16:9 vs 4:3 Aspect Ratio: What's the Difference?

This guide follows one photo, 1600 × 1200 pixels, as it is moved into a 16:9 frame. Seeing what has to give, and by exactly how many pixels, is the quickest way to choose the right shape and avoid surprises.

What is 16:9?

16:9 means 16 units of width for every 9 units of height, or about 1.78:1. It has become the most common shape for televisions and computer monitors, which moved to it from 4:3 (by way of 16:10) in the late 2000s and early 2010s. It is also the standard shape for UHD, 4K and 8K formats. YouTube describes 16:9 as its standard aspect ratio on a computer. Common sizes include 1920 × 1080 and 1600 × 900.

What is 4:3?

4:3 means 4 units of width for every 3 of height, or about 1.33:1. It was the shape of early standard televisions and computer monitors, and PowerPoint still offers it as its "Standard" slide size alongside "Widescreen" 16:9. Common sizes include 1600 × 1200 and 1024 × 768.

Aspect ratio is only the shape. It says nothing about how many pixels an image has, so a 4:3 image can be sharper than a 16:9 one, or the other way round. If you're not sure which shape your photo is, check your image's aspect ratio.

16:9 vs 4:3: side-by-side comparison

These are examples, not the only valid sizes. Any width and height that simplify to 16:9 or 4:3 have that shape.

At the same height, a 16:9 frame is exactly one third wider than a 4:3 frame, because 16/9 ÷ 4/3 = 4/3. At the same width, a 4:3 frame is one third taller: 1600 × 1200 against 1600 × 900.

Same image, different frame

Our 1600 × 1200 photo is 4:3. To show it in a 16:9 space, the shapes have to be reconciled in one of three ways: remove part of the picture, add space around it, or squash it. Each gives a different result.

Cropping

Keep the full width and cut the height down to the 16:9 shape.

You don't have to crop from the centre. Taking more from the top or the bottom keeps whatever matters most in the picture. Either way, that content is gone from the new version, so check the edges before you crop.

Padding

Shrink the photo proportionally until it fits the frame's height, then fill the leftover width with empty space (often black or a plain colour).

Nothing is cut off and nothing is distorted: the whole original composition stays visible. The trade-off is that the picture no longer fills the frame. Bars at the sides are often called pillarboxing; bars above and below, letterboxing.

Stretching

Forcing 1600 × 1200 into 1920 × 1080 without keeping the proportions scales the width by 1.2 (1920 ÷ 1600) and the height by 0.9 (1080 ÷ 1200). Relative to its height, everything becomes 1.2 ÷ 0.9 = 4/3 times as wide. A round sun turns into an oval about 33% wider than it is tall, and faces look broad and flat.

Which aspect ratio should you choose?

Match the place where the image will be seen. For video and full-screen content on most modern TVs, monitors and YouTube on a computer, 16:9 fills the screen. For a slide deck set to PowerPoint's Standard size, use 4:3. If you need to show something in both, frame it with spare space around the subject so a crop to either shape won't cut anything important.

How to calculate dimensions without distortion

For example, a 16:9 image 1280 px wide should be 720 px tall, and a 4:3 image 1080 px tall should be 1440 px wide. If a result isn't a whole number, round to the nearest pixel. The tiny difference in shape won't be visible.

Common mistakes

• Dragging a corner without locking proportions. That stretches the image. Keep the aspect ratio locked when resizing.
• Thinking 16:9 means higher quality. Shape and pixel count are separate. A 1024 × 768 image has fewer pixels than 1600 × 900, but 1600 × 1200 has more.
• Cropping without checking the edges. Going from 4:3 to 16:9 at the same width loses a quarter of the height, which can include heads or text.
• Assuming padding is a mistake. Bars are often the right choice when the whole picture must stay visible.