X (Twitter) Header Size Guide: 1500×500 and the Safe Zone

The X header is the widest piece of visual real estate on a profile, and it is also the one most often uploaded wrong. The number itself is simple — 1500 × 500 pixels — but the number is not the problem. The problem is that almost nobody sees the whole 1500 × 500.

The Official Dimensions

X asks for a header image at 1500 × 500 px, a 3:1 ratio. Accepted formats are JPG, PNG and GIF, and the practical upload ceiling for a header is around 2 MB. A static image is the safer choice: animated headers are not supported, so an uploaded GIF is flattened to its first frame.

You can upload something larger at the same 3:1 ratio — 3000 × 1000, for instance — and X will scale it down. That is often worth doing, because downscaling a sharp image produces a cleaner result than letting a 1500 px original get resampled on a high-density screen.

What Actually Gets Cropped

This is the part that catches people out. The header is displayed inside a container whose shape changes with the viewport:

• Desktop — close to the full 3:1 frame, though the exact width depends on the browser window.
• Mobile — noticeably shorter and wider in feel: the top and bottom are trimmed, so a design that fills the full 500 px of height loses its edges.
• Profile photo overlap — the circular avatar sits on the lower-left of the header and covers a meaningful bite out of that corner, roughly 200 px across on desktop and proportionally larger on a phone.

The working rule: treat the middle horizontal band as the only reliably visible area, and keep the lower-left corner empty. Anything important — a logo, a tagline, a face — belongs in the centre, slightly right of middle.

Why Headers Look Blurry

Three causes account for almost every blurry header.

The source was too small. Uploading a 750 × 250 image and letting X stretch it to 1500 × 500 doubles every flaw. Start at 1500 × 500 or above.

The file was recompressed. Exporting a JPG at quality 60, then letting X compress it again, stacks two rounds of lossy compression. Export at quality 85–90 and let the platform do the final pass.

The wrong format for the content. Photographs belong in JPG. Flat colour, text and logos belong in PNG, where JPG’s compression produces visible fringing around sharp edges.

Preparing the File

Getting from a source image to a correctly sized header takes two steps. First crop to the 3:1 ratio so you control what is kept, rather than letting the platform decide. Then resize to 1500 × 500 — or 3000 × 1000 if the original is large enough to support it.

If the resulting file is over the limit, compress rather than shrink the dimensions: a 1500 × 500 JPG at quality 85 will usually land well under 1 MB without any visible loss.

The Other Profile Images

While you are in there, two related sizes are worth getting right:

• Profile photo — 400 × 400 px, displayed as a circle. Design for the circle: anything in the corners of the square is cut off.
• In-stream images — 1600 × 900 px (16:9) is the safe default for a post image, which is displayed at a 16:9 crop in the timeline before it is opened.

A Short Checklist

• 1500 × 500 px, or a larger image at exactly 3:1
• Important content in the centre band, not the top or bottom edges
• Lower-left corner left clear for the profile photo
• JPG for photographs, PNG for text and flat colour
• Under 2 MB, exported at quality 85–90
• Checked on a phone, not only on a desktop browser

That last point is the one most worth keeping. The desktop preview flatters a header; the phone is where most people will actually see it.