How to Write ChatGPT Ad Body Copy That Converts

A ChatGPT chat card has three text elements: a headline (3 to 50 characters), a body (up to about 100 characters) and the landing URL. The headline grabs attention. The body line has one job: give the reader enough reason to click.

One hundred characters is not much. This sentence is 76 characters. You do not have room for a brand story or a feature list. You have room for one idea that either earns the click or loses it.

This guide covers what the body line needs to do, formulas that work, examples across categories, common mistakes and how to test your way to better results.

What the body line needs to do

When someone sees your ad in ChatGPT, they have just received an answer to a question. Your ad appears below that answer. The headline caught their eye. Now the body line has to answer one implicit question: why should I stop what I am doing and click this?

The body line should accomplish at least one of these:

1. Add a proof point. A specific number, a credible claim, a detail that makes the headline believable.
2. Address a likely objection. If the headline promises something, the body can preempt the "but what about..." thought.
3. Extend the promise. Add a second benefit that makes the offer stronger.
4. Create curiosity. Hint at something the reader needs to click to learn.

Notice what is not on that list: repeating the headline, listing every feature, or adding generic praise. The body line is not a summary. It is a second argument.

Formulas for ChatGPT ad body copy

These are not rules. They are starting points. Adapt them to your product and test the results.

Formula 1: Proof + Detail

Lead with the evidence that makes the headline believable, then add a concrete detail.

Structure: [Specific proof] + [Relevant detail]

Examples:

• Headline: Slow Down a Dog Who Gulps Every Meal
• Body: Maze-style bowl that stretches mealtime to 5+ minutes. Dishwasher safe, non-slip base. (86 characters)

• Headline: 20-Degree Bag for Shoulder Season
• Body: 650-fill down, draft collar, and a zipper that doesn't snag. Packs to 8 liters. (79 characters)

The "5+ minutes" and "650-fill" are proof. The "dishwasher safe" and "packs to 8 liters" are details that answer secondary questions.

Formula 2: Objection + Answer

Anticipate the most common reason someone might hesitate and address it directly.

Structure: [Acknowledge objection] + [Counter it]

Examples:

• Headline: Subscription Snacks for Busy Families
• Body: Skip or cancel anytime. No commitment, no penalty. Ships free. (62 characters)

• Headline: Learn Spanish in 15 Minutes a Day
• Body: Not a classroom. Bite-sized lessons that fit between meetings. Free trial. (75 characters)

The first example addresses subscription anxiety. The second addresses time and format objections.

Formula 3: Benefit + Benefit

Stack two distinct benefits that appeal to different parts of the decision.

Structure: [Primary benefit] + [Secondary benefit]

Examples:

• Headline: Rain Jacket That Breathes on Uphills
• Body: 3-layer waterproof shell with pit zips and a helmet-compatible hood. 11 oz. (76 characters)

• Headline: Eye Cream That Works While You Sleep
• Body: Visibly reduces puffiness by morning. Fragrance-free, safe for sensitive skin. (79 characters)

The jacket appeals to performance and weight. The eye cream appeals to efficacy and safety.

Formula 4: Specificity + Differentiation

Name a specific detail that sets you apart from the obvious alternatives.

Structure: [Specific detail] + [What makes it different]

Examples:

• Headline: Accounting Software for Freelancers
• Body: Built for 1099 income, not enterprise teams. See all your clients in one view. (79 characters)

• Headline: Protein Bars Without the Chalky Taste
• Body: Real cookie dough flavor, 21g protein, 4g sugar. Not another brick. (68 characters)

The accounting software distinguishes itself from enterprise tools. The protein bar distinguishes itself from competitors known for bad texture.

Formula 5: Curiosity Gap

Hint at something the reader needs to click to learn. Use carefully and honestly.

Structure: [Intriguing statement] + [Reason to click]

Examples:

• Headline: The Skincare Step Most People Skip
• Body: It takes 30 seconds and changes everything else you apply. See why. (67 characters)

• Headline: Why Your Ads Stop Working After 2 Weeks
• Body: It's not your audience. It's a pattern every ad follows. Free guide explains. (78 characters)

Curiosity works when you deliver on the promise. If the landing page does not answer the curiosity, bounce rates will punish you.

Body copy by category

Different product types have different proof points. Here are examples across common categories.

Ecommerce / physical products

Focus on tangible details: materials, dimensions, weight, ratings, warranty, shipping.

• Organic cotton, double-stitched seams, machine washable. Free returns. (71 characters)
• Solid maple construction with a 10-year warranty. Ships fully assembled. (73 characters)
• Fits in your pocket, charges your phone twice. USB-C, 30-day guarantee. (71 characters)

SaaS / software

Focus on speed, simplicity, compatibility, trial or pricing clarity.

• Connects to Shopify in 2 clicks. See all your data in one dashboard. (68 characters)
• No credit card to start. Import your existing data in 5 minutes. (64 characters)
• Works inside Gmail. No new app to learn, no extra tab to check. (63 characters)

Services

Focus on process, speed, credentials or risk removal.

• Licensed therapists, not chatbots. First session within 48 hours. (65 characters)
• We handle the paperwork. You get your refund. Fixed fee, no surprises. (70 characters)
• Background-checked cleaners, same-day booking, satisfaction guarantee. (71 characters)

Education / courses

Focus on format, time commitment, credentials or outcomes.

• Video lessons under 10 minutes. Learn during your commute. (58 characters)
• Certificate from a recognized institution. Self-paced, lifetime access. (71 characters)
• Real projects, not lectures. Build a portfolio employers recognize. (67 characters)

Supplements / wellness

Focus on ingredients and format. Avoid health claims you cannot substantiate.

• Vitamin D3 + K2 in one capsule. Third-party tested for purity. (62 characters)
• Caffeine-free focus blend with lion's mane and bacopa. 60 capsules. (67 characters)
• Probiotic gummies with 10 billion CFU. Shelf-stable, no refrigeration. (70 characters)

Notice what these avoid: "clinically proven," "guaranteed results," "cures X." OpenAI restricts health claims, and making promises you cannot back is a policy risk and a trust risk.

Common body copy mistakes

Mistake 1: Repeating the headline

If your headline says "Fast-Drying Travel Towel" and your body says "A travel towel that dries fast," you have wasted half your real estate. The body should add information, not echo it.

Mistake 2: Feature dumping

You have 100 characters. Listing four features in a rush does not help anyone. "Lightweight, durable, waterproof, breathable, packable" reads like a spec sheet, not a reason to click. Pick the one or two that matter most to the question your ad answers.

Mistake 3: Generic praise

"The best choice for smart shoppers" says nothing. "Award-winning quality" says nothing unless you name the award. If you would not say it in a conversation, do not put it in your ad.

Mistake 4: Unsubstantiated claims

"Proven to boost energy" is a claim you probably cannot prove. "Contains 200mg of caffeine per serving" is a fact. In ChatGPT ads, unsubstantiated claims can get your ad rejected, and even if they do not, skeptical readers will not believe them anyway.

Mistake 5: Forgetting the click

The body line should make someone want to click. If it fully answers every question, there is no reason to visit the page. Leave something for the landing page to deliver.

How to test body copy

You cannot know which body line works best until you test. Here is a simple process:

1. Write three to five variations for the same headline and context hint combination. Each variation should try a different angle: proof, objection, benefit stack, curiosity.

2. Run them with equal budget for at least one to two weeks, or until each has at least 100 clicks. Smaller samples are too noisy.

3. Compare CTR first, then conversion rate. A high CTR with low conversion may mean the body over-promises. A low CTR with high conversion may mean the body under-sells.

4. Kill the bottom performers and write new challengers. Testing is ongoing, not a one-time project.

5. Document what wins. Over time you will learn which proof points and which objection-answers work best for your audience.

The ad character counter helps you stay within limits, and the winning ad analyzer can help you break down what makes competitor ads work before you write your own.

Body copy and landing page alignment

The body line sets an expectation. The landing page must meet it. If your body says "Free trial, no credit card," the landing page better not ask for a credit card. If your body says "Ships in 24 hours," the product page should confirm that.

Mismatches hurt twice: visitors bounce because they feel misled, and ChatGPT's ad system learns that your ad leads to poor experiences, which can raise your costs or reduce delivery over time.

Run your ad and landing page through the message match checker to catch disconnects. Our guide to landing page message match explains why this matters beyond just ChatGPT ads.

Character counting and formatting

ChatGPT ad body copy allows up to about 100 characters. That number can vary slightly by character width, so aim for 85 to 95 to be safe. Punctuation counts. Spaces count.

A few formatting notes:

• No line breaks. The body is a single line.
• Avoid all caps. It looks like shouting and may trigger policy review.
• Use periods. Short sentences read better than run-on phrases.
• Numbers often work better than words. "5 minutes" is shorter and more scannable than "five minutes."

How SecondWin helps with body copy

SecondWin writes ChatGPT ads for consumer brands, and that includes the body line. It starts by reading your site to understand your product and niche. Then it finds the longest-running ads in your niche in Meta's Ad Library, since ads that survive 60+ days tend to be the ones that keep selling, and extracts the proven promise, proof and offer from each.

From there it writes original ChatGPT ads, including headlines and body copy, matched to the questions your buyers ask. It checks each ad against OpenAI's policies and its own rules before launch. Once you add SecondWin as an Admin on your OpenAI ad account, it manages the campaigns while ad spend stays billed directly to you by OpenAI.

You can run a free analysis of your site to see the buyer questions and ad concepts it would start with. Plans and details are on the pricing page. SecondWin is independent and not affiliated with OpenAI.

FAQ

How long should ChatGPT ad body copy be?

The limit is about 100 characters. Aim for 85 to 95 characters to leave a small buffer, since character-width variations can affect display. Use every character to add value, but do not pad for the sake of length. A 70-character body that says something useful beats a 95-character body stuffed with filler.

Should the body copy repeat the headline?

No. The headline already did its job. The body should add new information: proof, a detail, an objection answer or a second benefit. Repeating the headline wastes half your available space.

What proof points work best in ChatGPT ads?

Specific numbers tend to outperform vague claims. "5-minute setup" beats "quick setup." "4.8 stars from 2,000+ reviews" beats "highly rated." Third-party validation (awards, certifications, lab tests) also works well when it is real and relevant. Avoid invented statistics or claims you cannot substantiate.

Can I use emojis in ChatGPT ad body copy?

Technically you can, but use caution. Emojis can feel out of place in a conversational AI environment and may reduce credibility for some audiences. If your brand uses emojis naturally and your audience responds to them, test it. Otherwise, stick to plain text.

How often should I update my body copy?

Test continuously. A body line that works today may fatigue in a few weeks as the same audience sees it repeatedly. Rotate in new variations every few weeks and track which messages maintain performance over time. Our guide to ad creative refresh cadence covers how often to cycle creative.