Flashbacks, Voice-Over, Montages: How to Format the Tricky Parts of a Professional Screenplay
Flashbacks, Voice-Over, Montages: How to Format the Tricky Parts of a Professional Screenplay
You've got the basics down. Scene headings in caps, action in the present tense, character names centered above their dialogue. The pages are flowing. Then you hit the scene that doesn't fit the template. Your protagonist remembers her childhood. A narrator comments on the action without ever appearing on screen. Two characters argue over the phone from different cities. Or you want to squeeze three months of training into thirty seconds of screen time.
This is exactly where a lot of writers start improvising, and exactly where a professional reader spots a beginner. A flashback that isn't flagged leaves the reader lost. Voice-over written like regular dialogue makes it look as if the character is standing in the room. A montage written as two pages of prose kills the read.
The good news: these special cases follow simple, widely shared conventions. In this guide you'll learn how to format the situations that come up most often (flashbacks, voice-over and off-screen dialogue, montages, intercuts and phone calls), with examples you can copy straight into your script. You'll also see how screenplay software like Slash keeps your format clean without you having to think about it.
Flashbacks and dream sequences: make the time shift obvious
The rule. A flashback is a scene set in the story's past, and the reader should know it from the scene heading, not three lines later. The most common convention is to tag the end of the slugline:
INT. GRANDPARENTS' KITCHEN - DAY (FLASHBACK)
Seven-year-old Lea watches her grandmother knead dough.
Add a time marker when it helps. If your story jumps between several periods, include the year or a reference point: "(FLASHBACK - 1998)" or "(TWENTY YEARS EARLIER)". Pick one style and stick with it for the whole script.
Coming back to the present. When the flashback ends, the next scene simply gets a normal heading. If there's any risk of confusion, add "(BACK TO PRESENT)" or "END FLASHBACK." You don't need it every time: a clear heading usually does the job on its own.
Longer flashbacks. When an entire sequence takes place in the past and moves through several locations, open it with a "BEGIN FLASHBACK" line and close it with "END FLASHBACK." Every scene inside still gets its own full heading (INT./EXT., location, time of day).
Dreams and visions. Same logic: "INT. HOSPITAL CORRIDOR - NIGHT (DREAM)". If the surprise matters and the audience shouldn't know it's a dream, you can write the scene straight and reveal the wake-up in the action. Just never let the reader feel cheated: one short line of clarification is enough.
The mistake to avoid. Overusing them. Readers will happily accept one or two well-placed flashbacks. Ten of them suggest the present-day story isn't strong enough to carry the film. Before you write one, ask whether that information could come through an action or a line of dialogue in the present.
Voice-over vs. off-screen: V.O. or O.S.?
Two different situations. These two get mixed up constantly, but the distinction is simple:
- Voice-over (V.O.): the character is not physically present in the scene. Think narrator, inner monologue, a recorded message, a memory.
- Off screen (O.S.): the character is in the location, we just don't see them. They're talking from the next room, behind a door, or behind the camera.
You'll sometimes see "O.C." (off camera) in older scripts and TV. Whatever you choose, be consistent.
Where the extension goes. It sits right after the character's name, on the same line, in parentheses:
LEA (V.O.)
That morning, I had no idea the workshop was about to close.
Tom knocks on the bathroom door.
LEA (O.S.)
Two minutes!
Don't confuse it with a parenthetical. The parenthetical under the character name is for tone or a small piece of business: "(quietly)", "(not looking at him)". V.O. and O.S. never go there; they always sit next to the name.
Keep narration earning its place. Voice-over is powerful, but it's tempting to have it describe what the picture already shows. Save it for what the image can't say: hindsight, irony, a gap between what a character says and what they do.
In Slash, you just type the extension after the character name. The block stays formatted as a character cue (caps, standard indent) and the dialogue below falls into place automatically.
Montages, intercuts and phone calls: practical tips
The montage. To compress time (a training arc, a renovation, a relationship taking shape) you don't write a full scene for every shot. Open the montage, list short beats, then close it:
MONTAGE - LEA TAKES OVER THE WORKSHOP
-- Lea sands an old table, covered in sawdust.
-- She turns down a quote on the phone, hangs up, tries again.
-- Tom leaves a coffee on the doorstep and walks off without coming in.
-- First order delivered. The customer smiles.
END MONTAGE
Each beat should fit on a line or two. If one of them needs real dialogue, that's usually a sign it deserves its own scene. A related device, the "SERIES OF SHOTS," works the same way but covers a short, continuous stretch of action rather than a long passage of time.
The intercut. When two simultaneous actions cut back and forth (a chase, two characters the night before a big audition), establish each location once with a full heading, then write "INTERCUT - LEA'S APARTMENT / TOM'S OFFICE." From there you can jump between the two without repeating sluglines.
Phone calls. The most common use of the intercut. You have three options:
- We only hear one side: the other person isn't shown, and you just write the first character's lines as usual.
- We hear the other person without seeing them: their lines are tagged "(V.O.)", since they aren't in the scene's location. Some writers use "(ON PHONE)" or "(FILTERED)" instead.
- We see both: establish both locations, add the INTERCUT line, then write the conversation as one continuous exchange.
Transitions. "CUT TO:", "FADE OUT.", "DISSOLVE TO:" are right-aligned. Use them sparingly: a new scene heading already implies a cut. Save them for deliberate effects. Slash has a dedicated transition block that aligns itself correctly, no manual tabbing required.
Which tool handles this best? A regular word processor makes you manage every indent by hand, and the errors pile up with each rewrite. Final Draft handles all of this well, but you pay before you write a page. An online screenplay editor like Slash applies professional format as you type, is free to start, and lets you leave notes on your formatting choices before you export a clean PDF.
Conclusion
The special cases are where a script quietly reveals how experienced its writer is. A busy reader will forgive a scene that runs long. They're less forgiving of voice-over they mistake for dialogue, or a flashback they only discover halfway down the page.
Here's the short version: flag flashbacks in the scene heading, put V.O. or O.S. right after the character name, open and close your montages clearly, and use intercuts for simultaneous action and phone calls. Above all, pick a convention and stick to it from FADE IN to FADE OUT.
The rest is your software's job. Slash formats your pages to professional standard automatically, handling scene headings, character cues, parentheticals and transitions, so you can stay focused on the story.
Try Slash for free at slash-studios.com and write your next flashback without a second thought about formatting.
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