The recommended text size for vertical video ads is large enough to read at a glance on a small phone screen while scrolling, and small enough to leave room for the product, the face, or the motion that earns attention in the first place. As a starting point to test, headline text should fill a clearly visible band of the frame — think roughly 6-10% of the frame height for a one-line headline at 1080x1920 resolution — with captions and secondary text somewhat smaller but still bold enough to read without zooming in.
Why text size is one of the first specs to get right
Vertical video ads are watched on a screen the size of a hand, often while scrolling, often with sound off, and often with one eye on a notification. Text on screen has to do a lot of work: reinforce the hook, carry the offer, and help the message land even if the viewer never turns on audio. If the text is too small, it gets skipped. If it's styled thin or placed carelessly, it competes with the platform's own interface instead of supporting your message.
Getting the recommended text size for vertical video ads right is less about hitting one magic number and more about matching size to role: a headline that opens the ad needs to be bigger and bolder than a secondary line explaining a feature, and both need to be bigger than you'd guess from looking at the frame on a desktop screen.
Safe zones: where text actually gets cropped or covered
Before sizing text, know where it's allowed to live. Most vertical ad placements overlay interface elements — profile names, captions, like and share buttons, sound icons — along the top and bottom edges of the frame, and sometimes a thin strip on one side. Text placed right at the very edge risks being cropped on some devices or covered by platform UI on others.
- Keep primary text inside the middle 80% of the frame, both vertically and horizontally.
- Leave extra margin at the top (for status bars and profile info) and the bottom third (for captions, buttons, and swipe-up prompts).
- Avoid placing anything critical within roughly 100-150px of any edge at 1080x1920 as a starting point — then check on a real device.
- If the ad will also run as 4:5 or 1:1 on other placements, design text placement to survive a center crop.
Recommended text size for vertical video ads, by element
Different elements on screen have different jobs, so they need different sizes. The table below gives starting ranges to test at the common 1080x1920 vertical resolution. Treat these as a baseline, then adjust based on how your specific font, word length, and brand style read on a phone.
| Element | Role | Starting size range (height of text) | Notes |
|---|---|---|---|
| Hook headline | Grabs attention in the first 1-2 seconds | Roughly 8-12% of frame height | Short, punchy, usually 3-6 words; biggest text in the ad |
| Supporting headline / subhead | Explains the hook or introduces the product | Roughly 6-8% of frame height | One or two short lines max |
| Word-by-word captions | Carries spoken voiceover for mute viewers | Roughly 5-7% of frame height | Must stay legible even with motion behind it |
| Feature or benefit callouts | Labels a product shot or screenshot | Roughly 4-6% of frame height | Can be smaller if paired with an icon or image |
| CTA / offer text | Final push to click, swipe, or buy | Roughly 7-10% of frame height | Often paired with a button shape or highlight bar |
| Legal, disclaimer, or fine print | Compliance or terms | As small as remains legible, typically under 4% | Keep brief; don't let this crowd out the main message |
If you only remember one rule, make it this: text that matters to the sale should never be the smallest thing on screen. Fine print and secondary labels can shrink; hooks, offers, and calls to action should stay large and confident.
Font weight and contrast matter as much as size
A large font in a thin weight can be harder to read on a moving phone screen than a smaller font in a bold weight. Vertical video ads are often watched against busy backgrounds — product shots, lifestyle footage, moving text — so contrast does a lot of the readability work that size alone can't.
- Favor bold or semi-bold weights over regular or light weights for anything that has to be read quickly.
- Use a solid background bar, subtle drop shadow, or outline behind text that sits over busy footage.
- Stick to one or two typefaces per ad; mixing several styles slows down reading.
- Avoid thin script or decorative fonts for anything functional, like a price, offer, or CTA — save them for brand flourishes only.
A quick before-and-after example
Imagine an ad for a phone stand. The first cut uses a thin, light-gray headline sized small enough to fit above the product shot, plus a tiny CTA tucked in the bottom corner. On a laptop it looks clean. On a phone, scrolling, the headline disappears into the background and the CTA is easy to miss entirely.
The fix: resize the headline to fill a clear band near the top third, switch it to a bold white or near-black weight with a soft shadow, and move the CTA into a larger bar across the bottom third with a filled background. Nothing about the product or voiceover changed — only size, weight, and placement — and the ad reads clearly even muted and shrunk down to thumbnail size.
How to test your text size before you spend ad budget
Specs are a starting point, not a guarantee. The real test is whether the ad reads at normal size on an actual phone, not a preview window on a desktop monitor.
- Export the ad and watch it on your own phone at normal distance, not zoomed in.
- Watch it on mute first — if the message doesn't land without sound, increase size or contrast on the key lines.
- Hold the phone at arm's length, or have a coworker glance at it for two seconds and tell you what they remember.
- Check it small: open it as a thumbnail or preview the way it would appear in a feed, since some platforms show a scaled-down version before someone taps to expand.
- If you're running the same ad across TikTok, Reels, and Shorts, confirm the text still reads after each platform's own UI overlays are accounted for — see how to create vertical video ads for multiple platforms for how placements differ.
Common text-size mistakes in vertical video ads
- Sizing text while looking at a large monitor, then being surprised it's unreadable on a phone.
- Shrinking the CTA to make room for a long disclaimer — the offer should win that fight, not lose it.
- Using the same small size for every line instead of a size hierarchy that guides the eye from hook to offer.
- Placing text so close to the edges that it gets clipped on some aspect-ratio exports or covered by platform captions.
- Choosing a stylish but thin font for the price or promo code, the one line a viewer most needs to read clearly.
Text size works alongside other specs, not instead of them. A correctly sized headline rendered at a low resolution will still look soft; pairing size guidance with the right resolution and bitrate keeps the whole frame sharp, not just the text layer.
Where FrameNotion fits
FrameNotion builds each ad from scratch at 1080x1920, 9:16, so on-screen text is sized and placed for a vertical frame from the first draft rather than retrofitted from a square or landscape layout. Every ad also ships as 4:5, 1:1 and 16:9, so the same message is reformatted for each crop instead of forcing one text size to survive every aspect ratio by accident.
Captions come word-by-word and the full video is designed to work on mute, which is the same readability bar this guide has been describing throughout. If a headline or CTA still needs resizing or a wording tweak after the first render, FrameNotion's change requests let you adjust text and colors without rebuilding the ad from scratch. You can see finished examples, including how headlines and CTAs are sized across different product types, on the examples page, or start from a product link on the home page.
FAQ
Frequently asked questions
Does the recommended text size change between TikTok, Reels, and Shorts?+
The underlying frame is the same 9:16 vertical shape across these placements, so the same starting sizes generally work. The difference is where each platform's own interface — captions, buttons, profile info — sits on screen, which affects placement more than size. Check your ad on each platform's actual feed view, not just the raw export.
How big should the call-to-action text be compared to the headline?+
The CTA doesn't need to be larger than the hook, but it should never be noticeably smaller or an afterthought. Treat it as one of the two or three most important lines in the ad and give it enough size and contrast to be read even if someone only watches the last few seconds.
Is there a minimum readable text size for vertical video ads?+
There's no single fixed minimum, since it depends on font weight, contrast, and viewing conditions. As a rule of thumb, if a line of text looks small or hesitant on a laptop preview, it will likely be unreadable on a phone. When in doubt, size up rather than down for anything tied to the hook, offer, or CTA.
Should disclaimer or legal text follow the same sizing rules?+
Disclaimer text can be smaller than the main message, since its job is compliance rather than persuasion. Keep it brief and legible, but don't let it compete in size with the headline, benefit, or CTA — those lines need to win the viewer's attention first.
Can I fix text size after an ad is already rendered?+
It depends on the tool. Some platforms require a full re-render from scratch for any text change. With FrameNotion, text and colors can be adjusted after the first render using change requests, so you can resize or reword a headline or CTA without starting the ad over.