I know this probably isn’t a big enough question, but I’m still curious and hoping for an answer. I’m not new to writing, but brand new to screenplays. I have no idea how to do notations. Like what INT. and EXT. mean and those sorts of things.

–Micah

INT. and EXT. stand for “interior” and “exterior.” Basically, any time the scene takes place inside a building, you use INT. the scene header. If you’re outside, you use EXT. In most cases, it’s very clear cut which one you would use. You are:

INT. LIVING ROOM – DAY

INT. OVAL OFFICE – NIGHT

INT. BARBARELLA’S SPACE SHIP – DAY

EXT. SUPERMARKET PARKING LOT – DAY

EXT. CASTLE MOAT – DAY

EXT. VULCAN DESERT – DAY

Sometimes, a situation will arise where it’s not clear which one really makes more sense. For instance, you’re clearly

EXT. ROSE BOWL – DAY

but are you INT. or EXT. for the Superdome? Or what if a character is using a phone booth? In both cases, it’s your call. Just be consistent. And for scenes that take place in a moving car, I often note it as

INT./EXT. RONNA’S CAR – NIGHT [DRIVING]

to indicate that we’re both inside and outside of the car during the scene.

In addition to INT. and. EXT., you’ll occasionally see EST. used in a header. EST. stands for “establishing” as in “Okay, now we’re at the Grand Canyon.” Personally, I never use it. By definition, an establishing scene wouldn’t have any real action or dialogue, so I find it clearer just to use EXT. followed by a single word of action: Establishing.

EXT. WHITE HOUSE – DAY

Establishing.

INT. OVAL OFFICE – DAY

The Vice President ransacks the desk drawers, finally finding a pack of gum.