for x / twitter

Drop a cap on that X GIF.

X accepts gifs up to 15 mb (5 mb for ads). Over the cap, your post fails silently — no error, just nothing happens. Compress to fit.

gifcap producing an x-ready gif under the 15 mb post cap — 15 mb post · 3 mb ad · 1280×1080 max · windows desktop

x posts cap gifs at 15 mb · x ads cap them at 3 mb · 1280×1080 dimension cap · over the cap and the post silently fails

gifcap. drop your clip in gifcap. set the cap to 14 mb for posts or 2.5 mb for ads. resolution at 1280 px. gifcap binary-searches quality until it fits.

axis	manual ffmpeg / online tools	gifcap
hits x's 15 mb cap reliably	trial-and-error	always — binary search
3 mb ad cap support	requires separate workflow	set the cap, done
1280×1080 dimension cap	rejected by upload	preset for x width
quality at 3 mb	dithered ad copy	gifski per-frame palettes
cost	free	free tier; pro $29 lifetime

runs offline. no upload bar. same gifski engine as gifski.app. free tier covers 90% of use cases.

How gifcap solves this — in detail

X (formerly Twitter) silently rejects GIF uploads that miss any of three constraints: file size (15 MB organic / 5 MB ads), dimensions (1280×1080 max), or aspect ratio (1:1 to 3:1). The web upload widget rarely tells you which one tripped — it just refuses to attach the file. Diagnosing this without a deterministic encoder costs minutes per post.

gifcap targets all three deterministically. The binary-search size cap is set to 14 MB for organic posts (1 MB safety margin) or 2.5 MB for ads (sharp safety margin under the 3 MB ad performance cliff). The output dimensions clamp at 1280 px wide on the longer axis, and gifski's per-frame palette keeps the visual quality high in the tight ad cap.

Worth noting: X transcodes uploaded GIFs to MP4 server-side for autoplay in the feed. Your upload is a GIF; what your audience sees plays like a video. The encoder choice still matters because the transcode preserves what's there — it can't fix dithering or smudging in the source.

X (Twitter) — current GIF limits

Organic post cap: 15 MB
Ad post cap: 5 MB (3 MB is the practical performance ceiling)
Dimensions: 1280×1080 max
Aspect ratio: 1:1 to 3:1
Server-side transcode: GIF → MP4 for in-feed autoplay
Mobile autoplay: yes
Multiple GIFs per post: not supported (1 GIF max per tweet)
Failure mode: silent reject if any cap missed

download free see pricing — $29 lifetime 18 mb installer · signed · windows 10/11

FAQ

what's x / twitter's gif size limit?

15 mb per gif for organic posts, 5 mb for ad gifs. dimension cap is 1280×1080 with aspect ratio between 1:1 and 3:1.

why does my x gif post fail silently?

x's web upload doesn't always show clear errors. most common silent fails: file over 15 mb, dimension over 1280×1080, or aspect ratio outside 1:1–3:1. gifcap caps file size; x will accept anything that meets all three.

do x ads have a different gif limit?

yes — x ads cap gifs at 3 mb (5 mb is the absolute upload limit but performance falls off above 3). encode ads at the lower cap from the start.

are gifs really still effective on x?

yes — x converts uploaded gifs to mp4 server-side for autoplay in the feed. you upload a gif, the audience sees what plays like a video. quality at the cap matters more than ever.

last updated 2026-04-22 by alain · alain@gamutcreative.tv