Comparison

Zero Deficit vs BrainRock

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

Head to head
About

Zero Deficit

Prepare for your CCRN exam with a comprehensive study tool built by an ICU nurse. It offers over 695 practice questions with detailed rationales, AI-powered personalization, smart flashcards, and full-length simulation exams to identify and address knowledge gaps.

Highlights
  • 695+ high-yield practice questions
  • Detailed rationales for every question
  • AI-powered personalized study guides
  • 190+ smart flashcards with spaced repetition
  • Full-length simulation exams
  • Detailed performance analytics
  • Exclusive cheat sheets
Features
Read full description

Pass the CCRN exam with Zero Deficit — critical care nursing certification prep built by ICU nurses who actually passed. EVERYTHING YOU NEED TO PASS • 695+ CCRN practice questions with detailed rationales, covering every body system on the AACN exam blueprint • 8 in-depth study guides weighted exactly like the real exam: Cardiovascular (17%), Respiratory (15%), Multisystem (14%), Neurology (12%), Renal, GI, Endocrine, Hematology • 200-question timed CCRN exam simulation with scoring and a readiness level • Two 100-question practice quizzes to build test-day stamina • AI-powered question generator that creates fresh questions tuned to your weak areas • Spaced-repetition flashcards based on cognitive science • High-yield cheat sheets and question-breakdown strategy training ICU CLINICAL REFERENCE • 77-medication ICU drug reference: vasopressors, sedation, anticoagulants, antiarrhythmics and more — with typical dose ranges • Hemodynamic monitoring guide: normal values, PA catheter waveforms, shock profiles • Shock, ABG and arrhythmia flowcharts for rapid review STAY ON TRACK • Exam countdown with readiness tracking • Daily question notifications that keep your streak alive • Progress analytics by body system so you always know where to focus • Study streaks, achievements and a weekly leaderboard BUILT FOR ICU NURSES, BY ICU NURSES Every feature came from real feedback during the 30 most stressful days before exam day. 12-hour shift followed by a 2-hour study session? We built the app we wish we'd had. STUDY ANYWHERE Print any study guide as a clean, formatted PDF for break-room review. All 8 body-system study guides and their quizzes are free — no account required. WHO USES ZERO DEFICIT • ICU registered nurses preparing for AACN CCRN (Adult) certification • CVICU, MICU, SICU, NSICU and CCU staff • ER nurses transitioning to critical care • Travel nurses studying between assignments • Nurse managers earning the CCRN to stay clinical SIMPLE PRICING Free: all 8 body-system study guides + system quizzes. A free account starts a 3-day full-access trial — no credit card required. Go premium with Monthly, Yearly or Lifetime access (auto-renewable subscription or one-time lifetime purchase) to unlock the full question bank, exam simulation, cheat sheets, ICU drug reference and flashcards. Content is written and source-checked against FDA labels and major clinical guidelines (AHA/ACLS, Surviving Sepsis Campaign, SCCM). Educational material — not medical advice. CCRN® is a registered trademark of AACN Certification Corporation. Zero Deficit is an independent study platform and is not affiliated with or endorsed by AACN.

About

BrainRock

Features
Read full description

Learning a language should feel simple—not like homework. Tell BrainRock what you want to learn: travel phrases, everyday conversation, work, exams, or a hobby. AI instantly creates a vocabulary pack matched to your level, with useful examples and clear pronunciation. No deck building. No overwhelming lessons. Just a few useful words at a time. WHY BRAINROCK FEELS EASY • Learn words you actually want to use • Start in seconds from a topic or photo • Listen and repeat with audio pronunciation • Lock in memory with quick quizzes • Keep momentum with daily review reminders • Watch your progress grow as you level up PERFECT FOR Travel, conversation, TOEIC, TOEFL, JLPT, HSK, TOPIK, DELE, business, and everyday vocabulary. Pick a topic. Learn for a few minutes. Come back tomorrow. Small sessions turn into real progress. Terms of Use (EULA): https://www.apple.com/legal/internet-services/itunes/dev/stdeula/ Privacy Policy: https://rockparks.com/brainrock/privacy.html

Screenshots

Zero Deficit4 screens
BrainRock4 screens

Verdict

The call

The clearest difference is in-app purchases: BrainRock at none against Zero Deficit's 3. On price, update cadence, ads and device support 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. Zero Deficit sells 3 in-app purchases, starting at $14.99 per month. BrainRock asks for nothing beyond the download.

UpkeepUpdate frequency

Both ship on a similar rhythm, roughly weekly. The most recent releases landed on October 10, 2026 and October 5, 2026 respectively.

Scorecard1 real difference · 9 level
Zero Deficit versus BrainRock: the parameters behind the verdict, then further details
ParameterZero DeficitBrainRock
PriceFreeFree
Rating5.0 (4 ratings) — better—
Positive reviews100.0% of reviews—
Number of ratings4 — better—
Update frequencyWeeklyWeekly
AdsNoNo
In-app purchasesYesNo — better
MonetizationFree with in-app purchases—
DevicesiPhone, iPad, iPodiPhone, iPad, iPod
Requires iOS15.015.0
Further details — not scored
Size3 MB164 MB
Age rating12+4+
DeveloperZERO DEFICIT LLCHAYOUNG KOH

In-app purchases

3 purchases

Zero Deficit

Subscriptions2
  • Zero Deficit CCRN PREP MONTHLY3 Days trial$14.991 Month
  • Zero Deficit CCRNPrep PremiumAnnual$84.991 Year
One-time1
  • Zero Deficit CCRN Prep Lifetime$199.99
None

BrainRock

No in-app purchases

Questions

Is Zero Deficit free?
Zero Deficit is free to download, with in-app purchases available.
Is BrainRock free?
BrainRock is free to download, with no in-app purchases.
Do Zero Deficit or BrainRock have ads?
Neither Zero Deficit nor BrainRock shows ads.
Which is updated more often, Zero Deficit or BrainRock?
Zero Deficit ships an update weekly, and BrainRock weekly. Most recently, Zero Deficit was updated on October 10, 2026 and BrainRock on October 5, 2026.

Other comparisons