Quick answer: Facebook truncates primary text at ~125 characters, and ~80 on mobile. Lead with your strongest benefit. Keep every word deliberate. AI Copywriting with Brand Profile generates multiple on-brand variations in minutes.
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Your product description is often the only thing standing between a scroll and a click. Write it right and it builds trust. Write it wrong and your ad disappears into the feed.
Why Product Descriptions Matter in Facebook Ads
Good product copy turns views into clicks. In a crowded feed, your description is doing real work.
Limited real estate demands clarity
Facebook truncates primary text at around 125 characters. On mobile, that drops to roughly 80 visible characters. Every word needs a reason to be there.
Product descriptions build trust and differentiate from competitors
A vague description blends in. A specific one stands out. Readers trust ads that speak directly to a problem they recognize.
Benefits vs. features: what actually moves buyers
Features describe the product. Benefits describe what the buyer gets. "Waterproof up to 30 meters" is a feature. "Stays dry on any adventure" is a benefit. Benefits convert better.
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Facebook Ad Copy Structure & Character Limits
Per Meta's Business Help Center, ad copy spans three distinct text fields. Each has its own limit, and each plays a different role in your pitch.
Primary text (125 characters): where your product description hooks
This is the main copy block above the creative. Front-load your value. Aim for 80 characters or fewer to stay safe across all placements.
Headline (40 characters): the second pitch
The headline sits below the image. Keep it punchy. One clear claim. No room for qualifiers.
Description (25 characters): reinforces value
This field is small. Use it to signal a differentiator or price point. Don't just repeat the headline.
How mobile truncation changes your copy
Mobile cuts primary text fast. Test every ad on your phone before launching. If it feels cut off, your lead is too slow.
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Step-by-Step: Writing a Product Description for Your Ad
Five steps. No padding.
Step 1: Identify your top 3 product benefits (not just features)
Ask: what problem does this solve? What outcome does the buyer get? Write those answers down before touching your copy.
Step 2: Lead with the biggest benefit in the first 80 characters
Put your strongest claim up front. Most mobile users never tap "See more." Make the opening 80 characters carry the entire message.
Step 3: Use specific, sensory language (not generic adjectives)
"Premium quality" says nothing. "Soft enough to sleep in" says something. Specific language sticks. Generic language gets skipped.
Step 4: Test your copy on mobile. If it feels cut off, it probably is
Pull up your draft in Ads Manager preview. Switch to mobile view. Read it cold. Would you stop scrolling?
Step 5: Align copy with your visual creative
Don't describe what the image already shows. Your copy and creative should add up to more than either alone.
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Product Descriptions for Different Ad Formats
Format shapes copy. What works in a single image ad won't always work in a carousel.
Single image ads: short, punchy, benefit-focused
One image, one message. Keep primary text under 80 characters. Let the visual do the heavy lifting.
Carousel ads: primary text above, card-level descriptions for each product
Per Meta's design specifications for carousel ads, one primary text block sits above the full carousel. Each card gets its own headline. Use those card headlines to call out each product's top benefit.
Catalog & Advantage+ ads: letting Meta pull product data while you write the hook
Meta's Advantage+ catalog ads pull product names and prices directly from your feed. Your job is the hook. Write primary text that works across multiple products, then let Meta handle the dynamic product details.
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Common Mistakes to Avoid
Listing features without connecting to customer benefit
Every spec needs a "so what." Connect each feature to a real outcome for the buyer.
Over-explaining what the image already shows
If your visual shows the product, don't describe the product. Add new information. Give them a reason to click.
Ignoring mobile character limits (assuming desktop spacing)
Desktop previews lie. Always check mobile. Always.
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Generate Product Descriptions Faster with AI
Manual copy iteration takes hours. There's a faster way.
How AI Copywriting uses your Brand Profile for consistency
Coinis AI Copywriting pulls from your Brand Profile. Every headline, primary text, and CTA reflects your tone, audience, and positioning. No starting from scratch every time.
Generating multiple variations to test performance
Generate five versions of your primary text in one session. Different hooks, same product. Run them to find what converts.
Why an AI-first approach saves iteration time
More time testing means more data. More data means better ads. AI Copywriting compresses days of rewriting into a single session.
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Frequently Asked Questions
How many characters can I use in a Facebook ad product description?
Facebook recommends keeping primary text to 125 characters or fewer. On mobile, only around 80 characters show before truncation. The headline field is 40 characters and the description field is 25 characters. Front-load your most important message in the first 80 characters to stay safe across all placements.
Should I write different copy for mobile vs. desktop Facebook ads?
You write one set of copy, but you must test it on mobile before publishing. Mobile truncates primary text much earlier than desktop. If your key message sits past the 80-character mark, most mobile users will never see it. Always preview in mobile view in Ads Manager.
What's the difference between features and benefits in ad copy?
A feature describes what a product has or does. A benefit describes what the buyer gains. 'Stainless steel blade' is a feature. 'Stays sharp for years without sharpening' is a benefit. Benefit-driven copy connects directly to the buyer's outcome and tends to perform better.
How do Advantage+ catalog ads handle product descriptions?
Advantage+ catalog ads can automatically pull product names, prices, and other details from your product feed. You write the primary text hook that works across multiple products, and Meta inserts the relevant product data dynamically. Focus your writing on the overarching benefit or offer.