Enter your dimensions
Set the original width and height, or choose a common aspect ratio.
Image Aspect Ratio Calculator for Matching Width and Height
Find an image’s ratio, calculate a matching width or height, and create a blank canvas in the resulting size.
Free to use. No signup or watermark.16:9
Calculate image aspect ratios and matching sizes.
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Reduced aspect ratio16:9
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The matching dimension updates automatically and rounds to a whole pixel.
Create a 3840 × 2160 imageResize an existing imageImage width and height calculations for common aspect ratios
Work out an image shape before you create or resize a design. Enter width and height to find the reduced aspect ratio, or choose a ratio and calculate the matching dimension for a new size. A visual preview helps compare landscape, square, and portrait shapes. Use the calculated dimensions to open an image canvas without an upload. For example, a 4:3 photo at 1200 pixels wide needs a 900-pixel height; use the image resizer after calculating if you want to process an existing file.
Ways to use the aspect ratio
Calculate the height needed for a 16:9 banner.
Compare portrait and landscape image proportions.
Create a new background with a matching aspect ratio.
How to calculate matching image width and height
An aspect ratio describes shape. It does not tell you how many pixels an image contains or how much detail a resized file will retain.
Reduce width and height to an image aspect ratio
For an image measuring 4032 × 3024 pixels, dividing both sides by 1008 gives 4:3. Enter the original width and height to see that reduced ratio. Rotating the image reverses it to 3:4, so check the orientation before calculating a target size.
Calculate one side from the other
At a target width of 1200 pixels, a 4:3 image needs a height of 900 pixels. The calculator rounds matching dimensions to whole pixels. Some ratios cannot be represented perfectly at every target width, so compare the rounded result with strict upload requirements.
Choose between calculation and processing
The calculator provides dimensions and can open a new blank canvas. It does not resample an existing photograph. Use the Image Resizer to change a real file, and decide there whether a different target ratio should crop the image, add padding, or stretch its contents.
Need help choosing a file? Read the image format guide or compare common pixel dimensions.
How to use the free aspect ratio tool
Calculate a matching size
Change the target width or height. The other dimension updates in whole pixels.
Create or resize an image
Open a plain canvas at the calculated size, or use the Image Resizer to change an existing picture.
Aspect Ratio: questions & answers
Everything you need before your next download.
Does the calculator resize an uploaded image?
No. It calculates dimensions and proportions. Use the result to create a new background or resize an existing image in your preferred editor.
Why might a calculated dimension need rounding?
Image dimensions use whole pixels. When a target size does not divide evenly into the chosen ratio, the matching dimension must be rounded to a usable pixel value.
Start your next creation with a simple image
Set the mood for a social post, refresh your wallpaper, or give a presentation a clean opening. Pick a canvas and make it yours.
Set the scene for your next post
Start with a 1080 × 1080 post or a 1080 × 1920 story. Pick colors that feel like you, download your background, then add photos and text in your usual editor.
Put your favorite colors on your screen
A soft sunset gradient or a quiet wash of color can make a screen feel like yours. Choose a 4K desktop canvas or a portrait phone size, then build a wallpaper around your own palette.
Give your next presentation a clean opening
Leave room for your ideas with a white canvas, or set the tone with a simple gradient. Start at 1920 × 1080, then add your title in a slide app or use the background for a project cover.