Aspect ratio converter
Enter your video's width and height and see the exact crop or letterbox size for 9:16, 1:1, 4:5, 16:9, 3:4 and 21:9. Free, runs in your browser.
How it works
Type your video's width and height in pixels, then choose the ratio you want to post in.
“Fill (crop)” shows the largest frame of that ratio you can cut from the middle of your video and how much of the picture it throws away. “Fit” shows the full frame you would need if you keep the whole picture and add bars or a background.
Sizes are rounded to even numbers because most video encoders require them.
Questions
Which ratio should I use for TikTok, Reels and Shorts?
They are all vertical formats, shown at 9:16 (for example 1080×1920). Check each platform's current guidance before you publish.
Why does cropping lose so much of a landscape video?
A 16:9 frame cut down to 9:16 keeps only about a third of the width, so framing matters. Snipster lets you set the focus point, or fit the whole picture over a blurred background instead.
Reframe a real video in the Snipster editor
Snipster turns long videos into captioned short clips. Free to start, no card.