Three-Act or Four-Act Structure: Which Is Best for Your Novel?


If you’ve ever taken a high school English class, you’ve probably heard of three-act structure. But despite how widely known it is, when it comes to editing a novel, three-act structure has some major weaknesses.

Feeling stuck in the middle of your novel? Break up those three acts into four and give four-act structure a try.

Spoiler alert: four-act structure is my favorite way of thinking about the arc of a story.

I explained four-act structure to a group of writers recently, and every single one of them said some version of, “Oh! That makes so much sense, and it’s giving me lots of ideas for what to do in the middle of my story.”

And in fact, when I was first introduced to this way of structuring stories, I had that same feeling—that feeling of oh, this is how that works. I can do a lot with this.

But it’s not where most writers begin. We’re most familiar with three-act structure, which has its uses—but also some significant pitfalls.

So that’s what I’m going to share with you here: a comparison of three-act and four-act structure. And I’ll give you a simple way to think about story structure that will make writing and editing your novel so much easier.

There Are Many Ways to Structure Stories

Now, you might be thinking, four acts? Why four acts?

I suspect most of us are pretty familiar with three-act story structure. That’s the typical way we’re taught to think about stories.

But it’s far from the only way to structure the acts of a story. Shakespeare plays have five acts. And there’s even a nine-act story structure.

I spent a while one December studying the structure of Hallmark Christmas movies, and those made-for-TV movies have nine acts to spread out nicely between commercial breaks.

Now, obviously, your book won’t be interrupted by commercial breaks. So you don’t need nine acts—that’s a lot!

But why four acts? Specifically, why four acts instead of the classic three acts we’re all familiar with?

Let’s start by taking a closer look at three-act structure: why it’s so common, and the ways in which it’s limited.

Why Three-Act Structure Is Our Default

Three-act structure is the default way of thinking about stories for a reason: stories have a beginning, a middle, and an end.

That’s three parts. Three acts. Three-act structure.

It’s simple, clear, straightforward, and logical. And while story structure can get really complicated, full of obscure terms and jargon, I find that the most useful structure, the kind that best helps writers edit their books, is clear and straightforward.

You want something you can understand and apply to your book. And three-act structure is perfect for that: beginning, middle, end.

So that’s a huge pro! But . . . I’m about to complicate things.

If you study stories looking for three acts, you’ll find they fall into a pretty common pattern:

The first act, the beginning, is 25% of a story.

The second act, the middle, is 50% of a story.

And the third act, the end, is 25% of a story.

One of my favorite things to do when I’m watching movies is to see if I can identify where each of these acts starts and ends. I’ve actually started guessing, “I think this is the end of the beginning hook, the end of act one.” And then I’ll pause the movie to check my work, to see how far in I am and whether we’re about 25% through.

I’m super fun to watch movies with. This is a real crowd pleaser.

But these uneven percentages—25, 50, 25—are where three-act structure starts to run into problems that make it a less useful editing tool.

The Problem With Three-Act Structure

The thing about three-act structure is that 25% of a story is a manageable amount of story to work with.

It’s not too challenging to structure the beginning 25% of a story. Your goal here is to set up the story and kick off your character’s journey.

And it’s not too challenging to structure the ending 25%. Your goal here is to pay off the climax of the story and resolve the character’s journey.

But in between the beginning and the end, you have the middle.

Your goal in the middle is to get your character from the beginning of the story to the end of the story. That’s the most vague goal of all these acts.

Worse, this act is twice as long as the other two acts. It’s 50% of the story, which is a lot of story to think about at one time.

And that means that in this three-act structure, you spend half the book without much guidance or a clear goal for what you’re trying to accomplish.

When writers think about story this way, it’s really easy to get lost in the middle. You can wander vaguely through the middle of your story for ages, getting frustrated, getting stuck, and wondering whether anything you’re writing is really going anywhere or contributing to the story in a meaningful way.

Four-Act Structure Solves That Problem

This is why I love four-act structure. In four-act structure, you divide the story into four equal parts: 25%, 25%, 25%, 25%.

Now, you have four quadrants of equal length rather than three parts of different lengths.

Already, the middle of the story just got way easier to navigate.

Better yet, now you can give each of those quadrants a specific purpose. You can get way more specific than three-act structure, where your goal in the middle is just to connect the beginning to the end.

And when each quadrant has a defined purpose, you have a workable path from the beginning to the end of your story. A path that’s detailed enough to guide you, but not so complicated as to get you lost or stuck.

If I were Goldilocks, four-act structure would be Baby Bear’s porridge: not too hot; not too cold; just right.

Every Quadrant Has a Purpose

So what actually happens in each of these four acts? What’s that specific purpose I mentioned?

Let’s walk through each one.

Act One

First up, act one, the first 25% of your story.

In the first act, we’re getting introduced to the story. We meet the characters, we establish the setting, we figure out what “normal” is before the conflict begins.

All of that is important. You want to ground your readers in your character’s ordinary world before we get fully swept up into the story.

But the most important purpose of this first act is to incite the conflict.

In the first act, probably very close to the beginning of the first act, you’ll have the inciting incident of the story.

Your character will encounter a problem or challenge that they have to deal with, something that shifts their whole trajectory. If this thing hadn’t happened, they could continue happily for ages without changing anything. But since this thing has happened, they’re going to have to spend the rest of the book dealing with it.

So in the first act, you have the character’s normal, and you have the inciting incident.

Act Two

Next up: act two, the second 25%.

In the second act of your story, things get more complicated. The problem escalates. You have a series of progressive complications, and sometimes they make things better, but sometimes they make them much worse.

Now, if I stopped right there, you might think we’re back in three-act structure. After all, that’s all the instructions you have for that massive 50% middle chunk of your book when you’re using three-act structure: make things more complicated.

Luckily, we’re not using three-act structure. We have four acts, so we have more specificity and direction.

Let’s add some nuance to our second-act goal.

By this point, your character has been thrust out of their normal world. They’re fully embroiled in the plot.

But they’re not very good at handling this new world yet. They’re reactive rather than proactive. Their information is limited, and they don’t have a full understanding of what’s going on or the stakes they’re dealing with.

They’re trying to solve the problem that was introduced in act one. But they’re trying to solve it by doing the same things they’ve always done in the past.

Your character is being challenged in more complicated ways than they were in act one. But they haven’t yet changed how they approach those challenges. They’re still holding on to their normal ways of doing things, and they’re trying to navigate this new problem using old ways of thinking.

And that brings us to act three, the third quadrant of the story.

Act Three

In act three, we have more progressive complications that escalate the problem. The end.

Just kidding. That’s how I’d describe this part of the story if we were using three-act structure. But we’re not! So here’s a closer look at what’s happening between the midpoint of the book and the start of the final act:

By this point, your character has learned that the old ways aren’t working. They’ve started to change and adopt some new ways of thinking and handling their problems.

They’ve gained key information and experience. They’re more aware of what they’re up against and what they will need to do to solve the problem.

And because of that, they’ve shifted from reactive to proactive. They’re going to get out there and handle this.

The Difference Between Acts Two and Three

I want you to notice here how different this is from act two.

It’s still a series of complications that are building towards the climax of the story. But the way your protagonist handles those complications—and sometimes even the kinds of complications themselves—are different between act two and act three.

In act two, your protagonist doesn’t fully know what’s going on. They’re holding on to past ways of solving their problems, even when those ways aren’t serving them very well. They’re reactive rather than proactive.

In act three, your protagonist has figured some things out. They have a better understanding of the challenges they’re facing.

And since the old ways of doing things didn’t work, they’re changing their tactics to try new things. They’re shifting their approach, and they’re starting to adopt some of the actions and mindset shifts that they’ll need to make in order to be successful in the climax.

But remember, we’re still only 50% to 75% of the way through the book. They haven’t reached the climax yet. And they also haven’t learned everything they’ll need in order to be successful when they do.

They understand more things. They’re thinking in some different ways. They’re trying better, more effective tactics. They’re putting their newly-developed skills into practice.

But . . . they’re still missing something crucial. They don’t have the full truth yet.

One of the hallmarks of the third quadrant is that it usually includes some kind of catastrophic failure, the kind of thing that looks impossible to recover from.

If your protagonist were fully transformed and operating at their full potential, they wouldn’t fail, right? In fact, you’ll prove that in the climax of the story: they’ll face the biggest challenge of the whole book, and they’ll triumph against it.

(Assuming, of course, that you’re aiming for a happy ending. This four-act structure still works if you’re aiming for a tragic ending; just sub in a devastating defeat in the climax.)

Anyway, if you’re planning that your story will end well, your protagonist is going to succeed in the climax.

But before they get there, they’ll need to fail—ideally, they’ll need to fail spectacularly.

And that spectacular failure happens in act three. And it happens because even though your protagonist is starting to adopt the new way of thinking and acting, they’re still missing something crucial. They don’t have the full truth yet. They’re not very good at applying it to their life yet.

And so you’ll see them grow, develop and change in ways they never did in the first half of the book . . . and still, there’s more for them to grow into before they can succeed.

And that leads us to act four, the final quadrant of the story.

Act Four

You know what’s coming in act four: the climax of the story.

The whole story has been building to a big event. This is the point where the stakes are the highest, and where your protagonist will face their biggest challenge yet.

Here, you’re paying off everything you’ve set up in the first three acts. Everything was building up to this, the most exciting scenes of the novel.

Your protagonist will finally face the antagonist. Except now, they’re facing the antagonist as their fully transformed self.

I nearly forgot to mention one of my favorite editing mantras: Stories are about change.

And in the fourth act of your story, your protagonist must prove that they have changed.

They have let go of the old, normal-world thinking that was no longer serving them. They have adopted the new way of thinking that makes success possible. They have finally understood the crucial truths they were missing throughout the entire rest of the story.

And the actions they take, the ways they approach this final climactic challenge, reflect this new, enlightened way of being.

Your protagonist has changed. And that’s what allows them to be successful.

And once they defeat the antagonist, they return to their normal world. Maybe it’s the same place they started, or maybe it’s somewhere new. Either way, we’re back in the ordinary, a place that echoes their beginning.

But things are different now. Your protagonist doesn’t go back to the person they were before. They bring their new way of thinking and acting back to their community, and their community is changed as a result.

Four-Act Structure in Four Sentences

That’s it. Four acts that give you more clarity, direction, and purpose than the well-known but vague three acts.

If I had to sum up each of the four acts, here’s how I’d describe each one:

Act 1: Your protagonist encounters a new challenge in their normal world.

Act 2: Your protagonist fails to solve that problem using their old way of thinking.

Act 3: Your protagonist understands more about the problem and approaches it in a new way, but fails. They’re making progress, but they don’t fully understand the new way of thinking yet.

Act 4: Your protagonist faces the antagonist in a high-stakes climactic event, and they triumph by taking action that demonstrates that they have fully transformed.

Or, if I were to put all this even more simply:

Act 1: The old way of thinking is working.

Act 2: The old way of thinking is not working.

Act 3: The new way of thinking is not working—yet.

Act 4: They embrace the new way of thinking, and that’s how they achieve success.

And if you’re thinking, “But wait, I thought you said this worked for tragic endings, too,” I’ve got you covered. Here’s your fourth act if you want to write a tragic ending:

Act 4: Your protagonist faces the antagonist in a high-stakes climactic event, and they are defeated because the actions they take demonstrate that they have not embraced full transformation.

In other words, they do not embrace the new way of thinking, and that’s why they are defeated.

Your Turn: Give Four-Act Structure a Try

So how about it? Have I won you over to four-act structure?

Remember, there are so many approaches to story structure. And with a few exceptions, pretty much all of them work!

The key is to find the way of thinking about story structure that is most helpful for you.

Personally, I find this four-act approach incredibly useful. So I invite you to give it a try.

Here’s what I want you to do now:

Pull out a piece of paper and a pen, a new document, the notes app on your phone, what have you.

And see if you can tell your story in four sentences.

Write one sentence for each act. Can you describe the essential purpose of each act of your story in just one sentence?

Don’t try to cheat here and write a hundred-word-long run-on sentence. Challenge yourself to write a nice, normal sentence. I’ll even give you a word limit: forty words max.

Your sentences don’t have to be perfect. This is a rough outline, a tool for you to use as a guide as you think about how your story is structured.

But the magic of this is that it will help you start imagining your story in four parts:

Act 1: The old way of thinking is working.

Act 2: The old way of thinking is not working.

Act 3: The new way of thinking is not working—yet.

Act 4: Your protagonist embraces the new way of thinking, and that’s how they achieve success.

Give it a try. There is a lot of clarity and deeper understanding of your story waiting for you on the other side of this exercise.

I’m excited to hear how this four-act structure inspires you!

Happy editing!

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