SOCIAL SIZE
☞ runs entirely in your browser — nothing is uploadedDrop your image here
or click to browse — JPG, PNG, WebP
Crop preview
OneImageTool
Free Image Tools
SOCIAL SIZE
851 × 315 on desktop — and a narrower window on a phone.
or click to browse — JPG, PNG, WebP
Crop preview
851 × 315
A cover photo is 851 × 315 on a desktop browser, an unusually wide strip at roughly 2.7:1. On a phone the same file is shown through a narrower, relatively taller window, so the left and right ends are cut away. One upload, two visible rectangles, and only the middle belongs to both.
That gives a simple rule for framing the crop: whatever has to be seen — a face, a product, a line of text — goes near the centre, and the ends carry background. It is the same discipline as a YouTube banner, for the same reason. Crop to the full 851 × 315 here so the desktop version is exact, but compose as though the outer thirds might not be there, because on most visits they will not be.
three steps
PNG, JPG or WebP. It is decoded in the page — nothing is uploaded, so nothing waits on a connection.
The crop box is already locked to the 851 × 315 shape. Drag it over the part that matters and resize it from any corner; the pixel size is shown as you go.
The export is exactly 851 × 315. JPEG is usually right; Facebook re-compresses uploads, so starting from a clean sharp file matters more than the format.
quick answers
851 × 315 pixels for the desktop layout, which is what this page exports. Phones show a narrower crop of the same image rather than a different file.
Uploads are re-compressed. You cannot avoid that, but you can avoid feeding it a soft or already-compressed image — export once at the exact size from a sharp original rather than re-saving a photo that has been through several rounds.
Yes, as long as the text sits in the middle. Text near the left or right end will be cropped off on mobile, and text near the bottom-left may sit under the profile picture on some layouts.
No. The crop and resize run in your browser; the file never leaves your device.