Layouts and measurements for common script formats.

Script Layout

It’s very easy to get too hung up on the detail of script layout. But equally, if you want your work to be taken seriously, it helps if it looks professional. First impressions count for a lot, and a script that looks professional will probably get treated slightly better by editors and producers. A professional layout suggests that you know what you're doing as a writer. (And beginning writers may even feel more professional when they see their work laid out like a ‘proper script’.)
The two reasons why a producer or editor likes a script in standard format are that: Standard layout also has the advantage of being ‘invisible’ to the editor — there’s nothing unusual in it to distract them from becoming absorbed in your story and characters. And in the end it’s these that really count.
The easiest way to format a script is to write it with script formatting software. These usually come with a number of standard layouts for you to use. But you can also achieve a professional appearance with an ordinary word processor — it just takes longer to get right.
A good way to learn how to lay out a script is by reading scripts. Be aware, however, that published scripts which you can buy in bookshops are often no more than ‘transcripts’. Someone has transcribed the dialogue from watching a recording of the original film or TV programme, and has added their own descriptions of the action. These are useless to you. What you need is a final author’s or director’s draft, and these are available from various suppliers. (The exact names for these drafts vary, and to explain the difference between them would mean getting into the politics of film-making. But there's usually a ‘final draft’ which includes all the final changes and rewrites, but leaves out all the camera angles.)
By reading scripts — and comparing them with a video of the film or TV programme — you can see not only how they are laid out, but also how the script writer conveyed the tone and action of the piece through stage descriptions.
From reading any script — whether for film, television, radio or stage — you can pick up the most fundamental principles:
1. The basic elements of a script are: (Other elements may also appear, such as scene headers, but not always.)
2. All three of these are typed and laid out distinctively — so it’s easy to tell them apart.
3. Actions are written in the present tense (‘Alice goes to Bill’, not ‘Alice went to Bill’).

Cole and Haag Screenplay Format

Hil Cole and Judy Haag used their experience providing script typing services for TV shows and movies to write a couple of books (see below) which have become standard reference works for scriptwriters. These go into exhaustive detail and provide pages and pages of excellent examples. The basic screenplay layout they describe is the ’standard format’ which almost any producer will be familiar with.
Two basic principles of Cole and Haag are that paper is US Letter size, and the font is Courier 10-pitch. So you need to set your word processor to use 12-point Courier or Courier New. (Note that point and pitch are different. You need 12-point, but 10-pitch.) In Europe producers are likely to accept A4 size paper; and in some cases they may expect it. These two paper sizes are close enough that similar margins and tab stops can be used with both.
If you look at a sample page, you’ll see it’s broken into lines and paragraphs. The positioning of these on the page indicates what kind of element it is:
Some of these should be avoided in the script you submit to a producer or editor. For example, scene numbers are usually only added once a script goes into production, so you don’t usually need to number your scenes. You should also avoid transitions and cue tags, as those are really a director’s decision. (But do write cue tags if a character is narrating in voice-over, otherwise the editor will think the character is speaking those words as part of the scene.) Also keep parentheticals to an absolute minimum, because they’re really an actor’s decision, not yours.
Since 12pt Courier — which is the standard font for screenplays — prints 10 characters to the inch, it makes sense to use inches (rather than centimetres) as the measure for margins and tabs, as follows:
[NOTE: I think these measurements are correct, but I'll double-check them.]
Using Cole and Haag’s layout, scripts should play at about one minute per page — so you’re looking for a total length of 100–120 pages.
There are many more conventions and fashions about screenplay format. Denny Martin Flinn’s book (see below) can help you steer a course through these.

BBC Script Formats

In Britain, the convention of using the fixed width Courier typeface for TV and radio scripts is disappearing. Many production companies now use a variable width typeface such as Arial or Times, because this makes scripts more readable to actors. Individual programmes sometimes use their own slight variations on the old formats and expect writers to use these; but unless you’ve been asked to use a specific format, I think most producers and scripts editors are likely to be happy with a ‘standard’ layout.
The following layouts are taken from recent (late 2003) advice and samples from the BBC Writers’ Room, who have made available a collection of templates for Microsoft Word. Users of other word processors and script formatters should be able to set them up using these measurements. (These are all for A4 size paper, as I’ve no idea what layouts are used in the US.)
TV sitcoms use a slightly different format:
[NOTE: I need to check these measurements for accuracy]
The radio drama format is:
The radio live-comedy format is used for radio sitcoms and sketch shows recorded in front of a live audience. It is the same as the radio drama format, with the addition of sound effects which need to be played live during the recording.

Stage Plays

I’m not aware of any standard layouts for theatre scripts. These tend to be similar to the layout used in radio drama, because it’s easy for actors to read. So the following is my own suggestion:

Setting Up Your Word Processor

Most word processors allow you to set up different page and paragraph styles. (If yours doesn’t, then you may want to investigate OpenOffice.) Try looking up ‘page’, ‘margins’, ‘paragraph’, ‘styles’ and ‘template’ in your word processor’s Help.
If you can find the Page Layout setting, this should enable you to set the page margins, using the measurements given above.
If you can find the Paragraph setting, you can set the left and right indents for each paragraph. (Remember that you will need to subtract that amount of any page margins from all the left- and right-hand paragraph measurements given above.)
Some paragraph elements continue on the same line as the previous element. For example, Dialogue continues on from Character Name in radio and stage plays. You can probably achieve this by creating a single paragraph with general left and right indents for the second (right-hand) element; then set the first-line indent to a negative distance, and create a tab stop set to the same distance. So for a radio script, you could create a Dialogue paragraph with left and right indents both set to 0"; then set a first-line indent of –2.0", and a tab stop of 2.0".
Once you’ve set up the page and paragraph styles, you can probably save it all as a ‘style sheet’ or ‘document template’ so you can re-use the same settings when you write your next script.

Useful References

Hil Cole & Judy Haag, The Complete Guide to Standard Script Formats, Part I: The Screenplay
Hil Cole & Judy Haag, The Complete Guide to Standard Script Formats, Part II: Taped Formats for Television
Denny Martin Flinn, How NOT to Write a Screenplay