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Guide

How to write ad copy variants with ChatGPT

Updated

To write ad copy variants with ChatGPT, give it the offer, the audience, the landing page and the platform, and ask for three to five variants that each take one angle: the pain, the outcome, proof, an objection or speed. Keep the offer, the call to action and the landing page the same in every variant, so the test tells you which angle works. Ask it to write to the platform's limits and count the characters; Google's responsive search ads take headlines of up to 30 characters and descriptions of up to 90, shown in any order. Then check every claim against proof and build a test matrix before you spend.

Short answer

  • Three to five angles, one per variant.
  • Hold constant: offer, call to action, landing page.
  • Count to the limits: Google headlines 30, descriptions 90.
  • Check claims and set a minimum before calling a winner.

The brief to copy

Ad variants brief

"Write ad variants for [product] to [audience] on [platform]. Offer: [offer]. Call to action: [CTA]. Landing page: [URL]. Keep all three the same in every variant.

Pick three to five angles from: pain, outcome, proof, objection, speed. One angle per variant; label it.

Write to the limits and show the character count: [for Google search, at least 8 headlines of up to 30 characters and 4 descriptions of up to 90; each must make sense alone].

Lead with a number, the audience's job, or the pain in their words. No 'Discover', no 'The best way to', no capitals or exclamation marks for emphasis.

Use only these facts and numbers: [paste your proof points]. Then a test matrix: variant, angle, hypothesis, the metric to judge."

A worked example

Illustration: a made-up business. A scheduling app for dental clinics tests three angles on Google search, with the offer "free for 30 days" and the same landing page throughout. From the draft, with character counts:

From the draft

Speed: "Book a Patient in 1 Minute" (26) · Proof: "Used by 640 Clinics" (19) · Pain: "Your Front Desk Stops Chasing" (29)
Also: "Scheduling for Dental Clinics" (29) · "Free for 30 Days" (16) · "Online Booking, Done Right" (26) · "Reminders Patients Answer" (25) · "Switch in an Afternoon" (22)

Descriptions: "Patients book online in under a minute. Text reminders before every visit. Try it free." (87) · "Your front desk stops chasing calls. Online booking and reminders in one app." (77) · "Used by 640 clinics. Set up in an afternoon with the calendar you already use." (78) · "Free for 30 days. Card required; cancel any time before day 30. No setup fee." (77)

The marketing lead checks each claim: "under a minute" and "640 clinics" are in the proof file; the AI's "Fewer No-Shows" headline is dropped because there's no data yet. The test matrix sets the judge as click-through rate for headlines and a minimum of 1,000 impressions and 30 clicks per variant.

Check before launch

  1. Every variant changes one angle and nothing else.
  2. Every line is within the limit, counted with spaces.
  3. Each headline makes sense alone, since they show in any order.
  4. Every number and "best" has proof; see rules for AI-written marketing claims.
  5. No customer data went into a personal AI account; see what not to paste.

Next step: keep the brief

Every campaign starts from the same brief. Marketing prompts, saved shows where to keep it with your proof points and voice, so each new test starts from them.

Skills for this

All skills

Questions

Can ChatGPT write ad copy?

Yes, if you give it the offer, the audience and the platform's limits. Ask for three to five variants, each built on one angle (the pain, the outcome, proof, an objection, speed), with the offer, call to action and landing page the same in all of them, so a test tells you which angle works.

What are the character limits for Google search ads?

Google's help says responsive search ads take up to 15 headlines of up to 30 characters and 4 descriptions of up to 90, with at least 3 headlines and 2 descriptions. Japanese, Chinese and Korean characters count as two. Headlines can show in any order, so each must make sense alone.

How long should I run an ad test?

Until each variant has enough traffic to compare. A common default is at least 1,000 impressions and 30 clicks per variant before calling a winner; if the budget can't reach that, test fewer variants.

AI skill

Have your AI write ad variants ready to test

Put this skill in AI Skill Pod and everyone on your team gets it in their Claude, Cursor or ChatGPT (Pro, Business, Enterprise): one invite link, free to start. Ad copy variants with a test matrix has your AI write each campaign's variants to your rules: three to five angles, one per variant, the offer held constant, copy counted to each platform's limits, policy traps flagged, and a test matrix with a minimum before you call a winner.

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Sources

  1. Google Ads Help: About responsive search ads — up to 15 headlines of up to 30 characters and 4 descriptions of up to 90; at least 3 headlines and 2 descriptions; 2 path fields of 15; Japanese, Chinese and Korean characters count as 2; headlines and descriptions may appear in any order (read 2026-11-05)
  2. Google Ads policy: Editorial — no capitalization, punctuation or repetition used for something other than its normal purpose (read 2026-11-04)
  3. FTC Policy Statement Regarding Advertising Substantiation — a reasonable basis for objective claims before they run (read 2026-11-05)
  4. OpenAI Help: Data controls — personal plans train on chats by default unless turned off; read through search-result text (read 2026-11-05)