What Is an App Subtitle?

The app subtitle is the second line of metadata Apple gives you on the App Store. Thirty characters, sitting right under the app name, doing two jobs at once: helping the algorithm rank your app for the right keywords, and helping the human deciding whether to tap.

For app marketers, publishers, and developers, the subtitle is one of three indexed fields on the App Store — alongside the app name and the hidden keyword field. It's also one of only two visible-to-users metadata fields, which means it doesn't just affect ranking, it affects whether someone reads your description at all. Apple introduced the subtitle with iOS 11 in September 2017, when it redesigned the App Store and added the dedicated tagline slot under the name.

It has been part of App Store Optimization (ASO) best practice ever since.

Why the App Subtitle Matters for ASO

Two reasons: keyword ranking and conversion.

The subtitle is indexed for App Store search. Apple's search algorithm reads the subtitle the same way it reads your app name and keyword field. That gives you a second 30-character window to rank for keywords your title can't fit. If your name is "Calm" and your subtitle is "Sleep & Meditation Tracker," you rank for "sleep tracker" and "meditation" without crowding the brand. Subtitle keywords carry less ranking weight than title keywords but more than keyword-field terms — and they're visible, which is why most ASO teams treat the subtitle as the highest-leverage metadata test you can run.
The subtitle drives conversion. On your product page, the subtitle is the first sentence a user reads after the icon and name. In search results, it renders right under the title in a smaller font. A vague subtitle ("The smart way to live") gets scrolled past. A specific one ("Period and ovulation tracker") gets the tap. The subtitle is one of the cleanest levers for moving conversion rate and click-through rate (CTR) from search.

App Subtitle Character Limit and Technical Rules

The subtitle field has three rules worth knowing before you write a single character.

30-character limit, counted in UTF-16 code units. That sounds technical — what it means in practice is that most letters and digits count as one, but emoji and certain CJK (Chinese, Japanese, Korean) characters can count as two. App Store Connect enforces the limit at submission, so the field will tell you when you're over.
Ships with the app version. Unlike promotional text — which you can edit any time — the subtitle is part of your app's metadata and ships with each new app version. To change the subtitle on the live default product page, you submit a new version. To test alternative subtitles without a full update, use Custom Product Pages or Product Page Optimization.
Localizable per language. You can — and should — set a different subtitle for each App Store language. The keywords that work in English aren't the keywords people search in Japanese or Brazilian Portuguese. Localized subtitles are one of the highest-ROI changes most apps haven't made yet.

App Subtitle vs. App Title, Promotional Text, and Other Metadata

The subtitle is one of five App Store metadata fields you'll touch regularly. Each does a different job. The app title carries the most ranking weight; the subtitle adds a second visible window; the keyword field is hidden but indexed; promotional text is editable any time but not indexed; the description drives conversion, not ranking.

Field	Limit	Indexed for search?	When you can edit	Localizable	What it's for
App Subtitle	30 char	Yes	Per app version	Yes	The value-prop tagline.
App Title (Name)	30 char	Yes (highest weight)	Per app version	Yes	The brand handle.
Keyword field	100 char	Yes (hidden)	Per app version	Yes	Comma-separated; never seen by users.
Promotional Text	170 char	No	Anytime	Yes	Time-sensitive announcements above the description.
Description	4,000 char	Effectively no	Per app version	Yes	First few lines drive conversion, not ranking.

On the Google Play Store, there's no direct equivalent. The closest analog is the 80-character Short Description, which is also indexed and visible under the app name. Different field, different limit, same job.

How to Write an Effective App Subtitle

Five rules. None of them complicated. Most apps still get them wrong.

Don't repeat the title. If "tracker" is in your app name, the algorithm doesn't reward you for putting "tracker" in your subtitle too. You've burned 7 characters for no extra ranking. Use the subtitle for keywords your title can't fit.
Lead with the value proposition. "Period and ovulation tracker" tells you exactly what the app does. "The smartest tracker for women" doesn't. The subtitle should answer "what does this app do for me?" — not "how do we feel about ourselves?"
Avoid Apple-disallowed language. Apple rejects subtitles that mention price ("Free!"), make ranking claims ("#1 app"), reference time ("Limited time"), or name competitors. These are the most common rejection reasons. Save those for promotional text or marketing creative — neither of which is indexed anyway.
Localize per market. Don't ship the English subtitle into ten locales. Translate, then re-keyword for what people actually search in each language. The highest-ROI subtitle changes are usually outside the home market.
Test it. The subtitle is one of the highest-leverage fields for A/B testing through Custom Product Pages or Product Page Optimization. Small changes in subtitle copy can move both ranking and conversion meaningfully.

App Subtitle Examples: Good vs. Bad

Real apps, top of the charts. The pattern is the same as titles — be specific, be clear, be human.

Good subtitle	Bad subtitle	Why
Period & Ovulation Tracker	The Smart Way for Modern Women	Specific keywords beat aspirational fluff.
Sleep & Meditation Tracker	#1 Calm App on the Store	Functional vs. ranking claim — Apple rejects ranking language.
Send, Spend, Save Money	Free Banking Finance App 2026	Value prop vs. keyword spam plus disallowed price language.
Notes, Docs, Tasks, Wikis	The Best Productivity App	Concrete features vs. vague superlative.

The good ones do two things in 30 characters: tell you what the app does, and give the algorithm one or two keywords worth indexing. That's the whole job.

Common App Subtitle Mistakes to Avoid

Duplicating title keywords. The single most common mistake. You get 30 characters; don't waste them repeating the word that's already in the name.
Stuffing keywords with no flow. "Sleep Meditation Calm Anxiety" might tick four boxes for the algorithm, but it reads like a search query, not a tagline. Apple's review team flags this.
Skipping localization. Running an English subtitle in non-English markets leaves rankings on the table in every locale outside the home market.
Treating it like promotional text. The subtitle ships with the binary. You can't update it on the live default product page without a new version. Plan around that.
Writing it last. The subtitle is one of three indexed fields and one of two visible metadata fields. It moves the needle on both ranking and conversion. Don't draft it as an afterthought.

How to Track and Optimize Your App Subtitle

Writing a subtitle once and forgetting it is how you lose ranking. Markets shift, competitors update, and the keywords that drove installs in 2024 don't drive them in 2026.

You need to know: which subtitle keywords are actually ranking, how those rankings move week to week, and what happens when you change the copy. Without that data, you're guessing.

AppFollow gives you that visibility. Track keyword rankings tied to your subtitle across countries, monitor competitor subtitle changes the moment they happen, and measure how each subtitle update affects your impressions, conversion rate, and installs — all from one dashboard. The subtitle is too high-leverage a field to ship and forget.