What is a slug line | All things slug lines!

Films are visually pleasing, but screenplays have to create a picture in the reader’s mind. This is where slug lines come into play. A slug line has the ability to draw your attention to the key visual element of the scene. 

In this article, we explore what a slug line is, perfect examples of slug lines and much more. You’ll be writing slug lines that capture your reader’s attention in no time, let’s check it out!

What is a slug line? 

A slug line is essential to help the reader understand straight away where the action occurs. The slug line stands out as it is written in all capitals and will draw attention to the reader immediately. 

Slug lines are used in one of two ways. 

  1. For master scene heading – These are used to show whether or not the scene occurs indoors (INT.) or outdoors (EXT.), the physical location of the scene and the time of day.
  2. Or, subheadings – These are written mid-scene and are used in a variety of ways. These are primarily used to draw the attention of the reader to a specific bit of information that sets the scene for them. 

We will look at this in a lot more detail down below, where we will explore how to write them. 

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Why is it called a slug line?

Yeah, why is it called a slug line? Simply put, the origin comes from back in the day where we used “hot-metal printing”. 

This was when printers were set to type by hand in a form called a “stick”.

Later on when they used Linotype machines which turned molten lead into letters, lines sentences etc. 

This line of lead was known as the “Slug line” and this is where it originated from.

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What is a slug line used for?

Here are the different instances in screenwriting where you’ll need to write a slug line in your script. From the mast scene to the subheadings, slug lines are integral to setting the scene.

Let’s check them out. 

Master scene heading

The master scene heading is the main type of slug line when writing your film. It’s the establishing line, written in all capitals and establishes where it’s set – inside (INT.) or outside (EXT.), and sets the location and the time of the day the scene takes place. 

It’s as simple as that; the master scene slug sets the scene and draws attention to the fundamentals for the reader.


Subheading slug lines are a way for you to draw attention to your script’s specific, important element. For example, a change in location mid-scene, a specific shot, or any other important factor that changes the scene significantly that your reader must be aware of. 

This is when you will implement a slug line mid-scene and bring this change to the reader’s attention. 

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How to write a slug line

Now you understand the four ways a slug line is used in screenwriting. Now we can look at how to write a slug line for each of the following instances. 

How to write a master scene slugline

The master scene heading is responsible for starting the scene. It establishes the location and the time of day. Like all slug lines, the master scene heading is written in all caps too. 

slug line - masterscene

In the master scene, you will firstly need to clarify where it’s happening. Is it inside (INT.), outside (EXT.), or are you coming from inside to outside (INT/EXT.), or outside to inside (EXT/INT.).

Once you have chosen where it’s happening, you will need to define the specific location where the scene takes place. Is it a kitchen, a car park, even inside an industrial oven (you never know!)?

Finally, add the time of day in which the scene takes place. 


All of your master slug lines will be very similar to this example. These are the most common, but let’s look at the other types of sluglines; next up, subheaders!

How to write subheader sluglines

Subheader slug lines are used for a range of things. You can use these for a range of reasons to draw attention to important detail. This could be from a change in shot or a swift change in location mid-scene.

subheader slug line

Subheader slug lines are used for a range of things. You can use these for a range of reasons to draw attention to important detail. This could be anything from a change in location to a specific bit of detail to draw the reader’s attention. Whichever it is, the subheader slug line must follow the format in all capital letters.

An example of using a subheading is the passing of time. If the time passed within the scene is important, adding a slug line to acknowledge this is essential. 

This would look like the following:

time passing slug line

Another great example of a location change is if someone changes location within rooms of a house or an office. That way, a slug line would be used to emphasise the change in location mid-scene.

For example:

location change - slugline

What’s the difference between a subheading slug line and a master scene slug line?

The difference between the two is that the master scene starts the scene by defining whether it’s inside or outside, the location and the time of day it takes place. 

Whereas the subheading slug line draws attention to a change within the middle of a scene that has importance to the reader. 

One thing to note is that this must be kept short and succinct. The visual elements of your screenplay will be taken into consideration and built out through the storyboarding and during the production of your film.

What is a slug line used for in screenwriting?

As explained above, this is a variation of a question we’re always asked. 

The answer for this is to either start the scene confirming whether it’s inside or outside, the physical location and the time of day it takes place. 

The subheader slug lines are used to emphasise important moments in your script, for example, a change in location mid-scene. This could be the main character strolling into a new room whilst mid-scene; this will then be noted using a slug line.

Slug lines will always be stylized with full capitals. 

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Slug line examples from iconic movies

Here are a couple of sluglines in two iconic movies. These slug lines are perfect, they’re important, succinct, and most importantly, they bring attention to a critical point without overdoing it. 

Let’s check out the slug lines from Parasite and John Wick.

Parasite slug line example

A great example of a slug line used as a subheader is in the movie Parasite. This is used to show a quick location change. 

Parasite example

Parasite uses it well and allows the reader to quickly understand the quick pace of location change mid-scene without breaking stride. 

John Wick slug line example

In this John Wick example, this is used to drive the reader’s attention to an important point in the plot. The empty gun, in which they use the simple slug line “CLICK CLICK.” 

John Wick example

Slug lines in action scenes can bring attention to a key factor; they help build pace, help drive the scene, and push the scene along. 

We hope this article on slug lines was useful to you, and you enjoyed the breakdown and examples. Let us know down below in the comments, and scroll a little further for more screenwriting articles and resources. 

Happy filmmaking.

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Jay Neill

Jay Neill is the founder, owner, and managing editor of iFilmThings and believes everyone should have access to the film resources they need to plan their filmmaking project, which is why he’s dedicated iFilmThings to helping all filmmakers.

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