Comparison

Acellus vs Readability

Price, ratings, monetisation and update history for both apps, side by side — with what reviewers say about each.

Head to head
About

Acellus

This online learning system offers a dynamic and interactive educational experience for K-12 students. It uses short video lessons and practice problems to assess understanding, with personalized instruction and real-time progress monitoring available.

Highlights
  • Self-paced learning
  • Personalized instruction
  • Live progress monitoring
  • Automatic record-keeping
  • Data-driven instruction
  • Comprehensive K-12 curriculum
Read full description

Every student learns differently. Acellus meets them where they are — with personalized, video-based K-12 instruction used by over one million students across every U.S. state. Short video lessons introduce each concept, followed by practice problems that adapt to how your student is progressing. The result: a dynamic learning experience built around the individual, not the classroom average. Learn at Their Own Pace Students work independently through concepts, with personalized instruction that helps them truly master each one before moving on. Stay in the Loop Monitor your student's progress in real time from any device. Scores, hours worked, and course progress are automatically compiled into printable reports. Always Improving Student responses are continuously analyzed and used to refine course content — so courses get more effective over time, updated daily. A Complete K-12 Curriculum Acellus covers all core subjects K-12, plus Advanced Placement (AP), Exceptional Education, Career & Technical Education, and Exam Preparation — over 470 courses in total. Learning That Goes Anywhere At school, at home, or on the go — Acellus picks up exactly where your student left off, on any device with an internet connection. Give your student the personalized education they deserve. Download Acellus today.

About

Readability

This app uses AI-powered voice technology to provide personalized reading tutoring for children. It listens as kids read aloud, offers pronunciation correction, and assesses comprehension through interactive questions. The app also builds vocabulary and allows parents to track progress.

Highlights
  • AI-powered voice recognition for reading practice
  • Real-time pronunciation correction
  • Interactive voice-based comprehension questions
  • Personalized vocabulary lists
  • Parent dashboard for progress tracking
  • Engaging grade-level stories with illustrations
Features
Read full description

Readability’s award-winning Smart Reading & Comprehension Learning App gives your child the effectiveness of 1-on-1 tutoring. Our breakthrough voice-based technology LISTENS while your child READS, highlighting, and correcting any problem words. Kids from kindergarten to 6th grade will improve their reading, vocabulary, and comprehension skills all in the convenience of a mobile app. IMPROVE READING WITH 1-ON-1 TUTORING Readability prompts your child to read aloud and listens while providing reading help and real-time pronunciation correction as your child reads. If they get stuck, they can tap on the speaker icon to have Readability read the selected passage or word aloud. Readability automatically selects the right reading material for each child to maximize improvement and minimize the reading struggle. Your child will be eager to learn as these fun and educational grade-level stories come to life with bright illustrations. IMPROVE CRITICAL THINKING SKILLS Our industry-first comprehension with Interactive Voice-based Questions & Answers (IVQA™) asks your child questions verbally about the story they just read to improve their critical thinking skills. Your child then is prompted to answer the question verbally to ensure they fully understand what they read. Comprehension is as important as reading fluency, we deliver both in our smart reading app for kids. IMPROVE VOCABULARY Readability makes it easy to learn new words and their meaning with a personalized vocabulary list for your child. Your child can long-press on any word while reading to learn its pronunciation, meaning, and add it to their vocabulary list. Their vocabulary list is neatly organized A-Z and by book to further practice, review, and perfect new or difficult words. SET AND TRACK READING GOALS Set goals and follow your child’s progress with your very own Parent Dashboard detailing what they have read, reading duration, accuracy, comprehension, and speed. It also provides daily and weekly reading reports for accountability that can be shared with a teacher. ENGAGING BOOKS A massive selection of age-appropriate stories and educational works keep kids engaged and learning. Readability is the perfect reading app for kids. Getting started is easy with a 30-day free trial. Just download the app to sign up for your free trial. Cancel anytime. SUBSCRIPTION TERMS To access all app features, please subscribe to the 30-day free trial. Your subscription automatically renews unless auto-renew is turned off at least 24-hours before the end of the current period. Your account will automatically be charged at the subscription price for renewal, within 24-hours prior to the end of the current billing period. You can manage your subscription and/or turn off auto-renewal by visiting your Account Settings after purchase. • Visit https://www.readabilitytutor.com/payment-policy/ for payment terms • Visit https://www.readabilitytutor.com/terms-of-use/ for terms of use Copyright 2023 Readability

Screenshots

Acellus4 screens
Readability4 screens

Verdict

The call

The clearest difference is in-app purchases: Acellus at none against Readability's 2. Readability's advantage is update cadence (fortnightly vs every 3 months) and review sentiment (56% vs 36%). On price, rating, ratings volume and ads there is nothing between them.

Scored on Price · Rating · Positive reviews · Number of ratings · Update frequency · Ads · In-app purchases · Monetization · Best chart rank · Devices · Requires iOS

CostPrice · In-app purchases · Ads · Monetization

Both are free to download. Readability sells 2 in-app purchases, starting at $19.99 per month. Acellus asks for nothing beyond the download.

ReceptionRating · Positive reviews · Number of ratings

On the App Store both sit at effectively the same score — 4.5 for Acellus against 4.6 for Readability. Both are backed by a comparable volume of ratings — 32K and 25K respectively. Written reviews are what separate them: 36% of Acellus's written reviews are positive against 56% of Readability's.

UpkeepUpdate frequency

Acellus ships an update every 3 months, Readability fortnightly. Both last shipped on October 18, 2026.

Scorecard5 real differences · 6 level
Acellus versus Readability: the parameters behind the verdict, then further details
ParameterAcellusReadability
PriceFreeFree
Rating4.5 (32K ratings)4.6 (25K ratings) — better
Positive reviews35.9% of reviews55.6% of reviews — better
Number of ratings32K — better25K
Update frequencyEvery 3 monthsFortnightly — better
AdsNoNo
In-app purchasesNo — betterYes
MonetizationFree — betterSubscription
Best chart rank—#152 — better
DevicesiPhone, iPadiPhone, iPad
Requires iOS16.416.4
Further details — not scored
Size7 MB282 MB
Age rating4+4+
DeveloperGoldKey Security Corporatione4site Inc.

Customer experience

Acellus

All ratings31,649 ratings
Positive87.6%
Neutral3.2%
Negative9.2%
Written reviews516 reviews
Positive35.9%
Neutral15.3%
Negative48.8%

Readability

All ratings24,505 ratings
Positive90.5%
Neutral4.0%
Negative5.5%
Written reviews374 reviews
Positive55.6%
Neutral9.6%
Negative34.8%

User reviews

Acellus

From 32K App Store ratings

What we love

  • 👍 Easy to navigate classes
  • 👍 Engaging and interactive lessons
  • 👍 Flexible and self-paced learning
  • 👍 Helpful and fun teachers
  • 👍 Ability to track progress and compete with friends

Room to improve

  • 🐛 Occasional crashes and freezes
  • 🐛 Incorrect answers marked as wrong
  • 🐛 Lessons not always aligned with assessments
  • 🐛 Boring or gimmicky teaching styles in some courses
  • 🐛 Lack of live teacher interaction and support

Readability

From 25K App Store ratings

What we love

  • 👍 Helpful for struggling readers
  • 🚀 Improves reading fluency
  • 💡 Engaging for kids
  • 👍 Useful data and progress tracking

Room to improve

  • 🐛 Voice recognition issues
  • 🐛 Inaccurate comprehension tests
  • 💰 Expensive subscription
  • 🐛 Glitchy performance

Bugs and requests

Acellus

Reported bugs

4 issues
  • Videos randomly restarting or freezing
  • Incorrect grading of written assignments
  • Inability to review past lessons and videos
  • Courses not properly syncing progress across devices

Requested features

5 requests
  • Add subtitles or transcripts for videos
  • Allow skipping of videos if content is already understood
  • Improve mobile app usability and stability
  • Provide more hands-on and interactive learning experiences
  • Offer more personalized learning paths and feedback

Readability

Reported bugs

4 issues
  • App charges for free trial
  • Subscription cancellation issues
  • Inconsistent app behavior
  • Compatibility problems on some devices

Requested features

4 requests
  • More customization options for text and background
  • Improved voice recognition accuracy
  • Expanded book selection
  • Better comprehension testing

In-app purchases

None

Acellus

No in-app purchases

2 purchases

Readability

Subscriptions2
  • Readability Tutor1 Month trial$19.991 Month
  • Readability Tutor Annual1 Month trial$139.991 Year

Questions

Is Acellus free?
Acellus is free to download, with no in-app purchases.
Is Readability free?
Readability is free to download, with in-app purchases available.
Which has better reviews, Acellus or Readability?
Readability is rated higher. Acellus averages 4.5 out of 5 from 32K ratings, while Readability averages 4.6 from 25K ratings.
Do Acellus or Readability have ads?
Neither Acellus nor Readability shows ads.
Which is updated more often, Acellus or Readability?
Acellus ships an update every 3 months, and Readability fortnightly. Most recently, Acellus was updated on October 18, 2026 and Readability on October 18, 2026.

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