Every platform thinks its specs are the universal standard and most editors learn the differences the hard way — by uploading a 16:9 master to TikTok and watching the centerpiece of the shot get cropped off. This is the cheat sheet to keep open the next time you ship. Specs as of April 2026; platforms tweak limits quarterly so always sanity-check the in-app uploader before a hero campaign.
The five things that change per platform
Each platform's spec is the same five-axis problem with different answers. Aspect ratio dictates the shape of the canvas. Resolution sets the pixel count. Length cap controls how long the cut can run. Codec / bitrate / file size set the upload constraints. Audio LUFS and caption requirements determine how the playback feels. Get all five right and the platform's encoder leaves your file mostly alone; get any wrong and the platform re-encodes, often badly.
YouTube — long-form
- Aspect ratio: 16:9.
- Resolution: 1920×1080 (1080p) for SDR, 3840×2160 (4K) for premium delivery.
- Length: up to 12 hours; verified accounts get longer caps. Practically, sweet spots are 8–14 minutes for educational and 18–25 minutes for essay/long-form.
- File size: up to 256 GB or 12 hours, whichever is smaller.
- Codec: H.264 High Profile, MP4 container. AV1 accepted and re-encoded.
- Bitrate: 8 Mbps for 1080p SDR, 12 Mbps for 1080p60, 35–45 Mbps for 4K SDR, 53–68 Mbps for 4K60.
- Audio: stereo or 5.1, AAC-LC at 384 kbps, target -14 LUFS integrated.
- Captions: auto-captions are passable; upload your own .srt or .vtt for accuracy.
YouTube Shorts
- Aspect ratio: 9:16 (vertical).
- Resolution: 1080×1920.
- Length: up to 60 seconds. Sweet spot 15–35 seconds for retention.
- Codec: H.264, MP4. Bitrate ~12 Mbps for 1080p vertical.
- Audio: -14 LUFS integrated, peaks under -1 dBTP.
- Captions: hardcoded burned-in captions perform measurably better than YouTube auto-captions for Shorts.
TikTok
- Aspect ratio: 9:16. 1:1 and 16:9 supported but pillarboxed/letterboxed in the feed.
- Resolution: 1080×1920.
- Length: up to 60 minutes for verified accounts; 10 minutes is the practical norm. Sweet spot for organic reach: 21–34 seconds.
- File size: up to 287.6 MB on iOS, 72 MB on Android upload.
- Codec: H.264, MP4 or MOV. H.265 supported.
- Bitrate: ~6–12 Mbps for 1080p9:16.
- Audio: AAC, -14 LUFS integrated. Music must be from the in-app library or licensed; copyright detection is aggressive.
- Captions: in-app captions or burned-in. Hooks in first 1.5 seconds are non-negotiable.
Instagram — Reels, Stories, Feed
Instagram has three different video surfaces with three different specs. Reels are the volume play — vertical, scrollable, the feature Meta is investing in. Stories are ephemeral and 24-hour. Feed video is the legacy in-grid format.
- Reels — 9:16, 1080×1920, up to 90 seconds (3 minutes for some accounts). H.264, MP4, ~10 Mbps. -14 LUFS audio. Burned-in captions strongly recommended.
- Stories — 9:16, 1080×1920, up to 60 seconds per segment. Same codec specs as Reels. Stickers and interactive elements via the in-app composer.
- Feed video — 4:5 (1080×1350) recommended for max visual real estate; 1:1 (1080×1080) and 16:9 (1080×608) supported. Up to 60 minutes. Bitrate 5–10 Mbps.
X (Twitter)
- Aspect ratio: 16:9 preferred; 1:1 and 9:16 supported.
- Resolution: 1280×720 minimum, 1920×1080 recommended.
- Length: 2 minutes 20 seconds for free accounts; longer for verified.
- File size: up to 512 MB.
- Codec: H.264, MP4, AAC audio.
- Bitrate: 5–25 Mbps depending on resolution.
- Audio: -14 LUFS, AAC at 128 kbps minimum.
- Aspect ratio: 16:9 standard, 1:1 for feed, 9:16 supported on mobile.
- Resolution: 1920×1080 recommended.
- Length: 30 seconds to 10 minutes for organic posts; up to 30 minutes for some account types.
- File size: up to 5 GB.
- Codec: H.264, MP4.
- Bitrate: 8–12 Mbps for 1080p.
- Audio: AAC stereo, -16 LUFS integrated (LinkedIn audiences tend to scroll without sound — burn captions).
- Captions: SubRip (.srt) upload supported. Burned-in captions perform better.
- Aspect ratio: 16:9 (Feed), 9:16 (Reels and Stories), 1:1 (Feed legacy).
- Resolution: 1920×1080 for 16:9, 1080×1920 for 9:16.
- Length: up to 240 minutes for Page videos; 90 seconds for Reels.
- File size: up to 10 GB.
- Codec: H.264, MP4 or MOV. AAC audio.
- Bitrate: 8–12 Mbps for 1080p.
- Audio: -14 to -16 LUFS.
- Aspect ratio: 9:16 strongly preferred (best feed performance); 1:1 and 2:3 supported.
- Resolution: 1080×1920 for 9:16.
- Length: 4 to 60 seconds for Idea Pins; up to 15 minutes for standard video Pins.
- File size: up to 2 GB.
- Codec: H.264, MP4 or MOV.
- Bitrate: 8 Mbps for 1080p.
- Audio: optional but increasingly expected; -14 LUFS.
Repurposing one master into every aspect ratio
Most creators do not edit a separate cut for every platform. The efficient workflow: master the project at the largest source resolution you have (4K or 1080p), shoot the original footage with safe-zones in mind so the subject sits in the central 9:16 region of the frame, and use an aspect-ratio converter to derive each platform's cut from the master. Skrrol's aspect-ratio converter applies smart re-framing — it tracks the subject and shifts the crop to keep them centered as the canvas shape changes — so you do not have to manually keyframe pan-and-scan for each platform variant. One edit, six deliverables, fifteen minutes of conversion time.
Two practical tips. Always burn captions on the shorter-form platforms (Shorts, Reels, TikTok, Stories); audiences scroll with sound off and the caption is what stops them. Always check the audio LUFS target per platform; -14 LUFS is the modern broadcast loudness standard and matches YouTube, TikTok, Reels, and X. LinkedIn and some podcast apps target -16 LUFS, which is slightly quieter. Never master at -23 LUFS (the broadcast TV standard) for social — your video will sound underpowered next to everything else in the feed.
Captions, accessibility, and silent autoplay
An estimated 75–85% of mobile video plays start muted. The platform decides for you, the user does not have time to find the unmute toggle, and the algorithm scores retention based on whether the user keeps watching anyway. Burned-in captions are the single biggest lever you have on retention because they are what the muted user reads. Auto-captions from the in-app uploader are passable for English with clear audio; they fail on accents, technical terms, and anything noisy. The professional workflow is to use Skrrol's subtitle generator on your master, hand-correct any errors, then either burn the captions onto the export (for short-form) or upload them as a sidecar .srt file (for long-form).
Beyond literal captions, accessibility means a few other things that actually move the needle. High-contrast text — white text on a 60% opacity black plate, or black text on a 60% white plate — is readable at every screen size. Sans-serif fonts at 32–48 pixel size at 1080p translate to legible text on a phone. Avoid styling caption text with thin outlines and shadows that disappear at low bitrate; the platform's compression will eat those details. And if you have music as a bed, dip it 6–8 dB during dialog so the captions and the audible track stay in sync for any user who does choose to unmute.
Thumbnails, cover frames, and the first second
Every platform either auto-picks a thumbnail or lets you upload one — and on every platform the thumbnail is 30–50% of the click-through rate. YouTube long-form gets a custom thumbnail at 1280×720 in 16:9 with high contrast, large readable text, and one clear face or focal point. YouTube Shorts and TikTok use the first frame as the cover, so make the first frame a deliberately composed beat — a face, a question, a visual hook — not the middle of an action. Reels lets you pick any frame from the video as the cover or upload a separate cover image. Stories are ephemeral and do not need a cover.
The first 1.5 seconds determine whether someone keeps watching. The hook is the most important edit decision in any short-form video and the most under-used by creators trained on long-form. A hook can be visual (an unexpected angle, a sudden movement, a surprising face), verbal (a question, a claim, a count-up), or contextual (a captioned promise of what the video is about). Generic openings — 'hey guys, today I want to talk about' — kill retention before the algorithm has a chance to surface the video. Cut into the action; explain later.
How platform compression actually works
Every platform re-encodes every upload. There is no 'lossless' path — even if you upload a 100 Mbps master, the platform will transcode it to several adaptive-bitrate ladders for delivery. The trick is to upload at a bitrate the platform respects without overshooting into the range where the encoder treats your file as low priority. For 1080p, ~12 Mbps is the sweet spot for YouTube, TikTok, and Reels — high enough that the platform's encoder uses your bits efficiently, low enough that the upload finishes quickly. Going to 50 Mbps does not yield a better-looking final on social; the platform will throw most of those bits away.
Two practical fixes for compression artifacts. First, denoise lightly before export. Random noise and grain compress poorly and turn into mushy blocks; a tiny amount of denoise (0.3–0.5 pixel radius) cleans grain without softening detail and gives the encoder cleaner signal to compress. Second, avoid extreme contrast in shadows for 9:16 short-form. The Reels and TikTok encoders are aggressive on dark frames; if you have crushed blacks with subtle detail, that detail will smear. Lift shadows slightly for these formats and the encoder will preserve them.