How to Use ASOhack's Keyword Density Checker (Step-by-Step Guide)

You just spent two hours rewriting your app's metadata. The title feels tight, the subtitle is punchy, and the keyword field is maxed out. But are the right words actually appearing at the right frequency across every field? And have you wasted any of those precious 100 iOS keyword-field characters repeating a term already in your title?

That's exactly what ASOhack's Keyword Density Checker is built to answer. No signup, no credit card — paste your metadata in and get a clear breakdown in under ten seconds. This guide walks you through every part of the tool and explains what to do with each number it gives you.

What Does Keyword Density Mean for Apps?

Keyword density in traditional web SEO measures how often a word appears in a page's body text as a percentage of total word count. The logic is straightforward: if a keyword appears too rarely, the page might not rank for it; if it appears too often, it looks spammy.

App store optimisation works differently — and the platform you're targeting changes the rules significantly.

On iOS (App Store), Apple indexes four fields:

• App name (30 characters)
• Subtitle (30 characters)
• Keyword field (100 characters, comma-separated, hidden from users)
• In-app purchase names

Apple does not index the long description. A user reading your App Store description will see it, but Apple's search algorithm will not. This means every single character in your keyword field is doing indexing work, while your description is purely a conversion tool.

On Android (Google Play), Google indexes:

• App title (30 characters)
• Short description (80 characters)
• Long description (4,000 characters)

There is no separate keyword field. Google's algorithm treats the long description much like it treats a web page — keyword placement and natural density in the body text genuinely affects rankings. Repeating a keyword three or four times across 4,000 characters is sensible; repeating it twenty times is keyword stuffing and can hurt you.

Understanding these differences is the foundation of why the density checker matters. A word that appears twice in your iOS title is already heavily weighted — adding it to the keyword field is a waste of space. On Android, a primary term appearing just once in 800 words of description might be leaving ranking signal on the table.

For a deeper primer on ASO fundamentals before you dive in, see the ASO guide for beginners.

How to Run Your First Check

Open /tools/keyword-density in any browser. The tool is completely free and requires no account.

You'll see four labelled text areas:

1. App Name / Title — paste your full app title here
2. Subtitle / Short Description — for iOS this is the 30-character subtitle; for Android use the 80-character short description
3. Keyword Field — iOS only; paste the comma-separated keyword string exactly as it appears in App Store Connect
4. Description — paste your full long description

Fill in as many fields as apply to your platform. If you're on iOS and have no long description strategy, you can leave that field blank and still get useful output. Hit Analyse.

That's it. The results appear instantly below the form.

How to Read the Density Report

The output is split into four sections. Here's what each one tells you.

Single Keyword Frequency Table

This table lists every word found across all your fields, sorted by density percentage (highest first). Each row shows the word, how many times it appears in total, and its density as a percentage of the combined word count.

A word sitting at 4–6% across your metadata is prominent. A core feature term at 0.3% is barely present. Use this table as your first diagnostic: are the words you want to rank for near the top of the list, or are they buried below filler words like "experience" and "amazing"?

Bigram Frequency (Two-Word Phrases)

Single words rarely tell the whole story. "Workout" at 3% is useful, but "workout tracker" as a bigram tells you whether your most important phrase is actually appearing as a unit. The bigram table works the same way — sorted by density, showing count and percentage.

If a high-value phrase from your keyword research isn't showing up as a bigram at all, your metadata might be separating the two words across different fields, which weakens the phrase signal.

Character Count vs. Platform Limits

Below the frequency tables, each field shows its current character count alongside the platform limit:

Fields that exceed their limit are flagged in red. Fields that are empty or well under their limit are flagged in amber — these represent wasted indexing opportunity. A subtitle sitting at 18 of 30 characters is leaving 12 characters of prime iOS ranking space unused.

Over-Limit and Empty Field Warnings

The tool surfaces a plain-language warning for any field that needs attention:

• Over limit — you need to cut; the store will either truncate or reject the metadata
• Empty — you're leaving indexable space blank
• Well under limit — worth expanding if you have relevant terms to add

What Changes to Make

The density report is only as useful as the action you take on it. Here's a practical decision framework for each scenario you'll encounter.

High-density words already in your title or subtitle. If "budget" appears in your iOS title and is also sitting in your 100-character keyword field, remove it from the keyword field. Apple already indexes your title — duplicating terms in the keyword field is a confirmed waste of space. Every character freed up can hold a new term. This is one of the most common mistakes developers make when building out their first listing.

Important words with 0% density in visible fields. If a term from your keyword research has zero appearances in your title, subtitle, or description, it only exists in the hidden keyword field on iOS — or doesn't exist at all. Consider whether it should be elevated into a visible field for both indexing weight and conversion impact.

Android description below 3% for your primary keyword. Google treats the long description as body copy. If your main category term appears once in a 600-word description, the signal is weak. Find two or three natural sentences where you can use it in context. Don't stuff — aim for the same density you'd target in a well-written web article (roughly 1–3%).

Character limits not met. If your iOS subtitle is at 15 of 30 characters, brainstorm keyword-rich phrases that fill the gap. "Task Manager & Planner" uses 22 characters and adds two indexable terms. On Android, an 80-character short description sitting at 40 characters is similar: expand it with a benefit statement that includes your core term.

For a full metadata audit beyond just density, pair this tool with the ASO Audit tool, which checks your entire listing against platform guidelines.

Common Mistakes the Tool Finds

Working through hundreds of real app listings surfaces the same errors repeatedly. The density checker will catch all of these immediately.

Brand name in the keyword field. Your app name is already indexed. Putting your brand name in the iOS keyword field wastes characters that could hold a unique search term. If your app is called "Lumio" and "Lumio" appears in your keyword field, that's up to five characters thrown away.

Plurals alongside their stem. Including both "workout" and "workouts" in the keyword field is redundant. Apple's algorithm handles basic pluralisation — one form is enough. The density checker will show both appearing at low counts, which is a signal to pick one and use that character for a different term. Use the Keyword Explorer to check which form has higher search volume before deciding.

Stop words eating character budget. Articles, prepositions, and conjunctions (the, for, with, and, to) are not indexed by Apple. The density checker's frequency table will show these near the top of the list at high percentages — if they're coming from your keyword field rather than your description, that's characters you should reclaim.

Over-repeating in Android descriptions. The bigram table will show a phrase appearing eight or ten times across 800 words. Google sees this as stuffing. Cut it back to three or four natural uses and use the freed-up space to cover related subtopics, which broadens your keyword coverage without the spam signal.

Worked Example: A Fitness App Listing

Here's what the output looked like for a sample fitness tracking app run through the tool.

Inputs used:

• Title: "FitLog — Workout Tracker"
• Subtitle: "Log gym sets & cardio"
• Keyword Field: workout,gym,fitness,exercise,training,log,sets,reps,cardio,running,strength,weight,lifting,tracker,bodybuilding
• Description: 320 words covering workout logging, progress charts, and personal records

What the density checker found:

The single-keyword table showed "workout" at 4.2% and "tracker" at 3.8% — both already prominent in the title and subtitle. Both also appeared in the keyword field, consuming 16 characters combined.

"Gym" appeared at 1.1% (once in the subtitle, once in the keyword field). The bigram table showed "gym workout" had zero appearances — a missed phrase that users frequently search.

The iOS subtitle was at 21 of 30 characters. Nine characters were unused. Changing the subtitle to "Log gym sets, reps & cardio" filled the gap and added "reps" as a unique indexed term.

After removing "workout" and "tracker" from the keyword field (already in the title), 14 characters became available. Adding "hiit,plank,pb" used 12 of those characters and introduced three new indexable terms.

The character count section flagged the description as blank for the Android run — a reminder that the listing hadn't been adapted for Play Store at all.

FAQ

Does keyword density matter for iOS rankings?

Not in the traditional web SEO sense. Apple's algorithm is not counting raw occurrences across your description. What matters on iOS is which fields a keyword appears in (title and subtitle carry the most weight) and that your 100-character keyword field contains unique, non-duplicate terms. Use the density checker mainly to catch duplication and wasted character space.

How often should I re-run the density check?

Any time you make a change to your metadata, run it again. A good habit is to run the check as the final step before submitting a new version in App Store Connect or the Play Console. It takes ten seconds and catches errors that are easy to overlook when you're editing line by line.

Can I use the tool for both iOS and Android at the same time?

Yes. Paste all relevant fields — title, subtitle/short description, keyword field (iOS), and long description — and the tool analyses them together. The character count section shows iOS and Android limits side by side, so you can evaluate your listing for both platforms in a single pass.

My description density for my main keyword is 4% on Android. Is that too high?

It depends on the word count. For a 4,000-character description (roughly 600–700 words), a 4% density means appearing around 25 times — that's likely stuffing. For a short 150-word description, 4% is around six appearances, which is still on the high side. Aim for the keyword to appear naturally two to four times in a standard-length description and let related terms (synonyms, feature names, use cases) carry the rest of the semantic load.

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Running the Keyword Density Checker takes less time than writing a single sentence of metadata. The questions it answers — is my character budget fully used, am I duplicating terms, is my primary keyword actually prominent — are the same questions every ASO practitioner runs through manually. The tool just does it in seconds and shows the numbers in a format that makes the next action obvious.

Once your density looks clean, the logical next step is a full metadata audit with the ASO Audit tool, or expanding your keyword list with the Keyword Explorer.