PowerPoint slide sizes and aspect ratios

1. What a slide size is

A PowerPoint slide size is a physical dimension, like paper, rather than a screen resolution. You set it under Design, Slide Size, in inches or centimetres. There is no box for pixels.

That is why the size you see on screen and the pixel count of an exported image are different things. On export, the pixel count is the slide's physical size multiplied by a pixel density.

2. The basic rules: three presets

Microsoft's documentation states the real dimensions. Standard (4:3) is 10 x 7.5 inches, Widescreen is 13.333 x 7.5 inches, and On-screen Show (16:9) is 10 x 5.625 inches.

One thing trips people up here. Widescreen and On-screen Show (16:9) are the same ratio at different sizes. Microsoft's documentation says widescreen gives more slide surface for content, which is why it recommends that one. Picking by ratio alone changes how large your text feels.

Standard and widescreen share a height. Both are 7.5 inches, and only the width grows from 10 to 13.333. That is why converting a 4:3 deck to 16:9 widens it rather than cropping the top and bottom.

A custom size is accepted from 1 inch up to 56 inches. PowerPoint rejects anything outside that.

3. The rules inside this page

Pick a preset and its size appears in inches, centimetres and pixels together. Type your own numbers and you get the same three units plus the ratio.

The presets are split into two groups. The top three have their dimensions stated in Microsoft's documentation. The rest are common ratios we calculated. Mixing the two would let our numbers read as official ones, so they are kept apart.

Microsoft's own written figures are shown separately too. Widescreen is given as 13.333 inches and as 33.867 centimetres, yet 13.333 times 2.54 is 33.866. The real size is 13 and one third inches, so this page calculates with that and the ratio comes out as exactly 16:9.

Converting to pixels needs a density, and that figure is not in Microsoft's documentation. The default is 96, the page says so plainly, and you can change it.

Fit to a ratio fixes one side and works out the other. A ratio with no common name is shown as a number pair rather than given an invented name.

This page never uploads or edits a file. It calculates sizes, and the actual slide size still has to be changed under PowerPoint's Design tab. Nothing you enter is sent to a server.

4. Getting it right

For a new deck, widescreen (13.333 x 7.5 inches) is the safe choice. Nearly every screen and projector is 16:9 now, and it is PowerPoint's default.

Converting an old deck to 16:9 leaves space at the sides. PowerPoint asks whether to scale the content up or leave it, and leaving it keeps your text sizes consistent.

If the slides are headed for export as images, decide the pixel density first. Use 96 for screen, 150 or 300 for print. Widescreen at 96 comes out as 1280 x 720 pixels.

5. A little deeper

For a portrait deck, swap the width and height. 7.5 x 13.333 inches is 9:16, the shape of a deck meant to be read on a phone. PowerPoint has no portrait preset, so you enter it yourself.

For something printed, A4 landscape (about 11.693 x 8.268 inches) is close. That figure comes from the paper standard rather than from PowerPoint, so this page keeps it in the calculated group.

Pixel density belongs to image export, not to the slide itself. Exporting the same slide at 96 and at 300 changes the pixel count more than threefold while the size in inches stays put.

6. Where people get stuck

If your 16:9 deck has text at a different scale from someone else's, one of you probably picked Widescreen and the other On-screen Show (16:9). Same ratio, but 13.333 inches against 10.

If you are unsure whether to type 33.87 or 33.867, pick the preset instead. Typing a rounded decimal slides the ratio very slightly off 16:9.

An out-of-range message means the value is under 1 inch or over 56. If you entered pixels, check the density first: at 96, 5,376 pixels is 56 inches.