Black bars on your TV: What aspect ratio actually means

Black bars along the top and bottom, or down the sides, are usually not a fault at all. They are the honest way a widescreen TV shows content that is a different shape from the screen. Sometimes, though, they come with a setting that is quietly cropping or stretching your picture. Here is the difference, and when to leave the bars well alone.

What aspect ratio actually is

Aspect ratio is simply the shape of the picture, its width set against its height. Modern TVs are 16:9, a widescreen rectangle. Old TVs and old programmes were 4:3, almost square. Cinema is wider still, often around 2.39:1, a long letterbox. Black bars appear whenever the shape of what you are watching does not match the 16:9 shape of your screen. They are the TV being honest about that mismatch, not hiding part of the picture.

Why films have bars top and bottom

Many films are shot wider than your 16:9 TV, at around 2.39:1, the classic cinema shape. To show that full width without squashing anyone, the TV fits it side to side and leaves black bars above and below. This is called letterboxing, and it is correct: You are seeing the whole frame exactly as it was composed. Zooming in to fill the bars simply throws away the top and bottom of the image, so the right move is to leave them.

Why old shows have bars down the sides

The opposite happens with old 4:3 programmes, which are nearly square. Shown properly on a wide 16:9 TV, they leave black bars to the left and right instead, which is called pillarboxing. Again this is right: The alternative is stretching a square picture sideways until everyone looks short and wide, or zooming in and cutting off the tops of heads. The side bars are what keep the shape correct.

When the bars really are a problem

Two cases are worth acting on rather than accepting:

Stretching. If faces look fat and circles look like eggs, the TV is in a Stretch or Wide mode, forcing the wrong shape to fill the screen. Set the aspect control back to Auto, Original or 16:9.
Cropping and overscan. If the bars themselves are fine but the edges of the actual picture are being cut off, that is overscan, a legacy setting that zooms in slightly and hides the outer edge. The Overscan and Screen Fit test shows whether your TV is doing it, and how to switch it off.

Questions people ask

Why does my TV have black bars at the top and bottom?

Because the film is wider than your 16:9 screen, usually shot at around 2.39:1. The bars let the TV show the full width at the correct shape. It is normal and correct, not a fault; zooming in to remove them crops off part of the picture.

How do I get rid of black bars on my TV?

For genuine film letterbox bars, you generally should not, because removing them crops the image. If you must, a Zoom or Wide mode fills the screen at the cost of the edges. If the bars come alongside a stretched, distorted picture, set the aspect ratio back to Auto or 16:9 instead of stretching.

Is 16:9 or 21:9 better for a TV?

For a normal living-room TV, 16:9 is right: It matches broadcast, streaming and gaming, and only cinema films are wider. Ultrawide 21:9 screens suit a monitor or a dedicated film room, but they put side bars on everything that is not cinema, which is most of what people watch.

If the picture edges look cut off rather than bordered, run the Overscan and Screen Fit test to see whether your TV is cropping them, and how to turn it off.