One of the freedoms that come with the modern advertising is the ability to forget about limits. With fast connections, hi-res displays, and fancy cameras, old limits on ad formats can seem quaint. Sure, your VAST ad can be 4k. Or your banner can use that really nice photo you took with your 26-megapixel camera. But it doesn’t need to.

Keeping your ads within certain limits will make them more effective. They’ll load faster, users will react better to them, and advertising partners will have an easier time integrating them. AdButler gets asked all the time about file recommendations, so we figured it was high time we put them out in an easy to read form.

The below four tables outline our recommendations for the most common ad formats. They are for the most part based on the IAB’s recommendations, which you can find here. Our recommendations are definitely a bit more general, but I like to think they’re more realistic.

How to read our recommendations

The below tables all follow a similar structure, and most of the tips can be applied to the other ad formats. For instance, try and keep your ad file size as small as possible by staying below the recommended. And, if you’re going above the max, you should be absolutely certain you need that space.

Especially if you’re working with mobile. Mobile can be extremely sensitive to advertising, and the capabilities of people’s phones can vastly differ depending on demographics.

The only other recommendation I can offer is to work within the formats. If you want something animated, use an HTML5 banner. Animated gifs work, but they’re huge and cumbersome. CSS animations, like the kind that banner creators use, or video is almost always a better avenue. Know what you’re trying to do and use the right tools.