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Ad specs builder

Pick the platforms you are running and the ad types you are making. You get exactly those specs and nothing else: ratio, export size, file caps, video length, character limits and the safe zone. One answer per field, not a list of what each platform says on which page.

1

Platforms

pick as many as you need
2

Ad types

image, video, carousel

Other formats covers the ones that are their own thing: Snapchat Story and Collection ads, LinkedIn document, message and right rail ads.

43 placements

Every figure below is the one we would build to. Where a platform contradicts itself, the line under the card says which reading we took and why.

Facebook

Feed

Image
Ratio4:5
Export at1440 × 1800
File
JPG or PNG, up to 30MB
Minimum
600px wide
Ratio tolerance
3%
Safe zone
Nothing sits over a Feed ad.

Character limits

  • Primary text125
  • Headline27
  • Description25

Add a call to action and the button row is counted inside the ad block, so a 4:5 upload is cropped back to a square. Export 1:1 and you lose nothing. Meta does not publish this. We see it in live delivery.

Ads Guide Facebook Feed image page. Meta’s cross placement table also marks 4:5 recommended.

Facebook

Feed

Video
Ratio4:5
Export at1440 × 1800
Length
1 second to 241 minutes, keep it under 15
File
MP4, MOV or GIF, up to 4GB
Minimum
120px wide
Safe zone
Nothing sits over a Feed ad.

Character limits

  • Primary text125
  • Headline27
  • Description25

On the Awareness objective the whole footer disappears on mobile: headline, description and button. Your video is the entire ad.

Ads Guide Facebook Feed video page.

Facebook

Feed

Carousel
Ratio1:1
Export at1080 × 1080 or larger
Length
1 second to 240 minutes, 15 seconds recommended
Cards
2 to 10
File
JPG or PNG for images, MP4 or MOV for video
Ratio tolerance
3%
Safe zone
Card counter and swipe affordance sit over the creative.

Character limits

  • Primary text125
  • Headline27 per card
  • Description25 per card

Images and video can be mixed in one carousel, each card with its own headline, link and button. Meta may reorder the cards and start on whichever it thinks that person will respond to, and may render the whole thing as a slideshow video instead.

Ads Guide carousel Facebook Feed page. Meta’s cross platform design spec adds 4:5 and 9:16, but no individual Facebook placement page mentions either, so 1:1 is the safe build.

Facebook

Stories

Image
Ratio9:16
Export at1440 × 2560
File
JPG or PNG, up to 30MB
Minimum
500px wide
Ratio tolerance
1%
Safe zone
14% top, 14% bottom, measured.

Character limits

  • Primary text125
  • Headline40

Shows for 8 seconds or until the person swipes out. Meta publishes 14 / 20 on the video page and 14 / 35 / 6 on the image page for the same placement. Its own Ads Manager guardrail draws 14 / 14 and no side margin at all.

Ratio and size from the Ads Guide. Safe zone measured by us off Meta’s guardrail on 14 Aug 2026, because that is what the ad runs against.

Facebook

Stories

Video
Ratio9:16
Export at1440 × 2560
Length
1 second to 2 minutes
File
MP4, MOV or GIF, up to 4GB
Minimum
250px wide
Ratio tolerance
1%
Safe zone
14% top, 14% bottom, measured.

Character limits

  • Primary text125
  • Headline40

Anything over 15 seconds is split into separate Stories cards, so write to a 15 second beat. Meta gives 3 minutes on the Ads Guide and 120 seconds on its cross placement table. Build to 120.

Shorter of Meta’s two published maximums.

Facebook

Stories

Carousel
Ratio9:16
Export at1080 × 1920 or larger
Cards
2 to 3
File
JPG or PNG. Video is not supported.
Safe zone
14% top, 14% bottom, measured.

Character limits

  • Primary text125
  • Headline40

The first card shows, then the viewer taps for the rest. Meta says 3 to 10 cards on one page and up to 3 on another, and gives 1:1 on one and 9:16 on the other, each contradicting its own recommended resolution. Three 9:16 cards is the build that is valid under every reading.

The intersection of both Meta pages.

Facebook

Reels

Image
Ratio9:16
Export at1440 × 2560
File
JPG or PNG, up to 30MB
Minimum
600px wide
Ratio tolerance
3%
Safe zone
14% top, 40% bottom, 6% sides, measured. Plus the action rail down the right.

Character limits

  • Primary text40
  • Headline55

Meta publishes 35% at the bottom. Its own guardrail draws 40%. Neither draws the like, comment, share and audio icons stacked down the right, which are there the whole time your ad is running.

Deeper of Meta published and Meta measured.

Facebook

Reels

Video
Ratio9:16
Export at1440 × 2560
Length
No maximum stated
File
MP4, MOV or GIF, up to 4GB
Safe zone
14% top, 40% bottom, 6% sides, measured. Plus the action rail down the right.

Character limits

  • Primary text40
  • Headline55

Auto captioning is not supported here, so burn your captions in. Sound is close to mandatory in Reels.

Deeper of Meta published and Meta measured.

Facebook

Marketplace

Image
Ratio1:1
Export at1080 × 1080 or larger
File
JPG or PNG, up to 30MB
Safe zone
Nothing published.

Character limits

  • Primary text125
  • Headline40
  • Description25

Meta recommends 1200 × 1200 as the minimum here, higher than the 1080 it asks for elsewhere.

Ads Guide Marketplace pages.

Facebook

Marketplace

Video
Ratio1:1
Export at1080 × 1080 or larger
Length
1 second to 241 minutes
File
MP4, MOV or GIF, up to 4GB
Minimum
120px wide
Safe zone
Nothing published.

Character limits

  • Primary text125
  • Headline25

Meta’s Marketplace video page drops the primary text row entirely and gives a shorter headline than the image page for the same placement. Write to 25.

Shorter headline of the two Marketplace pages.

Facebook

In-stream video

Video
Ratio16:9 or 1:1
Export at1080 × 1080 or larger
Length
5 to 15 seconds on desktop, 5 seconds to 10 minutes on mobile
File
MP4, MOV or GIF, up to 4GB
Safe zone
Nothing published.

Character limits

  • Primary text125
  • Headline40
  • Description25

Skippable after 5 seconds and truncated at 15 on desktop. Everything that matters goes in the first 5 seconds. Sound is strongly recommended here because the viewer already had sound on.

Ads Guide in-stream video page.

Instagram

Feed

Image
Ratio4:5
Export at1440 × 1800
File
JPG or PNG, up to 30MB
Minimum
500px wide
Ratio tolerance
1%
Safe zone
Nothing sits over a Feed ad.

Character limits

  • Primary text125
  • Headline40
  • Hashtags30 maximum

Add a call to action and the button row is counted inside the ad block, so a 4:5 upload is cropped back to a square. Export 1:1 and you lose nothing. Meta does not publish this. We see it in live delivery. Meta also says 4:5 on the Ads Guide and 1:1 on its own best practice page.

Ads Guide Instagram Feed image page. Range is 4:5 to 1.91:1.

Instagram

Feed

Video
Ratio9:16
Export at1080 × 1920
Length
1 second to 60 minutes
File
MP4, MOV or GIF, up to 4GB
Minimum
250px wide
Ratio tolerance
1%
Safe zone
A 9:16 video in Feed uses the same 14 / 35 / 6 as Reels and Stories, per Meta.

Character limits

  • Primary text125
  • Hashtags30 maximum

This is the one Feed case with a safe zone. Meta states plainly that 9:16 video in Instagram Feed follows Reels and Stories guidance, so a vertical video here is not a wrong shape, it is a supported case with a different rule.

Ads Guide Instagram Feed video page plus Help Centre 980593475366490.

Instagram

Feed

Carousel
Ratio4:5, or 1:1 the moment any card is video
Export at1080 × 1080 or larger
Length
1 second to 2 minutes, 15 seconds recommended
Cards
2 to 10
File
JPG or PNG for images, MP4 or MOV for video
Ratio tolerance
1%
Safe zone
Card counter and swipe affordance sit over the creative.

Character limits

  • Primary text125
  • Headline40 per card
  • Hashtags30 maximum

One video card drags the entire carousel from 4:5 to 1:1, including the image cards. That is 20% of the vertical space on every card, paid for by one video. Nobody publishes this as a planning rule but it is on Meta’s own page.

Ads Guide carousel Instagram Feed page, quoted directly.

Instagram

Stories

Image
Ratio9:16
Export at1440 × 2560
File
JPG or PNG, up to 30MB
Minimum
500px wide
Ratio tolerance
1%
Safe zone
14% top, 35% bottom, 6% sides.

Character limits

  • Primary text125

Shows for 5 to 16 seconds. This is the one vertical placement where Meta’s published figure is the deeper one: its own guardrail draws only 20% at the bottom. We keep 35 because that is what Meta tells the world and it costs you nothing to clear it.

Deeper of Meta published and Meta measured.

Instagram

Stories

Video
Ratio9:16
Export at1440 × 2560
Length
1 second to 60 minutes
File
MP4, MOV or GIF, up to 4GB
Minimum
250px wide
Ratio tolerance
1%
Safe zone
14% top, 35% bottom, 6% sides.

Character limits

  • Primary text125

Anything 16 seconds or longer may be split into separate Stories cards, so write to a 15 second beat.

Deeper of Meta published and Meta measured.

Instagram

Stories

Carousel
Ratio9:16
Export at1080 × 1920 or larger
Length
1 second to 15 seconds
Cards
2 to 3
File
JPG or PNG for images, MP4 or MOV for video
Ratio tolerance
1%
Safe zone
14% top, 35% bottom, 6% sides. Plus the Expand story prompt.

Character limits

  • Primary text125

Build 3. Meta gives three different card counts across three of its own pages, and only shows 1 to 3 before the viewer has to tap Expand story. If Instagram Stories is your only selected placement you can fix the count at 3 instead of letting Meta decide per person.

Our rule, not Meta’s. Three is the count that always displays and is valid under all three of Meta’s answers.

Instagram

Reels

Image
Ratio9:16
Export at1440 × 2560
File
JPG or PNG, up to 30MB
Minimum
500px wide
Ratio tolerance
1%
Safe zone
15% top, 35% bottom, 6% sides. Plus the action rail down the right.

Character limits

  • Primary text44

44 characters of primary text is the shortest field anywhere on Meta. Write the hook, nothing else.

Deeper of Meta published and Meta measured.

Instagram

Reels

Video
Ratio9:16
Export at1440 × 2560
Length
Up to 15 minutes
File
MP4 or MOV. No GIF.
Minimum
250px wide under 30 seconds, 500px at 30 seconds or longer
Ratio tolerance
1%
Safe zone
15% top, 35% bottom, 6% sides. Plus the action rail down the right.

Character limits

  • Primary text44

Meta rejects Reels ads built from a Reel published before 15 Oct 2021, or containing licensed music, a camera effect, a face effect, a GIF or product tags.

Deeper of Meta published and Meta measured.

Instagram

Explore home

Image
Ratio4:5
Export at1440 × 1800
File
JPG or PNG, up to 30MB
Minimum
500px wide
Ratio tolerance
1%
Safe zone
Nothing published.

Character limits

  • Primary text125
  • Headline40
  • Hashtags30 maximum

Instagram Explore stopped being a selectable placement in January 2026. Explore home is the one that remains.

Ads Guide Explore home page.

Instagram

Explore home

Video
Ratio9:16
Export at1080 × 1920
Length
1 second to 60 minutes
File
MP4, MOV or GIF, up to 4GB
Minimum
250px wide
Ratio tolerance
1%
Safe zone
Nothing published.

Character limits

  • Primary text125

Ads Guide Explore home page.

TikTok

In-feed

Video
Ratio9:16
Export at1080 × 1920, minimum 540 × 960
Length
5 to 60 seconds, 9 to 15 recommended
File
MP4, MOV, MPEG or 3GP, up to 500MB. Bitrate 516 kbps or higher.
Safe zone
12.8% top, 37.4% bottom, measured.

Character limits

  • Caption100, no hashtags and no emojis
  • Account name20

TikTok reserves a fixed part of the phone screen, not a percentage of your file, so the same zone cuts a 9:16 and a 1:1 in completely different places. On a square it starts above your creative, takes 27% off the bottom and adds a rail across nearly a third of the width. TikTok also scales a 9:16 to fill a taller device and crops about 11% of the width, so your side margins can leave the screen entirely.

5 to 60 seconds is TikTok’s ad policy page and four spec pages. One page says 10 minutes. Safe zone measured by us, 19 Aug 2026: TikTok publishes no numbers, only templates.

TikTok

In-feed, Spark Ads

Video
RatioWhatever the organic post is
Export atNo re-export, the post is the ad
Length
Up to 10 minutes
File
MP4 or MOV
Safe zone
12.8% top, 37.4% bottom, measured.

Character limits

  • CaptionInherited, 4 lines shown

The caption is pulled from the organic post and cannot be edited once authorised. Unlike a normal in-feed ad, a Spark caption keeps its hashtags, mentions and emojis, because it is the real post.

TikTok’s Spark Ads page. Its in-feed page says no restrictions on duration, the Spark page says 10 minutes. Build to 10.

TikTok

TopView

Video
Ratio9:16
Export at1080 × 1920, minimum 540 × 960
Length
5 to 60 seconds, 9 to 15 recommended
File
MP4, MOV, MPEG or 3GP, up to 500MB. Bitrate 2500 kbps or higher.
Safe zone
12.8% top, 37.4% bottom, measured.

Character limits

  • Caption100
  • Account name20

Emojis and full width characters count as two each, which is the only place TikTok says how it counts. TopView asks for a higher bitrate than auction in-feed, 2500 against 516.

TikTok TopView specification page.

TikTok

Carousel

Carousel
Ratio9:16 preferred
Export at720 × 1280 vertical, 640 × 640 square, 1200 × 628 horizontal
Cards
2 to 35
File
JPG or PNG, 100KB or under suggested
Safe zone
12.8% top, 37.4% bottom, measured.

Character limits

  • CaptionOne caption and one button for the whole set

Images only, no video cards. Music is mandatory and must be at least 2 seconds, either from TikTok’s commercial library or uploaded. Vertical is preferred because anything else gets black bars in the feed.

TikTok carousel specification page. The catalog version of carousel caps at 20 cards, not 35.

TikTok

Profile photo

Other formats
Ratio1:1
Export at98 × 98
File
JPG or PNG, under 50KB
Safe zone
Keep the key element inside the middle 66 × 66.

The only numeric safe zone TikTok publishes anywhere, and it is for the avatar rather than the ad.

TikTok in-feed specification page.

Snapchat

Single Image or Video

Image
Ratio9:16
Export at1080 × 1920, minimum 720 × 1280
File
JPG or PNG, up to 5MB
Safe zone
10% top, 35% bottom, 6% sides, measured. Plus the action rail on the right.

Character limits

  • Brand name25
  • Headline34

A still is converted to a 5 second video. Snapchat runs one safe zone across Stories, Spotlight and Commercials, and we measured six different setups to confirm it: they agree to within 0.4 of a point. It is the only platform whose documentation and whose own tool actually match.

Brand name is 32 in Snapchat’s help centre and 25 on its own marketing site. We print 25 because it is safe under both.

Snapchat

Single Image or Video

Video
Ratio9:16
Export at1080 × 1920, minimum 720 × 1280
Length
3 seconds to 3 minutes, 3 to 5 recommended
File
MP4 or MOV, H.264, up to 1GB
Safe zone
10% top, 35% bottom, 6% sides, measured. Plus the action rail on the right.

Character limits

  • Brand name25
  • Headline34

Audio has a real spec here and Snapchat enforces it: two channels, balanced, target level minus 16 LUFS, AAC or PCM at 192 kbps or higher. Anything under 3 seconds is looped up to 3.

Snapchat’s spec page says 30 minutes, its Story Ad page and its marketing site both say 180 seconds. We print 180.

Snapchat

Story Ad

Other formats
Ratio9:16
Export at1080 × 1920
Length
Up to 3 minutes per Snap
Cards
1 to 10 Snaps
File
MP4 or MOV for video, JPG or PNG for stills
Safe zone
10% top, 35% bottom, 6% sides, measured.

Character limits

  • Brand name25
  • Headline34
  • Tile headline55, emojis count

The Discover tile is a separate asset: 360 × 600 PNG under 2MB, with a 175px clear zone at the top and 269px at the bottom. Skip the tile only if you are running between content and nothing else.

Snapchat Story Ad specification page.

Snapchat

Collection Ad

Other formats
Ratio9:16
Export at1080 × 1920
Cards
2, 3 or 4 tiles
File
Tiles are square JPG or PNG, 2MB or less each, 160 × 160 or larger
Safe zone
10% top, 35% bottom, 6% sides, measured. Same as a plain Snap Ad.

Character limits

  • Brand name25
  • Headline34

The tiles do not cost you room. We measured a Collection Ad against a plain Snap Ad and they are identical: the tile row sits inside the 35% Snapchat already reserves. Every designer assumes otherwise. Each tile needs its own URL, and Snapchat puts the Ad slug top right and the button top left of the tile row.

Measured by us in Snapchat Ads Manager on 19 Aug 2026.

Snapchat

Commercial

Video
Ratio9:16
Export at1080 × 1920
Length
3 to 6 seconds standard, 7 to 180 extended
File
MP4 or MOV, H.264, up to 1GB. Video only, must have audio.
Safe zone
10% top, 35% bottom, 6% sides, measured. A 6 second ticker runs across the top.

Character limits

  • Brand name25
  • Headline34

A standard Commercial is non skippable end to end. An extended one is non skippable for the first 6 seconds only, which makes 6 seconds the real length of the ad and everything after it optional. Stills, GIFs, cinemagraphs and silent video are all rejected.

Snapchat Commercial specification page.

LinkedIn

Feed

Image
Ratio1:1 or 4:5
Export at1200 × 1200 square, 720 × 900 vertical
File
JPG, PNG or GIF, up to 5MB
Safe zone
Nothing published.

Character limits

  • Intro text150
  • Headline70
  • Description70 on the audience network only

Vertical does not deliver to desktop at all. Use 4:5 rather than 1:1.91 vertical, because 1:1.91 gets bars added down both sides. LinkedIn’s own page lists three ratios at the top and five further down.

LinkedIn single image specification page, taking the technical requirements block over the summary block.

LinkedIn

Feed

Video
Ratio1:1, 4:5, 9:16 or 16:9
Export at1080 × 1080, up to 1920 × 1920
Length
3 seconds to 30 minutes
File
MP4, 75KB to 500MB. AAC or MPEG4 audio.
Ratio tolerance
5%
Safe zone
Nothing published.

Character limits

  • Intro text150, hard cap 600
  • Headline70, hard cap 200

Video is the only LinkedIn format that takes 9:16, and the only one where LinkedIn prints both a recommended and a hard maximum for the text. Frame rate 30fps. A thumbnail is optional but worth uploading.

LinkedIn video specification page. The recommended figure is printed first because that is the truncation point.

LinkedIn

Feed

Carousel
Ratio1:1
Export at1080 × 1080 or larger
Cards
2 to 10, build 3 to 5
File
JPG or PNG, up to 10MB
Safe zone
The second card shows in partial view beside the first.

Character limits

  • Intro text255
  • Headline45 per card

Carousel does not support video on LinkedIn at all. Note the intro text runs to 255 here against 150 on a single image ad, which is LinkedIn’s own difference, not an error.

LinkedIn carousel specification page. The 3 to 5 build is LinkedIn’s own best practice page.

LinkedIn

Feed, document ad

Other formats
RatioVertical, square or horizontal
Export atStandard page sizes, A4 or Letter
Cards
Under 10 pages, 300 maximum
File
PDF, DOC, DOCX, PPT or PPTX, up to 100MB
Safe zone
Nothing published.

Character limits

  • Intro text150
  • Headline70

Flatten every layer and make every page the same size or the upload fails. Under 10 pages is LinkedIn’s recommendation, 300 is the cap.

LinkedIn document ad specification page.

LinkedIn

Right rail, spotlight

Other formats
Ratio1:1 logo
Export atLogo 100 × 100, optional background 300 × 250
File
JPG or PNG, up to 2MB
Safe zone
Nothing published.

Character limits

  • Headline50
  • Description70
  • Company name25
  • Button label18

The destination URL caps at 500 characters here against 2000 on every other LinkedIn format.

LinkedIn spotlight ad specification page.

LinkedIn

Inbox, message ad

Other formats
RatioBanner 300 × 250, desktop only
Export at300 × 250
File
JPG or PNG, up to 2MB
Safe zone
Nothing published.

Character limits

  • Message body8,000
  • Custom footer20,000
  • Button label25

Message ads and conversation ads publish byte identical specs, so treat them as one format with two names. The banner never shows on mobile.

LinkedIn message ad specification page. These are stated maximums, not recommendations.

LinkedIn

Right rail, text ad

Other formats
Ratio1:1 logo
Export at100 × 100
File
JPG or PNG, up to 2MB
Safe zone
Nothing published.

Character limits

  • Headline25
  • Description75

LinkedIn text ad specification page.

X

Timeline

Image
Ratio1:1 or 16:9
Export at1200 × 1200 square, 1200 × 628 wide
File
PNG or JPEG, up to 5MB. No BMP or TIFF.
Safe zone
Nothing published for the timeline.

Character limits

  • Post copy280, 257 with a link
  • Headline70

X now accepts 4:5, 2:3, 1:1, 1.91:1, 16:9 and 9:16, so existing social creative can run without a reformat. A GIF uploads but renders as a still. Keep the logo in the top left, which is the one placement note X does publish.

X creative ad specifications, current page. Its ads API documentation gives a 3MB cap and narrower ratios, which applies to API uploads.

X

Timeline

Video
Ratio1:1 or 16:9
Export at1200 × 1200 square, 1920 × 1080 wide
Length
Up to 2 minutes 20, under 15 seconds recommended
File
MP4 or MOV, up to 1GB, keep it under 30MB. H.264, AAC LC.
Safe zone
Nothing published for the timeline.

Character limits

  • Post copy280, 257 with a link
  • Headline70

Anything under 60 seconds loops. Bitrate 6000 kbps for 1080p, 5000 for 720p, at 30fps. X prohibits hashtags and multiple emojis in ad copy, and says the best performing copy is 50 to 100 characters.

X creative ad specifications, current page.

X

Immersive feed

Video
Ratio9:16
Export at1080 × 1920, minimum 720 × 1280
Length
Up to 2 minutes 20, under 15 seconds recommended
File
MP4 or MOV. H.264, AAC LC. Target bitrate 5 to 10 Mbps, 25 maximum.
Safe zone
Roughly 12% top and 22% bottom, derived from X’s own UI map.

Character limits

  • Post copy90 before it is cut off
  • Headline70

X does not publish a safe zone. It publishes a table of UI element sizes and positions, on a legacy page it has not linked from anywhere, and you have to work the margins out yourself. The button appears one second in and stays. Caption shows 2 lines on iOS and 3 on Android before it truncates.

Derived by us from X’s published 9:16 iOS and Android UI element maps, taking the deeper of the two on each edge.

X

Timeline

Carousel
Ratio1:1 or 16:9
Export at800 × 800 square, 800 × 450 wide
Length
Up to 2 minutes 20, under 15 seconds recommended
Cards
2 to 6
File
PNG or JPEG for images, MP4 or MOV for video
Safe zone
Nothing published.

Character limits

  • Post copy280, 257 with a link
  • Headline70

Images and video can be mixed in one carousel, but every card has to be the same ratio. Up to 6 different destination URLs, one per card.

X carousel page. X never says 70 characters and per card in the same sentence, so treat the per card headline as inferred.

X

Amplify pre-roll

Video
Ratio1:1
Export at1200 × 1200, minimum 600 × 600
Length
Up to 2 minutes 20, under 15 seconds recommended
File
MP4 or MOV, up to 1GB. H.264, AAC LC.
Safe zone
Keep the corners clear on sponsorships.

Character limits

  • Post copy280, 257 with a link

Viewers can skip after 6 seconds, so the first 6 seconds are the ad. On Amplify sponsorships X puts product overlays in the top left and both bottom corners.

X creative ad specifications, current page.

The rules that are not on anybody’s spec page

One export that clears every vertical placement

9:16 at 1440 × 2560, with the top 16% clear, the bottom 41% clear, and 7% down each side. That covers Instagram and Facebook Stories and Reels, Snapchat and TikTok in one file. Instagram Reels sets the top at 15.3% measured, Facebook Reels sets the bottom at 40.4%, and Snapchat sets the sides at 6.4%. The figures here are rounded up so one number covers all of them.

One export that clears every feed

1:1 at 1440 × 1440. Square is the only shape that is never cropped anywhere, and on Facebook and Instagram it is also the shape that does not lose a strip to the call to action row.

Square is not safe on TikTok

Everywhere else a square is the safe universal export. On TikTok the safe zone is anchored to the phone rather than to your file, so a square gets a free top, loses 27% at the bottom and picks up an action rail across nearly a third of its width.

Carousel changes the frame, not just the count

One video card drops an Instagram Feed carousel from 4:5 to 1:1, on every card. LinkedIn does not take video in a carousel at all. TikTok does not either, and requires music. X takes both but every card has to be the same ratio.

Write to the shortest field, not the longest

Instagram Reels gives you 44 characters of primary text. Facebook Reels gives 40. X gives 280 but performs best at 50 to 100. If one line has to work everywhere, write it at 40.

The safe zone figures marked measured came out of the safe zone checker, where you can drop your own creative in and see them drawn on it.