How can I make a blurry or low-resolution image sharper for free?
If the photo is on an Android phone, try Google Photos' own Unblur first (the improved version needs at least 4 GB of RAM, and some tools are Pixel-only). On a computer, Upscayl is a free, open-source AI upscaler for Windows, macOS and Linux that runs on your own machine, so the photo is not uploaded. Online, Let's Enhance gives 10 free credits when you sign up, with a watermark on free results, and paid plans from $9 a month billed annually ($12 monthly); Topaz's web plan for images is $19 a month. Know what this does: AI upscaling invents plausible detail, so it can make a face or a product shot look crisp, but it cannot bring back text or a number plate that was never legible, and the result should never be passed off as the original in a dispute or as evidence. Rule: the phone tool for a snapshot, Upscayl for anything private or in bulk.
Google's guide to Magic Eraser, Unblur, portrait blur and suggested enhancements, with the device requirements (at least 3 GB RAM; 4 GB for improved Unblur; some tools Pixel-only).