Useful vs. Usable

What's The Difference, and Why Does It Matter?

Are you familiar with the words useful and usable? Of course you are. What a silly question. I meant to ask, are you familiar with the difference between the two? You may have heard them used interchangeably. Even you may have used the terms interchangeably. I’d like to take a brief moment to shed some light on the difference.

First, as I write this, I’m finding myself wondering why the terms ever got conflated in the first place.

I honestly think it’s because they look and sound the same. But just like the words car and carpet look and (and sort of sound) the same, they are actually completely different. They may go hand in hand (you know, cars have carpets on the floor, right?) but they are, quite simply, two different things.

Useful...

In the context of UX and product design, the usefulness refers to how useful the product is in helping users accomplish something. People have needs, goals, and desires. Businesses provide solutions to those needs, goals, and desires. If said solutions do not help said people accomplish those things, the solution is not useful. For a mother looking to make a smoothie for her kids on a hot day (and then a margarita for herself right after that), a blender is very useful. It will help her get the job done.

Usable...

Usability refers to the ability for people to figure out how to use something - a system, a design, a machine, whatever. For that same mother about to make the smoothie, and then a margarita, we already know a blender is useful. But what happens when she can’t figure out how to use it? What if it looks like a plane cockpit? In that case, it’s unusable.

For example's sake, let's flip the table

Let’s say the same mom has a different goal - to plan a weekend getaway. And to accomplish that goal, we give her a blender. But not just any blender. One that’s so intuitive, so natural to use, that you could practically look at it and it would blend your food. Now, I don’t know about you, but I’m not sure how a blender will help her plan the trip.

“But wait! The blender is so user-friendly! So intuitive! So, just, perfect!”

Sure, it’s very usable. But it’s useless.

“But why?”

Because it doesn’t take into account the user’s goals. It doesn't help Mom plan her vacation. And that's the goal we're talking about.

If a product isn’t usable, nothing else matters

A product can be usable and utterly useless at the same time. But typically, a product cannot be unusable and useful at the same time. The path to usefulness is paved by usability. Make sure to keep it freshly paved, and have it end up somewhere worthwhile. Otherwise you'll end up with the perfect blender and no way to plan your next weekend getaway.