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Ad Copy Mobile-First Checklist
An 8-point checklist for ad copy that survives the worst-case mobile placement. Print this and pin it.
An 8-point checklist for ad copy that survives the worst-case mobile placement. Print this and keep it next to your monitor. Every ad you ship should pass all 8 points.
1. The hook lands in the first 60 characters of primary text. Anything past character 60 may not be read on Reels-class placements.
2. The headline is under 27 characters. 40 is the technical limit; 27 is the safe budget that survives the smallest active phone screens.
3. The description is under 27 characters. Same logic. Carousel descriptions clamp at 20.
4. No critical visual elements in the right 14% of the canvas on TikTok or Reels. Right-rail engagement icons cover that region.
5. No critical visual elements in the bottom 22% on TikTok or 14% on Stories/Reels. Username block, caption, and CTA strip all live there.
6. CTA copy in the creative does not compete with the platform's CTA strip. Either remove the composed CTA or place it above 80% Y.
7. Hashtags are below the See more cutoff (after character 125 on Meta Feed, after character 100 on TikTok In-Feed). Inside the visible window, hashtags eat hook space.
8. Verified in the simulator at the worst-case placement before launch. No ad ships without a 5-minute pre-launch QA pass.
8-point mobile-first checklist for ad copy
Pin this above your monitor
Spec context
| Field | Hard max | Visible before truncate | Warn at |
|---|---|---|---|
| Primary text | 125 | 90 | 80 |
| Headline | 40 | 40 | 30 |
Source: https://www.facebook.com/business/ads-guide/instagram-stories · Last verified 2026-04-15.
Mobile-first vs desktop-first
Ad copy review on desktop is the source of most production failures. Desktop preview shows your ad in a width that doesn't exist in real impressions. Always preview at mobile width — the simulator above defaults to a 390 logical pixel iPhone-class device.
FAQ
- Should I run this checklist for every ad?
- Yes. Every ad. Every time. Five minutes per ad pays for itself on the first averted clip.
- What if my creative team pushes back on the constraints?
- Show them the simulator output. The visual evidence of an obscured hero element ends the argument faster than verbal descriptions.
- Are these constraints the same in 2026 as 2025?
- Mostly. Some Reels-surface clamps tightened. The general discipline of writing for the worst-case mobile screen has not changed.
- Can I automate the checklist?
- Partially. The character-count checks (1, 2, 3) can be automated. The visual checks (4, 5, 6) require human review.