Comparison

4thirTEEN vs RecallOS

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

Head to head
About

4thirTEEN

Features
Read full description

This app will empower you to stay connected to the daily happenings of our organization. It will unite teens locally and regionally, offering a safe space to embrace their true selves without fear of judgment. This app will help you stay connected with our media, events, and volunteer opportunities. Mobile app version: 6.22.1

About

RecallOS

Enhance knowledge retention for students and healthcare professionals with AI-powered study tools. Utilize active recall, adaptive quizzing, and personalized learning paths to master complex subjects and track your progress effectively.

Highlights
  • Daily recall paths
  • AI-powered study materials
  • Adaptive quizzing
  • Smart flashcards
  • Study Buddy AI
  • Weakness detection
  • Progress tracking
Features
Read full description

RecallOS is the daily learning habit for healthcare students — wake up your brain, stay sharp, and walk into your boards confident instead of crammed. Built on active recall and spaced repetition, RecallOS turns a few focused minutes a day into long-term retention across nursing, anesthesia (CRNA/SRNA), NP, PA, pharmacology, physiology, and advanced clinical topics. THE DAILY RECALL RUN Your core habit: a short, guided daily session that brings back what you're about to forget and turns every miss into tomorrow's review. Finish to open a reward chest, grow your streak, and climb the league. BUILD THE HABIT • Streaks, daily chests, XP, and missions that make showing up feel good • Leagues and friend challenges to stay motivated with others • Recall DNA — a living snapshot of your accuracy and weakest topics • Progress tracking for streaks, recall performance, and consistency STUDY YOUR OWN MATERIAL (RecallOS Pro) Upload your notes, PDFs, and slides to instantly generate: • Practice quizzes • Smart flashcards • Study guides • Concept reviews Plus Study Buddy AI for explanations and concept breakdowns, adaptive weakness tracking that focuses your time where it counts, and personalized study plans. NCLEX READINESS A free NCLEX readiness scan for everyone, with a full board-style question bank, custom topic mapping, and exam-readiness prediction on Pro. PLANS • RecallOS Free — Daily Recall Run, streaks, the free NCLEX scan, and daily weakness practice • Recall+ (US$1.99/month) — everything in Free, plus friend challenges and unlimited seeded weakness drills • RecallOS Pro (US$9.99/month) — the full AI study suite: document uploads, quiz/flashcard/study-guide generation, Study Buddy AI, adaptive weakness tracking, and complete NCLEX prep WHO IS RECALLOS FOR? • Nursing students • Nurse anesthesia students (CRNA/SRNA) • Advanced practice nursing, NP, and PA students • Healthcare professionals and pre-health students • Lifelong learners seeking stronger retention and recall IMPORTANT INFORMATION RecallOS is an educational tool and is not intended to provide medical advice, diagnosis, or treatment recommendations. AI-generated educational content may contain inaccuracies. Users should independently verify important information and rely on approved educational resources, clinical guidance, and professional judgment. RecallOS is not affiliated with, endorsed by, or sponsored by any educational institution, certification organization, licensing board, or examination provider. Recall+ (US$1.99/month) and RecallOS Pro (US$9.99/month) are auto-renewable subscriptions. Payment is charged to your Apple ID at confirmation of purchase. Subscriptions automatically renew at the same price unless auto-renew is turned off at least 24 hours before the end of the current period. Manage or cancel anytime in your Apple ID account settings. Terms of Use (EULA): https://recallos.co/terms Privacy Policy: https://recallos.co/privacy Subscription Terms: https://recallos.co/subscription-terms

Screenshots

4thirTEEN3 screens
RecallOS4 screens

Verdict

The call

The clearest difference is in-app purchases: 4thirTEEN at none against RecallOS's 10. 4thirTEEN also leads on ads (none vs shown) and device support (4 vs 2). RecallOS's advantage is update cadence (every 6 days vs every 6 months). On price and iOS requirement 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. RecallOS sells 10 in-app purchases, starting at $0.99 per month. 4thirTEEN asks for nothing beyond the download.

UpkeepUpdate frequency

4thirTEEN ships an update every 6 months, RecallOS every 6 days. The most recent releases landed on November 8, 2026 and November 10, 2026 respectively.

Scorecard4 real differences · 6 level
4thirTEEN versus RecallOS: the parameters behind the verdict, then further details
Parameter4thirTEENRecallOS
PriceFreeFree
Rating—5.0 (4 ratings) — better
Positive reviews—100.0% of reviews
Number of ratings—4 — better
Update frequencyEvery 6 monthsEvery 6 days — better
AdsNo — betterYes
In-app purchasesNo — betterYes
Monetization—Free with in-app purchases
DevicesiPhone, iPad, iPod, Apple TV — betteriPhone, iPod
Requires iOS15.115.0 — better
Further details — not scored
Size55 MB30 MB
Age rating4+17+
Developer4thirTEENCaleb Tolbert

In-app purchases

None

4thirTEEN

No in-app purchases

10 purchases

RecallOS

Subscriptions5
  • RecallOS+7 Days trial$0.991 Month
  • Recall+7 Days trial$1.991 Month
  • RecallOS Plus7 Days trial$5.991 Month
Show 2 more
  • RecallOS Pro7 Days trial$9.991 Month
  • RecallOS Pro Annual$99.991 Year
One-time5
  • 25 Gem Pack$0.99
  • Streak Restore$0.99
  • 60 Gem Pack$1.99
Show 2 more
  • 175 Gem Pack$4.99
  • 400 Gem Pack$9.99

Questions

Is 4thirTEEN free?
4thirTEEN is free to download, with no in-app purchases.
Is RecallOS free?
RecallOS is free to download, with in-app purchases available.
Do 4thirTEEN or RecallOS have ads?
RecallOS shows ads; 4thirTEEN does not.
Which is updated more often, 4thirTEEN or RecallOS?
4thirTEEN ships an update every 6 months, and RecallOS every 6 days. Most recently, 4thirTEEN was updated on November 8, 2026 and RecallOS on November 10, 2026.

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