capture or scan resolution available. 

Even if you plan to display it on a mobile device, you’re futureproofing your picture in case you want to create a large print for framing. Setting a higher DPI for your scanned image files ensures good print quality, no matter your desired size.

However, you need to remember that higher resolutions & DPI have a larger image size. So you need to balance between more details in your print and a smaller output size in your image file.

Digital Image Calculators

Accurate image dimension calculations help make your image look great in any file format. Here are a set of simple calculator tools to measure your digital image and file size. Use the first calculator to find out your image’s dimensions, then use the second one to find its aspect ratio. We also provide an image file size calculator to estimate how much storage you need to accommodate the file.

Common Aspect Ratio Table

Use the table below to find out the five most common display mediums and their aspect ratio. For the best display, be sure to crop your images to fit them.

Aspect ratio

Common resolutions

Best used for


1080×1920, 480×800


4:3 & 16:9

1280×720, 1920×1080




Square images


1280×800, 1440×900

Widescreen displays and some smartphones


1350:1080, 960×768

Computer screens

Leave Printing To the Professionals

Choosing the right resolution & DPI is important to ensure your images are printed properly. However, it can be confusing to calculate it yourself. 

If you’re looking to get an old photo printed, Image Restoration Center is here to help. Our photo restoration and printing services can make sure that all your old photos can look their best when you put them in a frame.

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