What a formula actually gives you
A copywriting formula orders the parts of a piece of copy: which point comes first, which comes last, and what has to happen in between before you ask the reader to act. It does not supply the words. Two writers using AIDA (Attention, Interest, Desire, Action) on the same brief can produce copy that reads nothing alike, because the formula sets out what each stage needs to do. What a formula reliably prevents is a writer skipping a stage, most often asking for the click before giving the reader a reason to want it.
The three formulas covered most often are AIDA, PAS (Problem, Agitate, Solution) and BAB (Before, After, Bridge). Each suits a different shape of problem, and applying the same brief to all three below shows where they overlap and where one earns its place over the others.
The brief used throughout this page
Every example below answers the same brief: a social ad for a UK invoicing app aimed at sole traders who currently invoice through a Word template or a spreadsheet, with a headline, roughly 100 words of body copy, and a single CTA (call to action, the instruction that tells the reader what to do next). The goal is a click to start a free trial.
AIDA: attention, interest, desire, action
AIDA moves the reader through four stages in order: it grabs attention, builds interest with a detail the reader recognises, turns that interest into a want, then asks for the action. It works best on a cold audience, someone who has not been thinking about invoicing software and needs a reason to start.
Applied to the brief:
- Attention: "Still invoicing from a Word template?"
- Interest: a line naming the specific pain, such as losing track of which invoice a client has actually paid
- Desire: a line on what changes: invoices numbered and VAT calculated automatically, with one screen showing who owes what
- Action: "Start your free trial"
AIDA fails on a warm audience. A retargeting ad shown to someone who has already visited the pricing page does not need attention or interest again; both stages have already happened, and repeating them reads as if the ad has not noticed the reader already knows the product. For that audience, skip straight to a specific offer and the action.
PAS: problem, agitate, solution
PAS opens on the reader's problem stated plainly, spends a line making that problem concrete, then presents the product as the solution. It suits an audience who already feels the problem but has not connected it to a fix, which describes most sole traders invoicing manually: they know the current system is a nuisance, they just have not gone looking for an alternative.
Applied to the brief:
- Problem: "You're still chasing clients to find out if they've paid."
- Agitate: a line on the actual cost, such as the half-day lost each month reconciling a spreadsheet against a bank statement
- Solution: the app shows paid and unpaid invoices on one screen, with a CTA to start the free trial
PAS fails when the agitate line overreaches. Naming a real inconvenience, lost time, an awkward conversation with a client, works. Inventing a consequence the reader has not experienced, such as implying they will fall behind on tax deadlines because of a spreadsheet, reads as a problem manufactured to fit the formula. Agitate the problem the reader actually has.
BAB: before, after, bridge
BAB paints the reader's current situation, paints the situation once the problem is solved, then names the product as the bridge between the two. It works well where the after state is easy to picture and genuinely different from the before, which makes it a natural fit for software that replaces a manual process.
Applied to the brief:
- Before: "Right now, invoicing means opening a Word document, changing the date, and hoping you remember to chase it."
- After: "Invoices go out numbered and dated automatically, and one screen shows exactly who's paid."
- Bridge: the app, with a CTA to start the free trial
BAB fails when the before state does not match the reader's actual situation. A sole trader who has already tried and rejected two invoicing apps will not recognise themselves in a before line written for someone who has never used software at all. Where the audience is likely to have some existing tool, write the before state to match what they have.
Two more worth knowing
FAB (Feature, Advantage, Benefit) is less a persuasion structure than a discipline for writing one line at a time: state the feature, state what it does, then state what that means for the reader. "Automatic invoice numbering" is the feature, "you never send a duplicate number by mistake" is the advantage, and "clients get invoices that look organised, so you get paid without a query" is the benefit. It is worth knowing because it forces the gap between a feature and a benefit into view, a distinction copy often loses under deadline pressure.
The 4 Ps (Picture, Promise, Prove, Push) work on longer-form copy such as a landing page or sales email: paint a picture of the reader's situation, promise a specific outcome, prove it with a detail or a mechanism, then push for the action. It suits copy with room to build a case, which the 100-word ad in this brief does not have.
Where all three break down
Every formula assumes the copy has room for its full sequence, and a 90-character Google Ads description or a subject line does not. Forcing four AIDA stages into a headline and one line of body copy usually means each stage gets a fragment rather than a sentence, and the copy ends up naming a problem, a benefit and an instruction all at once without properly doing any of them. Below a certain length, pick the single stage the format has room for, usually the benefit and the action, and drop the rest.
The other failure is running every piece of copy through the same formula regardless of the brief. A formula is a check that a stage has not been skipped; a page that visibly follows AIDA in the same shape every time starts to sound like a template. Choose the formula that matches the audience's awareness of the problem and the space the format gives you, then write the sentences without leaning on the formula's names for the stages.
For the close a formula sets up but does not write, see How to Write a Call to Action. For applying these structures to a specific channel, see How to Write Ad Copy: Search, Social and Display. Once you have a headline written, running it through the headline scorer checks it against separate criteria to the formula itself.