Aspect Ratio Calculator
Free aspect ratio calculator for images, video, and print. Calculate dimensions, simplify ratios, and find the perfect size for any screen or format.
Free aspect ratio calculator for images, video, and print. Calculate dimensions, simplify ratios, and find the perfect size for any screen or format.
YouTube, TV, gaming monitors, presentations
iPad, classic TV, security cameras
DSLR cameras, 35mm film, 4x6 prints
Instagram portraits, Pinterest, mobile ads
TikTok, Instagram Reels, YouTube Shorts
Posters, menus, marketing materials
Documents, resumes, flyers
Use 16:9 for YouTube, Netflix, and most video platforms. Use 9:16 for TikTok and Instagram Stories.
Use 4:5 for Instagram feed posts (maximum visibility). Use 1:1 for profile pictures and thumbnails.
Use 3:2 for DSLR/mirrorless cameras and 4x6 prints. Use 4:3 for smartphones and tablets.
Use 8.5x11 for documents and letters. Use 11x17 for posters and tabloid-size prints.
Select whether you want to calculate height from width, width from height, or simplify an existing ratio to its smallest form.
Input your known dimension and the desired aspect ratio. Choose your preferred unit: pixels, inches, centimeters, or millimeters.
See the calculated dimensions instantly along with a visual preview. Copy the result to your clipboard with one click.
An aspect ratio describes the proportional relationship between an image's width and height. It's expressed as two numbers separated by a colon (e.g., 16:9). The first number represents width, the second represents height. An aspect ratio of 16:9 means for every 16 units of width, there are 9 units of height.
To find the aspect ratio from pixel dimensions: 1) Find the Greatest Common Divisor (GCD) of width and height, 2) Divide both dimensions by the GCD. For example, 1920x1080: GCD is 120, so 1920÷120=16 and 1080÷120=9, giving you 16:9.
It depends on the platform: Instagram posts work best at 4:5 (portrait) or 1:1 (square). TikTok and Stories need 9:16 (vertical). YouTube and Facebook videos use 16:9 (landscape). LinkedIn prefers 1.91:1 for link previews.
Aspect ratio itself doesn't affect quality—it only determines proportions. However, if you crop an image to a different aspect ratio, you're removing pixels, which effectively reduces resolution in that dimension. Always start with the highest resolution source possible.
Resolution is the total number of pixels (e.g., 1920x1080 = 2,073,600 pixels or about 2MP). Aspect ratio is the shape/proportion (1920:1080 simplifies to 16:9). Two images can have the same aspect ratio but different resolutions (e.g., 1280x720 and 1920x1080 are both 16:9).
To maintain aspect ratio when resizing: 1) Change only one dimension (width OR height) and calculate the other proportionally, or 2) Lock/constrain proportions in your image editor (usually a chain-link icon), or 3) Use our calculator to find dimensions that maintain your desired ratio.