How it works
Upload your thumbnail, type your planned title and channel name, and the tool renders your video inside realistic YouTube layouts: the desktop home grid, search results, the suggested-videos sidebar, and the mobile feed. Flip between light and dark mode to check contrast in both.
Why previewing matters
A thumbnail that looks great full-screen in your editor can fall apart at 210 pixels wide next to twenty competitors. Small text becomes unreadable, faces shrink, and low-contrast designs vanish in dark mode. Previewing in context catches these problems before you publish, not after your click-through rate tells you.
What to look for
Check that the focal point reads instantly at sidebar size, that any text is legible on mobile, that the design still pops in dark mode, and that your thumbnail doesn't blend into the surrounding videos. If your eye doesn't land on it within a second, viewers' won't either.
Frequently asked questions
What size should a YouTube thumbnail be?+
1280×720 pixels (16:9), under 2 MB, in JPG, PNG, or WebP format. YouTube scales it down everywhere it appears, which is exactly why previewing at small sizes matters.
Is my thumbnail uploaded to your server?+
No. The image is previewed entirely in your browser and never leaves your device.
Can I compare my thumbnail against other videos?+
Yes — the preview places your thumbnail in a feed surrounded by other video cards, so you can judge whether it stands out the way it will on the real home page.
Why should I check dark mode?+
A large share of YouTube viewers browse in dark mode. Thumbnails with dark backgrounds or thin dark text can lose all contrast against YouTube's dark UI, so always check both themes before publishing.
Does this show my real click-through rate?+
No tool can predict CTR exactly. This previewer helps you catch legibility and contrast problems early; for real data, publish and compare CTR in YouTube Studio or run an A/B test with YouTube's Test & Compare feature.