Video Aspect Ratio Calculator
Find out the aspect ratio of a video and what happens when it must fit another format. Enter width and height to get the reduced ratio, its decimal value and the closest standard. Choose a target frame – 16:9, 9:16, square, 4:5, 4:3 or 21:9 – to see the size of the black bars needed to show everything, or how much would be cut off to fill the frame.
- Runs in your browser
- No sign-up
- Free to use
The ratio is reduced with the greatest common divisor; the name is the closest standard ratio.
How to use Video Aspect Ratio Calculator
- Enter the video width and height.
- Read the ratio and the closest standard.
- Choose a target frame to fit into.
- Read the bar size and crop.
Video Aspect Ratio Calculator features
Exact ratio
Reduced with the greatest common divisor.
Closest standard
Named ratios such as 16:9 or 2.39:1.
Letterbox and pillarbox
Bar size in pixels.
Crop to fill
Area kept and percentage cut.
Orientation
Landscape, portrait or square.
Private
Runs in your browser; nothing is uploaded.
When to use Video Aspect Ratio Calculator
- Posting landscape video to vertical platforms.
- Preparing films for TV and web.
- Deciding between cropping and bars.
- Checking camera or screen-recording formats.
Video Aspect Ratio Calculator FAQ
How is the ratio calculated?
Width and height are divided by their greatest common divisor: 1920 × 1080 → 16:9.
What is the difference between letterbox and pillarbox?
Letterboxing adds bars above and below a wider picture; pillarboxing adds bars at the sides of a narrower one.
Bars or crop – which is better?
Bars keep the whole picture but waste screen space; cropping fills the frame but loses edges. For vertical platforms, cropping or a blurred background is common.
Why does my phone video show an odd ratio?
Some phones record slightly unusual sizes; the closest standard shows what it was meant to be.
Is anything uploaded?
No. This is a calculator that runs in your browser.
Aspect ratios and fitting
The aspect ratio describes the shape of a picture: 16:9 is the widescreen standard for TV and the web, 9:16 its vertical counterpart for phones, 4:3 the classic television shape, and 2.39:1 the wide cinema format. A video’s resolution determines its ratio, and reducing the pixel dimensions by their greatest common divisor reveals it.
When a video is shown in a frame of a different shape, there are two choices. The whole picture can be scaled to fit, leaving bars – above and below for wider content, at the sides for narrower content. Or the picture can be scaled to fill the frame, cutting off the parts that do not fit.
The calculator computes both options for the target you choose: the frame size and bar thickness for fitting, and the visible area and percentage lost for filling. A 2.39:1 film in a 16:9 frame needs bars of about 12% of the height on each side; cropping it would lose a quarter of the width.
Knowing the numbers helps you decide before re-encoding. The Video Aspect Ratio Converter can then apply bars, cropping or a blurred background.
All calculations happen locally.