If you’ve ever made a video for the web, you’ll know that determining an exact length can be tricky. In fact, it’s often a subject of debate. Many people will point to web audiences’ shrinking attention spans and say it should never exceed 2 minutes. While others will argue that for some topics, 2 minutes barely allows you to scratch the surface. The reality is, neither camp is wrong.

When it comes to web video, there is no hard and fast rule on length. It depends on a variety of factors, most importantly having a good idea and executing it well. That said, we’ve produced many videos and have developed a few general rules and best practices around length. As my colleague Siobhan Nash likes to say, make sure it’s “long enough to sufficiently cover your subject, but short enough to keep it interesting.” This is sound advice for any type of media, especially video.

Identify the Type of Video You Are Producing

The first factor to consider when determining length is the type of video you’re producing. Whether it’s a promotional video, how-to video, product demonstration, case study, or short documentary, the length of your video will vary.

Promotional Video

Generally speaking, a purely promotional video should be on the shorter side. There’s nothing wrong with overtly promoting your company, but online audiences aren’t patient. So if you’re talking about yourself, you better make it relevant to your audience and succinct; a maximum of 30 seconds.

Tutorials, Product Overviews, and Demo Videos

On the other hand, a how-to video that shows how to solve a real-world challenge can go longer. The same is true of a product demo or overview. For both, I would shoot for a maximum of 5 minutes. For example, here’s an in-depth product overview video that runs 4:33 minutes. Yes, the video is very product focused, but it works because of its high production value and depth of detail. The video features 3D images of the product from multiple perspectives and uses motion graphics throughout. When you combine that with detailed explanations of the features and benefits, you can keep your audience engaged longer.

And if your demo or tutorial requires a lot more time, you can organize your video in chapters. If you need 30 minutes, consider 6 five-minute segments. It may require a little more planning, but by “chunking” you content, you’re much more likely to keep your audience engaged. And creating a mini video gallery on your website is an effective way to improve search optimization.

Case Studies and Short Documentary Videos

Case studies and short documentaries lend themselves to long-form content, which by Web standards could be anywhere from 5 to 12 minutes; longer if the video is really well produced. You would use these longer formats only when your story has sufficient arc and depth, or you have a lot of rich, compelling content—both in terms of visual content and subject matter.

I love the New York Time’s mini documentaries the paper calls Op Docs. One in particular is “No Ordinary Passenger,” a seven-and-a-half minute documentary about 87-year old Stan Dibben, a former World Champion Sidecar racer from the U.K. The mini documentary explores an interesting topic and Stan is a great character with an intriguing story. It also features lots of great footage. When you have all those ingredients, 7-and-a-half minutes is not long at all.

Confirm Your Video’s Goals

Closely tied to video type, your goals play an important role in how long your video should be. If you want to drive registrations for an event, you need to present a call to action to a registration page as quickly as possible. In that case, your video should be less than 30 seconds, and probably closer to 15.

But let’s say you want to demonstrate your company’s thought leadership. You could shoot a 2-minute piece featuring an employee exploring a relevant customer issue. Two minutes, give or take a little, is a good length to demonstrate domain expertise without blathering on for too long.

And as I always advise clients, you always want to leave your viewer wanting more. So while pieces of video you like may get cut in post-production, remember that a shorter video often helps you reach your goal more effectively than a long video.

Here’s a thought leadership video we produced for our client Marshall Strategy. At a little over two minutes, it’s just long enough to demonstrate enough domain expertise, but short enough that it doesn’t drag. I think the video also leaves the viewer wanting to learn more.

Pinpoint Your Video’s Audience and Context

Who are you targeting? Where will your video be viewed? And do you have control over where it will be viewed? These, too, are important factors.

Let’s start with your audience. Are you targeting time-strapped executives or mid-level managers who are responsible for finding and evaluating solutions like yours? If the former, you better keep the content very high level and high quality, and no more than 2 minutes. If it’s the latter, you have room to go into more detail.

Where your video is physically viewed should also play into your decision on length. If your video is kicking off an event, you get the benefit of a captive audience–as captive as people with smartphones and tablets, anyway. But the point being, if your audience won’t be viewing your video through a browser on computer, phone, or device, and thus be at the mercy of a mouse click, you can make your video a little longer.

Focus on Video Production Quality and Editing

You may have a great concept and script, but if you cut corners on production, even a 30-second spot can be hard to get through. Really good production and editing can make a long video feel short, while really bad production and editing can make a short video feel long. That’s why you need to consider production quality and editing when deciding how long your video should be. These days you don’t need a Hollywood budget to produce a video that’s both substantive and visually captivating.

Editing affects the tempo of the video, which is why it can influence how long or short your video feels. Lots of short cuts from different points of view will make a video feel fast, while long drawn-out shots will make it drag. Editing also allows you to assemble the most interesting shots, which is why it’s best to shoot with at least two cameras that capture different perspectives on your subject and different types of footage. With these ingredients, a skilled editor can create an interesting visual experience that strengthens your story and keeps your audience engaged.

Determining the length of your video isn’t a black-and-white decision. It comes down to a mix of general best practices and, of course, sound editorial judgment. Remember: Long enough to sufficiently cover your subject, and short enough to keep it interesting.

For a few related tips on video production, check out Why You Need to Rethink the Talking Head Video.