What the checker reads
For each file you drop, the checker reads the size a platform will see: the width and height in pixels (after any rotation a phone recorded), the file size and, for a video, its length — and checks the file against every Facebook, Instagram, TikTok and YouTube placement that takes that kind of file, best match first.
File sizes are compared in decimal units, the stricter reading of a platform's “MB”: 1 MB = 1,000,000 bytes. A file exactly on a stated maximum, minimum or end of a range is inside it.
The verdicts
- Fits
- The file has the ratio the platform states, is at least as large as any minimum and is inside every limit. A file a pixel or two off its ratio still fits: we allow 0.5% for rounding. That allowance is ours, not the platform's.
- Fits within tolerance
- The file is off the stated ratio, but by no more than the placement's aspect ratio tolerance — 3% on a Facebook feed image, 1% on an Instagram feed image (Meta's ads guide, as of 2026-10-22). Meta's page does not define the term; this is our reading: the file's width over its height, divided by the stated ratio, may differ from one by no more than the tolerance.
- Accepted ratio
- The page accepts this shape but recommends another. Instagram's feed image page states a range, from 400 × 500 to 191 × 100, around a recommended 4:5. TikTok's in-feed page recommends 9:16 and accepts two other shapes at their own minimums.
- Below minimum
- The file is narrower or shorter than the page's minimum.
- Supported
- A shape the page's small print supports, though it recommends another; the row quotes Meta's words.
- Outside the supported ratios
- The file is outside the range of shapes the page states, in its spec or small print.
- Not the stated ratio
- The page gives one shape or a few, with no range around them, and the file is none of them. TikTok's carousel page states no ratio, so the checker treats its three sizes as shapes.
- Outside a limit
- Over the maximum file size, or a video outside the placement's length: a Facebook feed video runs 1 second to 241 minutes, so a half-second clip is outside it.
- Not for this file type
- The placement does not list the file's type, so it gets no row.
Recommended, minimum and “at least”
A recommended resolution is the size to make: Meta's ads guide asks for 1440 × 1800 for a Facebook feed image. A minimum is the size below which the placement does not take the file: 600 pixels wide for the same placement, and 750 pixels tall for a 4:5 image. Between the two, a file runs: a fit here, without the tick, its row saying it is under the recommended resolution.
Almost every spec sheet online publishes 1080 × 1350 for this placement. Both are 4:5 and both will run, but 1080 × 1350 is the minimum sensible size and 1440 × 1800 is what Meta asks for.
The third kind is “at least”. On the Facebook and Instagram carousel pages and on Facebook in-stream video, Meta gives one size, “At least 1080 × 1080 pixels”, in the list headed Design Recommendations (as of 2026-10-22), with no minimum beside it. So the checker treats it as a recommendation: a smaller file gets a note, not a failure.
The Reels tier
Reels video has the only tiered minimum in Meta's guide: “250 pixels for ads under 30 seconds; 500 pixels at 30 seconds or longer”. The checker applies the tier for the clip's length — the stricter one, and says so, when a browser cannot read the length.
TikTok's sizes
TikTok's auction in-feed page gives minimums only: 540 × 960 pixels for a vertical video (TikTok Ads Manager help, as of 2026-10-22). With no recommended resolution or ratio tolerance stated, a vertical video that clears the minimum fits.
The carousel page lists three image sizes: Vertical 720 × 1280, square 640 × 640 or horizontal 1200 × 628 pixels (TikTok does not say whether these are minimums or recommendations). A smaller image gets a note with the size TikTok gave, not a failure, and the file size line is a suggestion too — “100 KB or less per image (suggested)” — so the checker says “over the suggested file size”.
YouTube's sizes
Google's video ad specs page gives two minimums for each shape — for in-stream, “1280 × 720 pixels (720p); 640 × 480 SD is accepted, and Google says it doesn't recommend SD”. The checker takes the SD figure as the minimum and the higher one as a note, so a file between the two passes with that note. On in-stream, 16:9 — the shape Google gives “for horizontal”, with 1920 × 1080 and those minimums — is the recommended one. The others it lists, 9:16, 1:1, 4:3, 2:3 and 4:5, are accepted ratios with no size of their own (4:3 is Google's SD shape).
Where Google's pages give more than one length, the longest is the limit and the others are notes; a file past a note passes without the tick. A bumper runs up to 6 seconds, with a note under 5 seconds: Google's video ad formats page gives a 5-second minimum. A Short runs “up to 3 minutes; only the first 60 seconds play in the Shorts feed”, with notes past 60 and under 10 seconds (6–60 seconds for Video Reach campaigns, 10–60 for other campaign types). In-stream and square video lengths vary by ad type and campaign, so their rows say “Length not checked”.
In-feed is checked as its thumbnail: 1280 × 720 recommended, 1280 × 640 at least. That minimum is 2:1, Google's figure, so a thumbnail at exactly that size reads Accepted ratio. An MP4 is not matched to it.
File size and length
Meta's image placements take files up to 30 MB and its video placements up to 4 GB; TikTok's in-feed video takes up to 500 MB, and YouTube's video placements up to 256 GB. Facebook in-stream video is the one placement with two ranges, by device: 5 seconds to 15 seconds on desktop and 5 seconds to 10 minutes on mobile. A clip inside the mobile range only fits, and its row says so. A GIF's length is not read, so its duration is not checked.
Cropping an image to a placement
For an image, pick a placement under “Crop for” and drag the box, which always has the shape of that placement's frame. If your crop is at least the placement's recommended size, it downloads at that size. A smaller crop keeps its own size, never stretched; on an “at least” frame a larger one does too, unless a browser cannot safely draw it. The line under the box says which. A PNG stays a PNG; everything else downloads as a JPEG.
When a crop is not enough
A crop only removes picture. Adapt in Terrads makes an image in the sizes it offers for each platform — Meta Feed at 1440 × 1800, Meta Story / Reels at 1080 × 1920, TikTok Feed at 1080 × 1920 and YouTube Display at 1280 × 720 among them — extending the picture with AI where a crop would lose too much of it. For a video, Adapt makes a copy in each platform size you pick.