How to Write Facebook and Google Ad Copy with AI (2026 Guide)

Difficulty

Beginner

Time required

1 hour

Tools needed

• ChatGPT
• Claude or Gemini (free tier is fine)
• Google Ads account
• Meta Ads Manager
• A spreadsheet

Writing ad copy is mostly a volume problem. Google wants up to 15 headlines per search ad. Meta rewards you for testing several angles. And each line has to squeeze a real reason to click into a couple dozen characters. That's exactly the kind of job an AI chatbot is good at: churning out dozens of variations fast, trimming them to length and rephrasing the same idea five different ways.

What it's bad at is knowing what's true about your business. Left alone, a chatbot will happily promise "#1 rated service" or "results in 24 hours" because those phrases are all over the ads it learned from. That's how you end up with a disapproved ad, or worse, a misleading one.

So here's the short answer: you supply the offer, the audience and the proof; the AI generates volume; you check every line against the character limits and the ad policies; then the platforms' own testing tools tell you which lines actually work. The eight steps below walk through that loop with copy-paste prompts for both Meta ads (Facebook and Instagram) and Google responsive search ads. Plan on about an hour the first time.

Before you start: what you need

Any major chatbot works for this. ChatGPT, Claude and Gemini all handle short-form copy well, and the free tiers are enough. If you're weighing them up, our ChatGPT vs Claude vs Gemini comparison covers the differences. You'll also want a spreadsheet, because ad copy lives much more happily in rows than in a chat window.

If you're newer to prompting, skim our guide on how to write better prompts first. The single biggest lesson applies here too: the more specific context you give, the less generic the output.

Character limits at a glance

These are the numbers your prompts need to respect. Google's are hard limits; Meta's are recommendations for how much text displays well.

Google's limits come from its responsive search ads help page, which also notes that each character in double-width languages like Chinese, Japanese and Korean counts as two. Meta's figures come from the Facebook Feed image spec in its Ads Guide, where they're listed as "text recommendations." Meta's recommendations change by placement (Reels, Stories and Marketplace each have their own), so check the Ads Guide page for any placement you're buying. Going over a Meta recommendation generally means your text gets cut off with a "See more," not that the ad is rejected.

1. 1

   Step 1: Define your offer, audience and angle

   Before you open a chatbot, write three things down in plain language:

   • Offer: what exactly are you selling, at what price, and is there a deal? "Mobile dog grooming, full groom from $85" beats "pet services."
   • Audience: who's most likely to buy, and what's bugging them right now? Think situations, not demographics.
   • Angle: the one reason this person should pick you. Convenience, price, quality, speed, trust, or a specific pain you remove.

   You'll test several angles later, but start by listing three to five. Each angle becomes its own batch of copy, which makes your test results much easier to read.

2. 2

   Step 2: Gather proof you actually have

   This is the step that keeps your ads honest, and it's the one people skip. Collect the real, checkable material the AI is allowed to use:

   • Your actual star rating and review count (and where they're from, such as Google or Yelp)
   • Two or three short quotes from real reviews, with the customer's permission if you'll quote them directly
   • Concrete numbers: years in business, prices, delivery times, guarantees you really honor
   • Certifications, awards or memberships you can prove

   Paste this into a note labeled "Proof I can use." Anything not on that list is off limits. That matters for policy reasons too: Google's Misrepresentation policy prohibits "inaccurate claims or claims that entice the user with an improbable result (even if this result is possible) as the likely outcome."

3. 3

   Step 3: Generate Meta ad variations

   Now open your chatbot. This prompt gives it the brief, the proof and the constraints in one go, and asks for output you can paste straight into a spreadsheet.

   You're a direct-response copywriter writing Facebook and Instagram ads
   for a small business. Write in plain, conversational American English.
   
   Business: [WHAT YOU SELL, WHERE, PRICE]
   Audience: [WHO BUYS AND THE SITUATION THEY'RE IN]
   Angle for this batch: [ONE ANGLE, E.G. CONVENIENCE]
   Proof you may use (use ONLY these facts, never invent others):
   [PASTE YOUR PROOF LIST]
   
   Write 8 ad variations. For each, give:
   - Primary text: 50-150 characters. Open with the problem or the payoff,
     not the business name.
   - Headline: 27 characters or fewer.
   - Description: 25 characters or fewer (optional, may be hidden).
   
   Rules:
   - Do not assert or imply personal attributes of the reader (age, health,
     finances, religion, etc.). No "Are you...?" questions about the reader.
   - No superlatives like "best" or "#1" unless they are in the proof list.
   - No fake urgency, no ALL CAPS, no emoji strings.
   - Show the character count after every line.
   
   Output as a table with columns: #, Primary text, Headline, Description,
   Char counts.

   Chatbots are notoriously unreliable at counting characters, so treat those counts as a first pass. Paste the table into your spreadsheet and use a LEN() formula to check each cell. Anything over the limit goes back to the AI with "Shorten rows 3 and 6 to fit, keep the meaning."

   Run the prompt again for each angle. Three angles times eight variations gives you 24 options, and you'll probably keep six to ten.

4. 4

   Step 4: Generate Google responsive search ad assets

   Google search ads work differently. You don't write finished ads; you write a pool of headlines and descriptions, and Google mixes them. That means every headline has to make sense next to any other headline. Google's own advice is to "focus on providing as many unique headlines as you can" and to "include at least one of your keywords in your headlines" (Google Ads Help).

   You're a Google Ads specialist writing a responsive search ad.
   
   Business: [WHAT YOU SELL, WHERE, PRICE]
   Main keywords for this ad group: [3-5 KEYWORDS PEOPLE SEARCH]
   Proof you may use (use ONLY these facts):
   [PASTE YOUR PROOF LIST]
   
   Write:
   - 15 headlines, each 30 characters or fewer (count spaces).
     - 3-4 that include a main keyword
     - 3-4 about benefits
     - 2-3 using proof (ratings, years, prices)
     - 2-3 calls to action
     - 1-2 about what makes this business different
   - 4 descriptions, each 90 characters or fewer, each able to stand alone.
   - 2 display path fields, each 15 characters or fewer.
   
   Rules:
   - Every headline must make sense next to any other headline, in any order.
   - No two headlines should say the same thing in different words.
   - Standard capitalization and punctuation only. No exclamation marks in
     headlines, no repeated words for emphasis, no ALL CAPS.
   - Show the character count for each line.

   That rules section maps to Google's Editorial policy, which disallows capitalization or punctuation "that isn't used correctly or for its intended purpose" and "non-standard, gimmicky, or unnecessary repetition of names, words, or phrases."

   If a specific line must always appear, such as a legal disclaimer or your brand name, Google lets you pin headlines and descriptions to specific positions. Use pinning sparingly, though. Every pin reduces the combinations Google can test.

5. 5

   Step 5: Check every line against the ad policies

   Now review the shortlist yourself, line by line. AI output tends to fail in predictable ways, so here's what to look for.

   Meta's personal attributes rule. Meta's policy says ads "must not contain content that asserts or implies personal attributes," covering things like race, religion, age, health, disability, financial status and criminal record (Meta Transparency Center). Meta's own examples of prohibited text include "Are you Christian?", "Do you have diabetes?" and "Are you bankrupt?" Its allowed examples describe the product instead: "Bulimia counseling available" or "Meet seniors."

   The fix is almost always to talk about your service, not about the reader:

   Likely to be rejected	Safer rewrite
   Are you over 60? Our yoga class is for you.	Gentle yoga classes designed for older adults
   Struggling with debt? We can help.	Free debt consultation with a certified advisor
   Do you have back pain?	Physical therapy for back pain, same-week visits

   Google's misrepresentation rules. Cut anything that implies a result you can't back up, hides costs, or suggests an endorsement you don't have. "Lose 10 pounds this week" is the classic example of an improbable result presented as the likely outcome.

   Your own proof list. Check every number and claim against the list from Step 2. If the AI wrote "trusted by 1,000 families" and you've never counted, delete it.

6. 6

   Step 6: Try the platforms' built-in AI, with guardrails

   Both Google and Meta now generate ad text for you. They're useful, but they write from your landing page and existing ads, so they inherit any exaggeration already on your site.

   Google: AI Max and text customization. In Search campaigns, text customization is a setting within AI Max for Search campaigns that generates additional headlines and descriptions from your domain, landing pages, existing ads and keywords (Google Ads Help). Google says these generated assets only serve when they're predicted to perform better than the ones you uploaded, and it notes that starting in September 2026, campaigns using text customization are automatically upgraded to AI Max. Performance Max has the same idea, also called text customization (formerly "automatically created assets"), and it's on by default. You can see those assets marked as "Automatically created" in reporting and remove individual ones (Google Ads Help).

   If you turn either on, also set up text guidelines, currently an experimental beta for Performance Max and for Search campaigns using AI Max. You can add up to 25 term exclusions (words the AI must never use) and up to 40 messaging restrictions (concepts or styles to avoid) per campaign (Google Ads Help). Put your banned claims in there: "cheapest," "guaranteed," competitor names, whatever doesn't apply to you.

   Meta: text generation in Advantage+ creative. In Ads Manager, Meta can generate variations of your primary text and headline, and its help center describes options to tailor them by brand tone and to translate them (Meta Business Help Center). AI-generated enhancements are labeled in Ads Manager, and you can preview samples before publishing. Always open that preview. You're still responsible for what runs under your name.

   Our take for beginners: write your own core set first using Steps 3 and 4, launch it, and add the platform AI once you have a baseline to compare against. Otherwise you won't know whether the AI helped.

7. 7

   Step 7: Set up clean A/B tests

   Generating 40 variations is pointless if you can't tell which ones worked. Keep tests simple:

   • Test one variable at a time. Angle versus angle, or headline versus headline. Not a new headline, new image and new audience all at once.
   • On Meta, use the A/B test feature in Ads Manager, which splits your audience so the versions don't compete for the same people. Put each angle from Step 1 into its own ad.
   • On Google, a single responsive search ad already rotates your headlines and descriptions automatically. To test bigger changes, such as a whole new angle or landing page, use a custom experiment. Google's experiments share your original campaign's traffic and budget, and the cookie-based split (the recommended option) makes sure each user sees only one version (Google Ads Help).
   • Decide your success metric in advance. For most small businesses that's cost per lead or cost per sale, not click-through rate. A catchy headline that brings cheap clicks from the wrong people is a loser.
   • Give it enough data. Small budgets need longer tests. Don't call a winner after a day and 30 clicks.
8. 8

   Step 8: Feed the results back into the AI

   This is where AI earns its keep a second time. After a couple of weeks, export your results and ask the chatbot to find the pattern and write the next round.

   Here are results from my ad test. Columns: ad text, impressions, clicks,
   conversions, cost per conversion.
   
   [PASTE YOUR RESULTS TABLE]
   
   1. Which lines or angles performed best on cost per conversion? Only
      draw conclusions where the numbers are big enough to mean something,
      and tell me where they aren't.
   2. What do the winners have in common (length, angle, proof, tone)?
   3. Write 6 new variations that build on the winning pattern, using the
      same character limits and rules as before and only these facts:
      [PASTE YOUR PROOF LIST]

   Pause the clear losers, keep the winners running, and add the new variations as challengers. That loop, repeated every few weeks, is the whole system.

Example: a full ad set for a fictional business

To make this concrete, here's what the process might produce for Brightside Mobile Grooming, a made-up dog grooming van in Austin. The business, rating and prices below are invented for illustration only. The angle is convenience, and the proof list says: 4.9 stars from 312 Google reviews, full groom from $85, one groomer per dog.

Meta ad (Facebook Feed)

• Primary text (141 characters): Grooming day shouldn't mean a car ride, a crate and a three-hour wait. Our van comes to your driveway, and your dog is home in about an hour.
• Headline options (27 or fewer): "Dog grooming at your door" (25), "Full groom from $85" (19), "Rated 4.9 by 312 locals" (23)

Google responsive search ad (8 of up to 15 headlines)

Descriptions:

• Fully equipped grooming van parks at your home. Bath, cut, nails and ears from $85. (83)
• One dog at a time, one groomer per dog. Book a slot online and pick your day. (77)

Notice what's missing: no "best in Austin," no "Are you a busy dog owner?" and no numbers that aren't on the proof list. A real business would, of course, only use "Book Online in 2 Minutes" if its booking flow actually takes about that long.

Where this fits in your marketing stack

Ad copy is one slice of a bigger workload. If you're also scheduling organic posts and replying to comments, our roundup of AI tools for social media management covers tools that handle both. Selling online? The AI tools for ecommerce and Shopify stores guide pairs well with this one, since your product pages are what Google's AI reads when it writes your ads. And for the full picture of where AI saves a small team the most time, start with our pillar guide to the best AI tools for small businesses.

Frequently asked questions

Is it allowed to use AI-written ad copy on Facebook and Google?

Yes. Neither platform bans AI-written text, and both offer their own AI text tools. What matters is the content: AI-written copy is held to the same ad policies as anything you write yourself, and you're responsible for claims it makes.

How many characters can a Google Ads headline have?

Responsive search ad headlines can be up to 30 characters and descriptions up to 90, with up to 15 headlines and 4 descriptions per ad, as of September 2026. Double-width characters (Chinese, Japanese, Korean) count as two.

What is the character limit for Facebook ad text?

Meta publishes recommendations rather than hard caps, and they vary by placement. For Facebook Feed image ads, it recommends 50 to 150 characters of primary text and a 27-character headline. Longer text usually gets truncated behind "See more."

Why did Meta reject my ad for "personal attributes"?

Usually because the copy asserts or implies something about the reader, like their age, health or finances, often in a "Are you...?" or "Do you have...?" question. Rewrite it to describe your service instead, for example "Physical therapy for back pain" rather than "Do you have back pain?"

Which AI is best for writing ad copy?

For short ad copy, the difference between ChatGPT, Claude and Gemini is smaller than the difference a good brief makes. Pick the one you already use. Dedicated marketing tools add brand voice settings and team workflows; see our AI writing tools pillar if you need those.