Simple Aspect Ratio Calculator For 2026

What The Aspect Ratio Calculator Works Out

• Aspect ratio: width to height reduced to lowest terms by their greatest common divisor. 1920 x 1080 divides down to 16:9, the ratio shared by 4K (3840 x 2160), 1440p and most video platforms; awkward sizes are shown as a decimal such as 2.39:1 for cinema anamorphic.
• Scaled size: the height that keeps the ratio at your new width: new height equals new width times original height over original width, so 1920 x 1080 scaled to 1280 wide is exactly 720 tall. Resizing any other way stretches the picture.
• Total pixels: width times height in megapixels. Pixels scale with the square of the size, so serving a 4K image where a 1280-wide one is displayed wastes most of the bytes.
• Scale to new height (advanced): the reverse scaling sum, giving the width that keeps the ratio at a chosen height, for example when a video must be 720 or 1080 tall.
• Fit inside a box (advanced): the largest size that fits within a maximum width and height without cropping, using whichever side is the tighter limit. Useful for thumbnails and slot sizes such as 1200 x 630 link previews.
• Crop to a target ratio (advanced): the biggest centre crop of your image at a chosen shape (16:9, 9:16, 1:1, 4:5 and others), the percentage of the picture kept and the offsets for the crop box. Mismatched ratios always cost something: cropping loses picture, letterboxing adds bars, and stretching should never be the answer.
• Colour depth and uncompressed size (advanced): pixels times bytes per pixel gives the raw size in memory or as a BMP or TIFF; 24-bit RGB is 3 bytes a pixel, so a 1920 x 1080 frame is 6.2 MB. A JPEG is typically 5% to 15% of that and a PNG photo 30% to 60%.
• Round scaled sizes to (advanced): snaps scaled dimensions to even numbers or multiples of 8 or 16, which video encoders and JPEG compressors require or prefer. Odd heights cause errors in many H.264 and H.265 encoders.
• Common widths table (advanced): the height at your ratio for eight standard widths from 320 to 3840 pixels, with pixel counts and scale factors, which is the list you need when generating responsive image sets. The CSS aspect-ratio property holds the right shape while the file loads.