Social media video specs 2027: lengths, ratios, captions

A spec sheet is worth what its date is worth. Every figure below was checked in September 2026 and needs a quarterly recheck before you paste a number into a client brief. For stills on the same account, the social media image sizes cheat sheet is the sibling of this page.

In short:

• 9:16 is the ratio every platform with a published spec recommends. LinkedIn publishes a window of 1:2.4 to 2.4:1 instead.
• The binding ceilings are 60 seconds for Bluesky and 90 seconds for Facebook Reels, so one 60-second vertical cut covers every destination below.
• The sheet was checked 2026-09-20 and needs a quarterly recheck. A figure older than three months is a claim, not a fact.

Social media video specs change every quarter, so date the sheet before you trust it

The figures here were checked on September 20, 2026. Meta and X pages were only reachable as archived snapshots, so those rows deserve a live re-check first.

9:16 first is the default, and LinkedIn is the exception

Instagram recommends 9:16 “to avoid cropping or blank space”. Facebook Reels publishes 9 x 16, Threads recommends 9:16, and Pinterest recommends 9:16 or 1080x1920 for full-bleed video.

LinkedIn is where the pattern stops: its window of 1:2.4 to 2.4:1 contains 9:16, 4:5, 1:1 and 16:9 without favoring any, so shoot vertical and crop to 4:5 when the frame wastes the shot.

The spec table, platform by platform

Ten destinations, one row each, with the source and check date attached. The Instagram and Facebook rows come from Meta references archived in 2026, so confirm both live.

Platform	Aspect ratio	Max duration	Size and format	Source
YouTube Shorts	Square or vertical	3 minutes	1080p max upload resolution; 15 shorts per Studio upload	YouTube Help 2026-09-20
YouTube long-form	16:9 standard	12 hours or 256 GB, whichever is less; 15 minutes until verified	MPEG-2 or MPEG-4 preferred; no letterbox bars	YouTube Help 2026-09-20
TikTok	360 px to 4096 px	3 minutes for all creators, 5 or 10 for some, up to 10 through the API	MP4, WebM or MOV; H.264; 23 to 60 FPS; 4 GB	TikTok docs, 2026-08-04
Instagram Reels (API)	9:16 recommended, required between 0.01:1 and 10:1	15 minutes maximum, 3 seconds minimum	MOV or MP4, moov atom first; AAC 48 kHz max; HEVC or H264; 1920 px max width; 300 MB	Meta API ref, 2026-05-13 snapshot
Facebook Reels (API)	9 x 16	3 to 90 seconds, 60 if published as a Page story	.mp4; 1080x1920 recommended, 540x960 minimum; 24 to 60 fps; AAC LC 128 kbps	Meta Reels guide, 2026-04-18 snapshot
X	1280x720 landscape or 720x720 square (Media Studio)	140 seconds standard, under 4 hours at 1080p on Premium	512 MB standard, 16 GB Premium, 8 GB library; AVC H264, 60 FPS max	X Help, snapshots 2026-09-08 and 2026-03-23
LinkedIn organic	1:2.4 to 2.4:1	15 minutes maximum; 3 s desktop minimum, 2 s in app	5 GB maximum, 75 KB minimum; 10 to 60 fps	LinkedIn Help, 2026-09-20
Pinterest video Pins	9:16 or 1080x1920 recommended; also 1:2, 2:3, 3:4, 4:5, 1:1	4 seconds minimum, 5 minutes maximum	.MP4 and .M4V on web, .MOV on mobile; H.264 or H.265; safe zone 270 px top, 65 px left, 195 px right, 790 px bottom	Pinterest Help, 2026-09-20
Threads	9:16 recommended, required between 0.01:1 and 10:1	300 seconds maximum	MOV or MP4, moov atom first; 1 GB; 100 Mbps maximum video; 23 to 60 FPS	Meta Threads guide, 2026-08-20 snapshot
Bluesky	Aspect ratio supplied by the publisher on embeds	60 seconds	One video per post; .mp4, .mpeg, .webm, .mov; 25 videos or 10 GB per day; email verified	Bluesky post 2024-09-11, docs 2026-09-20

The table was checked in September 2026 and needs a quarterly recheck.

The Bluesky figures come from a page dated September 2024, making them the oldest numbers here and possibly stale. Press reports in late August 2026 describe a raised limit of 10 minutes and 300 MB, but no official page confirming it could be retrieved on 2026-09-20, so it is not printed as spec.

Where platforms publish nothing: Meta does not publish a spec table for organic feed video on Instagram or Facebook, so no feed row appears above. Pinterest, Threads and the Meta Reels paths publish no caption requirement, and X publishes no per-post video count.

YouTube Shorts: three minutes, and the platform decides what counts

YouTube states that Shorts run up to three minutes, and that any video uploaded on or after its cut-off date with “a square or vertical aspect ratio up to three minutes in length will be categorized as Shorts”. That date is October 15, 2024 for standard channels and December 8, 2025 for Official Artist Channels; earlier uploads stay long-form.

You do not choose to publish a Short: square or vertical under three minutes gets filed as one, which is why a 16:9 clip never becomes a Short. Shorts uploads cap at 1080p, and any Short over one minute with an active copyright claim is blocked globally.

TikTok photo and text posts cover the slots video cannot

Photo posts take up to 35 images and text posts let you set font, size, style and color, with alt text up to 300 characters per description. Through the API, images must be WebP or JPEG, at most 1080p and 20 MB each.

Keep them in the plan for framing reasons: a carousel or text post has no vertical frame to fill, so it is the fallback when landscape footage cannot be reframed without losing the point. TikTok also caps publishing at typically around 15 posts per 24 hours per creator, shared across API clients.

One master edit and a cutting map beats five separate exports

Start from one master timeline, reframe once, lay one caption track, then export. YouTube’s guidance is the reason: upload in native aspect ratio and never include letterboxing or pillarboxing bars, because baked-in padding stops the player adapting the frame. Cut a square or 9:16 master with the subject centered and treat 16:9 as a deliverable.

Export	Canvas	Ceiling to respect
Short-form master	1080x1920	60 seconds for Bluesky, 90 seconds for Facebook Reels, 3 minutes for YouTube Shorts, 5 minutes for Pinterest and Threads
Vertical short cut	1080x1920	60 seconds, which clears every destination above
Feed cut	1080x1350 or 1080x1080	Same file as the master; inside the LinkedIn window and on the Pinterest ratio list
Watch-page cut	1920x1080	Long-form rules; YouTube ratio, no bars
Series settings	24 or 30 fps; AAC 48 kHz stereo at 128 kbps or higher; MP4 with H.264 and the moov atom at the front	Sits inside 23 to 60 FPS for TikTok, Instagram and Threads, 10 to 60 for LinkedIn organic

Pinterest is the only destination that publishes safe-area numbers: 270 px top, 65 px left, 195 px right, 790 px bottom. LinkedIn publishes a rule instead, asking you to keep the edges free of key elements, text and logos. TikTok publishes a procedure, saying the zone depends on the dimension, the ad caption length and any additional formats.

Instagram Reels, Facebook Reels, YouTube Shorts, X, Threads and Bluesky publish no safe-area rectangle. Since Pinterest is the only source of pixel insets and TikTok’s zone shrinks as captions grow, keep text inside the region the published templates share and treat the bottom fifth of the canvas as reserved.

Once the exports are named, producing a month of them is a scheduling task, which batching a month of content covers, and repurposing handles the source side.

Captions are a spec item, not a finishing touch

Captions are a spec item because half the destinations publish nothing about them. Five document support: X takes CEA 608/708 tracks and an .SRT sidecar, LinkedIn auto-generates captions in 10 languages or takes a caption file, YouTube accepts .srt and .vtt, TikTok auto-generates them for uploads, and Bluesky lets you attach subtitles. Pinterest, Threads and Meta feed video publish nothing, so a burn-in is the only guaranteed text there.

That makes the export list two items from one edit: a sidecar SRT and a styled burn-in. Keep the burn-in inside the same safe region as your titles, and note that LinkedIn ad captions must be an SRT of plain text with no custom formatting. Post text limits live on the character limits by network page.

PostSider shows a per-platform preview in the composer, so the caption crop and frame edges are visible before a post is queued.

What actually gets an upload rejected

X returns “Video too long”; uploads fail on file size, resolution or encoding settings. Processing stalled at 5 percent can time out after up to 30 minutes, most often with .mov files, which an .mp4 re-export fixes. LinkedIn errors on unsupported file types, noting that ProRes may upload but will not process and that leaving the iOS app mid-upload can stall it.

Elsewhere the envelope is arithmetic. YouTube needs anything above 256 GB compressed first and holds unverified accounts at 15 minutes. The TikTok API rejects files above 4 GB, frames outside 23 to 60 FPS and pictures outside 360 px to 4096 px. Instagram rejects a ratio outside 0.01:1 to 10:1 and expires an unpublished container after 24 hours. Pinterest fails a video under 4 seconds or over 5 minutes, Threads rejects files above 1 GB or 300 seconds, and a failed Bluesky processing job shows a missing video until you re-upload.

The sheet is the deliverable: a 9:16 master, a 60-second vertical cut, 24 or 30 fps, MP4 with H.264 and the moov atom at the front, one SRT and one burn-in. PostSider connects 30+ networks from one composer, keeps video in the media library with media types tracked, and accepts uploads from a public URL through the public API. Instagram publishing needs a Business or Creator account. Plans run Standard at $20, Team at $35, Pro at $45 and Ultimate at $90, each with a 7-day trial; details sit on the pricing page.

Lukasz Blania is the founder of PostSider, a scheduling and publishing tool for teams and the agents that work with them. He writes from the platform documentation, dates every figure, and re-checks this sheet each quarter.