What is a Slugline in a Screenplay?

The lights dim, the projector hums, and the story begins with a simple instruction: INT. BEDROOM – NIGHT. Suddenly, the audience knows exactly where they are inside, at night, in a bedroom where something important is about to happen.

That single line, written in bold uppercase letters at the top of a script, is called a slugline. It may look simple, but sluglines are the backbone of screenplay formatting. They tell the director, crew, and even the reader where the action happens and when. Without them, a script would feel like a jumble of floating dialogue and random description.

In this guide, we’ll break down everything you need to know about sluglines in 2025: how to write them, when to use them, and how to make them work for your story.

A slugline (also called a scene heading) is a line in your screenplay that sets the scene. It tells us:

• INT. or EXT. → Interior or Exterior

• Location → Where the action takes place

• Time of Day → DAY, NIGHT, DAWN, DUSK
  

Example: EXT. PARK – DAY

This instantly tells the reader the scene is happening outside in a park during the day.

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• They orient readers quickly.

• They act as a map for production teams (location, lighting, scheduling).

• They make your screenplay look professional.
  

In 2025, with many scripts being auto-checked by AI readers, clean sluglines can make or break your submission.

1. INT./EXT. – Always start with inside (INT.) or outside (EXT.).

2. Location – Be clear and specific. (INT. NEW YORK APARTMENT – NIGHT is better than INT. ROOM – NIGHT.)

3. Time of Day – Keep it simple: DAY or NIGHT. Only use DAWN/DUSK if critical to mood.

Sometimes you shift locations within the same setting. Instead of writing a new master slugline, use a secondary slugline:

Master: INT. HOUSE – NIGHT
Secondary: KITCHEN

This keeps the flow clean without cluttering the page.

When a scene moves seamlessly from one area to another (like a chase), add CONTINUOUS:

EXT. STREET – NIGHT – CONTINUOUS

This shows the action picks up exactly where the last scene left off.

If time hasn’t changed between cuts, you can add SAME to the slugline:

INT. OFFICE – DAY – SAME

This makes it clear we’re still in the same timeframe.

Modern readers, especially streaming executives in 2025 prefer crisp slug lines. Avoid wordy versions like:
INT. A SMALL, CRAMPED, DIMLY LIT ROOM INSIDE AN OLD APARTMENT – LATE EVENING Better: INT. APARTMENT ROOM – NIGHT
You can describe details in the action lines below.

• Streaming scripts use faster transitions, meaning more concise sluglines.

• Global stories often use city tags (e.g., EXT. MUMBAI STREET – DAY).

• AI tools like Arc Studio Pro can now auto-suggest sluglines based on your description but you must still edit for clarity.

• Forgetting INT./EXT. at the start.

• Adding too much description in the slugline.

• Mixing sluglines with action text.

• Using vague times (like “EVENING” instead of “DAY” or “NIGHT”).

The best way to master sluglines is to read professional scripts. Check out Get Out, Parasite, or Everything Everywhere All At Once to see how sluglines guide readers seamlessly through story and space.

Sluglines are the unsung heroes of screenwriting. They don’t get applause or Oscars, but they make every page readable, professional, and cinematic. In a world where first impressions matter, your slugline is often the first thing a reader sees.

Think of them as the spotlight that illuminates your story: clear, sharp, and guiding the audience where they need to be. Master slug lines, and you’re one step closer to mastering the screenplay itself.

1. What is a slugline in a screenplay?
   A. It’s a scene heading that shows location and time.
   

2. What are the three parts of a slugline?
   A. INT./EXT., location, and time of day.
   

3. Can I write “EVENING” in a slugline?
   A. Avoid it, stick to DAY or NIGHT unless critical.
   

4. What is a secondary slugline?
   A. A mini heading within a main location, like “KITCHEN.”
   

5. What does CONTINUOUS mean?
   A. Action flows directly from the previous scene.
   

6. What does SAME mean?
   A. Time hasn’t changed since the last scene.
   

7. Do sluglines need to be in CAPS?
   A. Yes, always in uppercase.
   

8. Should sluglines include character names?
   A. No, they describe place and time, not people.
   

9. How long should a slugline be?
   A. One line keeps it short and clear.
   

10. Can AI tools write sluglines for me?
    A. Yes, but always edit them to fit your story’s intent.