14:22See it at the size they'll see it.
Drop a thumbnail and a title. See them at true pixel size on the phone feed, desktop home, the suggested sidebar and search, in light and dark, beside other videos — before you upload. Nothing leaves your browser.
The suggested sidebar, actual size
14:22168× 94 px
Your 1280×720 export at an eighth of its width, the title at 14 px, and everything after line 2 gone. Measured by rendering, not estimated.
Preflight your thumbnail
sample-mic.png · 1280×720 · the bundled samplenothing uploaded
YouTube, light modeDesktop home
14:22
9:41
11:08
6:52Title on Desktop homeI bought every budget mic so you don't have to — 7 under $100, tested with samples hidden: measuring…
Can you read the words? Can you tell what it is? That is your call; no number here would be honest.
Measured here: size, weight, ratio, where the title is cut, what YouTube draws over, how the edges meet the page. Not measured: whether it gets the click. For that, run YouTube Studio's Test & Compare.
Drop your own thumbnail above, or start from the sample. 1280×720 is what YouTube asks for.
See where the title is cut, and what YouTube draws over.
Every number the tool reports is a measurement: the title cut is where the browser cut it, the checks are YouTube's upload specs, the surface sizes are YouTube's. The view counts and timestamps inside the previews are placeholder chrome, like the rest of YouTube's furniture. A tool that predicts your click-through rate is guessing; this one doesn't.
1Duration badge, bottom right. Whatever is under it is covered on every surface: the sample's caption is, and the tool says so.
2Watch later and queue, top right.
3Progress bar along the bottom, for anyone who has started the video.
The specs. 1280×720, 16:9, under 2 MB, a title under 100 characters; and edge contrast against both feed grounds, white and #0f0f0f.
One thumbnail on four surfaces, every check, free.
$0
- The whole tool: a thumbnail and title on all four surfaces, both themes, every check, the 168-px look
- Nothing uploaded, no account, nothing withheld
$19a month
- Playback Check, Invoice Splitter and the other subscription tools; this one stays free
- One key, pasted once per device. Cancel from a link in the email.
Predictions, privacy and limits.
Does it predict how many people will click?
No, on purpose. A predicted click-through rate is an opinion with a decimal point; you cannot check it and it cannot learn from being wrong. YouTube Studio's Test & Compare runs a real A/B test against real viewers — use that for the verdict. This tool makes sure what you send to that test is legible and intact.
Is my thumbnail uploaded?
No. The image is read into a canvas in your browser for the measurements and shown from your device's memory. Close the tab and it is gone. The only thing that ever leaves is an email address, if you type one into the subscription form.
How exact are the surfaces?
The thumbnail sizes and title sizes are YouTube's web and mobile layouts as measured in September 2026; they change a few pixels a year and this page is updated when they do. The typeface is this page's, not Roboto, so truncation can differ by a character or two. The layout dimensions are the point.
What are the overlay outlines?
Where YouTube draws its own interface over your thumbnail: the duration badge bottom-right, the watch-later and queue buttons top-right, and the red progress bar along the bottom for anyone who has started the video. Anything you put there is covered on every surface.
What are the limits?
One image up to 20 MB (YouTube's own limit is 2 MB, and the tool tells you when you are over it). PNG, JPEG, WebP or GIF. Up to three neighbour thumbnails, one candidate at a time. The whole tool is free; a side-by-side variant comparison is planned and is not sold yet.
Now check your own.
Drop the thumbnail, type the title, and look at it at 168 pixels before anyone else does.