LinkedIn Video Specs: Size, Length and Captions

LinkedIn has started paying some creators when ads run on their videos, which makes it worth getting the format right. LinkedIn video specs come in two sets, one for ordinary posts and a stricter one for ads, and the two are easy to mix up. Here is what LinkedIn announced, both sets of numbers, which shape to use, and how to handle captions.

What LinkedIn announced

On 15 October, LinkedIn announced a test of In-Stream Ads: pre-roll video ads that run alongside eligible creator videos, with the creator earning revenue when they do. It is open to invited creators, and LinkedIn says it is being tested among select US creators and advertisers, with broader access planned over time. MediaPost described it as a handful of creators to begin with.

LinkedIn has not published a revenue share or the criteria for eligibility. Invited creators join from a new creator dashboard, which LinkedIn says is rolling out globally in the coming weeks.

None of that changes the format rules. But a video that might carry an ad, and earn from it, is one worth formatting properly.

LinkedIn's limits for video posts

LinkedIn's help page on sharing video lists the limits for an uploaded video. The page says it was last updated about two years ago, so treat these as LinkedIn's stated limits and check them if a file is rejected:

• Length: 3 seconds minimum on desktop and 2 in the mobile app, up to 15 minutes.
• File size: 75 KB to 5 GB.
• Aspect ratio: anything from 1:2.4 to 2.4:1.
• Resolution: 256 x 144 up to 4096 x 2304.
• Frame rate: 10 to 60 frames per second.
• Bitrate: 192 Kbps to 30 Mbps.
• Formats: MP4 among many others, including MOV and WEBM.

That aspect range is generous. Vertical 9:16, tall 4:5, square 1:1 and widescreen 16:9 all fall inside it.

The stricter specs for video ads

If you also run video ads, LinkedIn's video ad specs are tighter, and they are not the same as the posting limits:

• Shapes: 16:9 at 1920 x 1080; 1:1 up to 1920 x 1920; 4:5, which LinkedIn calls the recommended ratio, at 720 x 900 and up to 1080 x 1350; and 9:16 at 720 x 1280 and up to 1080 x 1920.
• Length: 3 seconds to 30 minutes, with 15 to 30 seconds recommended to qualify for all placements. In-stream video ads can be up to 90 seconds.
• File: MP4, H.264 or VP8, under 30 frames per second, 75 KB to 500 MB.
• Captions: an SRT file, text only, with no custom formatting.

The two lists disagree in places. An ordinary post can run 15 minutes at up to 60 frames per second; an ad can run 30 minutes but must be under 30 frames per second. Check which set applies to the file in front of you.

Which shape to use

For ordinary posts, LinkedIn's limits accept every common shape, so the choice is about the viewer.

• Most of your audience on phones: a taller shape takes more of an upright screen. 4:5 or 1:1 fills far more of a phone than 16:9 does, and 4:5 is the shape LinkedIn recommends for ads.
• A talk, a demo or a screen recording watched on desktop: 16:9 keeps text and detail legible.
• One edit, several shapes: you do not have to choose once. The same timeline can be exported at several ratios.

Captions on LinkedIn

The posting limits say nothing about captions. For ads, LinkedIn wants captions as a separate text-only SRT file.

flshy's captions are burned into the picture: every cue is a text clip drawn into the frame when you export. That works for any post, because the words are part of the video and need no caption support from the player. The trade is that viewers cannot switch them off, which our post on burned-in captions vs closed captions weighs up. For an ad with an uploaded SRT file, burned-in captions are not a substitute for the file LinkedIn asks for.

Preparing a LinkedIn video in flshy

This runs free in flshy, in the browser, with your footage staying on your own machine.

1. Cut the dead air. Open the Audio tab and use Remove silent gaps. See remove silence from a recording.
2. Caption it at its final length. Generate captions on your device, press the button under the transcript that reads Add 24 as Editable Text, or whatever your count is, and fix any names. See add captions to a video.
3. Choose the shape. In the AI tab, open Advanced and expand Auto Reframe. flshy's LinkedIn preset is for landscape 16:9. For a taller post, pick a raw ratio instead: 4:5 for 1080 x 1350, 1:1 for 1080 x 1080, or 9:16 for 1080 x 1920. The detail is in turn a landscape video vertical.
4. Move the captions if the shape changed. Reframing changes the canvas, so check the captions and use the Properties tab to move them where nothing covers them.
5. Export, then check the file. flshy exports H.264 MP4 up to 4K with no watermark. Our guides do not list the export's bitrate or frame rate, so for an ad in particular, check the finished file against LinkedIn's limits: under 500 MB, under 30 frames per second, and no larger than the maximum size for its shape, such as 1080 x 1350 for 4:5.

If you are also cutting the same footage for Reels, our post on turning horizontal video into full-screen Reels covers the vertical version.