Aspect Ratio Calculator. Keep every image perfectly in proportion. Calculate matching width and height values so your image keeps its proportions. Includes 1:1, 4:5, 9:16 and 16:9 presets for social media, print and web. Every conversion runs entirely inside your browser using the Canvas API and (where needed) heic2any, so your photos never touch our servers and stay completely private. Batch-convert hundreds of files at once, fine-tune output quality, resize on the fly and download the results as a single ZIP. There is no signup, no watermark and no daily limit — just a fast, free tool that works on Windows, macOS, Linux, iOS and Android. Whether you need to attach images to email, prepare product photos for Etsy, eBay or Amazon, fix HEIC files exported from an iPhone, shrink screenshots before uploading or convert WEBP to a more compatible format, the right workflow is one click away. Common topics covered here include aspect ratio calculator, image ratio calculator, resize without stretching, 16:9 calculator, photo proportions.