Slugline in Screenwriting: Scene Headings Explained

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Published: October 16, 2025 | Last Updated: December 5, 2025

On FilmDaft, we separate sluglines into three clear types:

• Master Scene Heading — The full line that starts a new scene (e.g. EXT. FOREST – NIGHT)
• Secondary Scene Heading — A more specific location inside the same scene (e.g. EXT. FOREST – CLEARING – NIGHT)
• Mini-Slug (Subheading) — A short, all-caps phrase that shifts visual focus inside a scene (e.g. RUSTLING FROM THE DENSE TREELINE)

For example, like this:

This three-tier approach helps organize your scenes while staying close to how many professionals format scripts in the real world.

How to Format a Master Scene Heading

The master scene heading (also called a scene heading) always follows this structure:

INT./EXT. LOCATION – TIME

• INT. (interior) or EXT. (exterior)
• LOCATION — a general place, like “KITCHEN” or “FOREST”
• TIME — usually “DAY” or “NIGHT”

Example:

EXT. FOREST – NIGHT

This tells us the scene takes place outside, in a forest, at night. You use a new master scene heading every time the time or location changes.

How to Write a Secondary Scene Heading

If your scene stays in the same general area but shifts to a more specific place, you can use a secondary scene heading. This still includes INT./EXT. and a time of day, but adds a sub-location.

Example:

EXT. FOREST – CLEARING – NIGHT

This keeps the scene in the same location block but tells us we’ve moved into a smaller part of it. Secondary scene headings help guide pacing and geography without breaking continuity.

How to Use Mini-Slugs (Subheadings)

A mini-slug (or subheading) is a short line in ALL CAPS that marks a visual or spatial shift inside the same scene. It doesn’t include INT./EXT. or time. Mini-slugs are often used for:

• Shifting focus to a new sound or moment
• Zooming in on an object or action
• Breaking up long scenes for clarity

Example:

RUSTLING FROM THE DENSE TREELINE

This line doesn’t start a new scene — it simply draws our attention to a sound, creating tension before returning to the main dialogue or action.

Formatting Rules & Best Practices

• All sluglines (of any type) are written in ALL CAPS
• Use one blank line above and below any heading
• Separate LOCATION and TIME with a single dash and spaces: –
• Don’t add camera angles, mood, or action to the heading; keep that in the action lines
• Only include specific times (like DAWN or MIDNIGHT) if it matters for the scene

How Sluglines Help Production

Sluglines aren’t just for writers. They help the crew plan how to shoot your script. Each master and secondary heading helps with:

• Shooting schedules: Scenes can be grouped by location and time
• Budgeting: Each location or time block affects cost
• Lighting and set prep: “DAY” or “NIGHT” tells teams what to expect
• Script breakdowns: Helps departments know what’s needed scene by scene

Special Cases and Exceptions

Some scripts call for flexible use of sluglines. Here’s how to handle edge cases:

• INT./EXT. — Use both if the scene moves between inside and outside (e.g., a moving car)
• CONTINUOUS / SAME TIME: Use these if the action flows directly from one scene to the next
• Inserts or POV: You can use mini-slugs like INSERT – PHONE SCREEN or CHARLIE’S POV – THE DOOR

Summing Up

A slugline tells us where and when something happens in your script. Most commonly, it refers to a full scene heading. But you can also use secondary headings and mini-slugs to break scenes into clear, readable beats. Keep your formatting sharp, your language simple, and your focus tight — and your script will be easier to read and shoot.