Resize an Image for Facebook Cover Photo
851 × 315 pixels — the exact size Facebook Cover Photo expects.
The dimensions
851 × 315 pixels, an aspect ratio of about 2.70:1. A 2.7:1 banner that is displayed differently on desktop and mobile, with the mobile crop taking the centre.
Crop, and what you will lose
The mobile crop keeps only the middle of the banner, so keep any text or logo inside the central band rather than toward the edges.
Two different crops from one file
On desktop the banner is shown at close to its full 851 × 315 proportions. On a phone it is narrower and roughly centred, so the left and right thirds disappear. A 400-pixel-wide band in the middle is visible in both cases — that is the only region you can rely on, and anything outside it should be expendable background rather than a logo or a line of text.
How to crop it here
Selecting cover scales your image uniformly until it fills the 851 × 315 rectangle, then trims the overflow from the centre. Contain would leave empty bands instead, which is wrong for an image meant to fill a frame, and stretch would distort faces.
Why this runs in your browser
The file is read from your disk by the browser, decoded with the browser's own codecs, and re-encoded in this tab. No upload request is made, nothing is queued on a server, and closing the tab leaves no copy anywhere. You can verify this in the network panel while it works.
How to use it
- Drop the image on the drop zone.
- Choose the Facebook Cover Photo preset, or type 851 and 315 directly.
- Set cover mode so the frame is filled without distortion.
- Check the crop keeps the subject centred, then download.
Worth knowing
- Target dimensions are 851 × 315 pixels, ratio 2.70:1.
- Used for page and profile cover.
- Cover fills the frame and crops the overflow; contain letterboxes instead.
- Aspect ratio is preserved in every mode except stretch.
Limitations
- Cropping is from the centre — frame the photo before uploading if the subject is off-centre.
- Upscaling beyond the original size adds no detail.
- Very small sources will look soft at 851 pixels wide.
- Platforms change their internal dimensions without notice; these are current published figures.