What Are the Dimensions of a PowerPoint Slide? 

It’s likely that you’ve never even thought about the dimensions of a PowerPoint slide before, at least not until this very moment. After all, why else would you be here? But if you’ve ever had your slides look weird on a big screen or printed out with giant margins, chances are it was a slide size problem. 

So, what are the dimensions of a PowerPoint slide? There are basically two main options: 4:3 and 16:9.  

Wait, what even are those numbers? Aspect Ratio Explained 

Ok, let’s take a step back. We realize those numbers might no make sense to everyone. After all, what kind of number has a colon in it. The numbers above relate to aspect ratio rather than the number of pixels for length or width. Basically, aspect ratio is the ratio of width to height rather than the actual length (or width). Therefore, a slide or image that is 640×480 has the same aspect ratio as something that is 960×720.  

4:3 is that old-school, almost square shape you probably remember from your teacher’s projector back in elementary school or the old TV your parents still have in their basement. Put simply, it’s much more “boxy” than the typical computer or projector screens these days. 

16:9 is the widescreen format. It’s the one that probably looks like your current TV or your laptop screen. Basically, it’s wider and feels more modern. 

If you pick the wrong one, your slides might show up with black bars on the sides or stretched out like a funhouse mirror. Or you’ll go to print them and they’ll look like they’re floating in the middle of the page with giant white borders. Fun times. 

When should you use 16:9? 

Almost always. Seriously. 

Most projectors, big screens and laptops all expect 16:9 now. It has become the norm. If you’re presenting on Zoom or Teams or any kind of online thing, that’s also what those platforms are generally set up for. 

And if you’re turning your slides into a video? 16:9 is the way to go. 

When should you use 4:3? 

If you’re dealing with old equipment, 4:3 might work better. Now, when we say old school, we aren’t talking about equipment that is a few years old. We’re talking about equipment that you maybe haven’t seen for a decade or more. Like, actual old-school projectors or really old conference setups.  

There is one really big exception, though. If you’re mostly going to print your slides (like training packets), 4:3 can fit better on standard paper. Keep that in mind. 

[More from Twistly: How to Edit Footers in Your PowerPoint Presentation] 

Can you change PowerPoint slide dimensions after you’ve started? 

If you’ve already started building out a PowerPoint and are wondering if you can change dimensions part of the way through… that’s a tough question to answer. The technical answer is, yes, you absolutely can. But you have to ask yourself… do you really want to? 

It’ll move your text boxes around, images will shift, sometimes stuff gets squished or disappears altogether. It’s like moving all your furniture into a new house with totally different room shapes. You’ll spend hours rearranging everything. 

You’re much better off picking a size before you start designing slides. If it’s too late for that, just keep in mind what you’re getting into if you change dimensions after the fact. 

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PowerPoint Slide Dimensions: Using 4:3 vs 16:9 

We realize that’s a lot to consider so let’s break it down simply for you. Here is when you should use 16:9 and when you should use 4:3. Spoiler alert… 16:9 is going to be the preferred option in most instances. 

Presentation Type	Best Aspect Ratio	Why?
Online meetings & webinars	16:9	Most video platforms and screen shares use widescreen. No black bars, fits perfectly.
In-person events (modern venues)	16:9	Newer projectors and large TVs are all widescreen. Looks modern and fills the screen.
Conference room presentations	16:9	Almost all conference room screens and displays expect 16:9.
Big stage/keynote presentations	16:9	Allows for big visuals and cinematic feel on large screens.
Classroom or older projectors	4:3	Many schools and old venues still use 4:3 projectors; avoids stretched slides.
Printed handouts or training manuals	4:3	Fits better on standard 8.5×11 paper; no weird margins or empty spaces.
Internal office training slides	4:3 or 16:9	Depends on the equipment, but 4:3 is easier for printouts if handed out later.
Video presentations (to upload to YouTube or share as a recording)	16:9	Matches standard video format, no cropping needed.
Investor or sales pitch decks	16:9	Modern, professional look; works better if emailed as a PDF or shown on laptops.
Old community centers or legacy meeting rooms	4:3	Some older facilities still have only 4:3 options; safer to confirm first.

How to Change Slide Dimensions in PowerPoint 

The default slide size in PowerPoint is widescreen, or 16:9, so you won’t often have to change the slide dimensions. If you do, however, here is how it’s done. 

1. Select the Design tab 

2. Select Slide Size on the far right of the toolbar 

3. Select your desired size 

Don’t be confused by the term “standard” size. In this context, standard refers to 4:3, but it is not the default size. You can also opt for a custom slide size, but this is really onl necessary in very particular circumstances. 

Slide size maybe doesn’t sound like a big deal, but it saves you a ton of pain if you just pick it right at the start. If you’re unsure, 16:9 is almost always a safe choice these days. But if you know you’re printing or using a dusty old projector from 1998, go for 4:3. Either way, decide first. Your future self will thank you.