Comparison

Size test vs NBack³

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

Head to head
About

Size test

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This app is designed to assess how quickly the user reacts to changes in the size of an object. Users can select one of the test modes: 'Increasing the object', 'Decreasing the object', 'Decreasing or increasing the object'. When the user observes a change in the size of an object, the user must break contact with the device screen. The recorded test time reflects the user's ability to perceive the change in object size. Once the test is completed, the results are tested for normality of distribution (Shapiro-Wilk test). If the values deviate from the law of normal distribution, the program analyzes the data sets, removes the worst value and adds an additional attempt. In the program settings you can select the number of attempts - from 10 to 30. The choice of the number of attempts depends on the performer's age and professional activity. In addition, in the program settings the user can save a backup copy of his measurements in JSON format anywhere (Save backup), add measurements from another device (Add backup), replace already saved measurements with new ones (Replace backup) or delete all data (Delete all data). This application is intended to be used by athletes and teachers in specialized educational institutions for scientific research.

About

NBack³

This brain training app uses the scientifically proven Dual N-Back method to enhance cognitive functions like working memory, focus, and decision-making. It offers adjustable difficulty levels and tracks progress with a visually engaging interface.

Highlights
  • Dual N-Back method
  • Adjustable difficulty (n=1-5)
  • Enhances working memory
  • Improves inhibitory control
  • Develops attention skills
  • Progress tracking
  • Streak bonus system
Features
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■ NBack³: The Scientifically Proven Brain Training Game ■ "My memory isn't what it used to be..." "I can't seem to stay focused..." "I want to sharpen my split-second decision-making..." If these sound familiar, NBack³ is the ultimate brain training app designed just for you. ◆ The Ultimate Workout for Your Working Memory ◆ Based on "Dual N-Back" research—a method scientifically proven to enhance cognitive function—NBack³ takes brain training to the next level. Working memory is your brain's ability to temporarily hold and process information. It is the vital foundation for memory, focus, and logical reasoning. ◆ Simple to Play ◆ Memorize the Position, Color, and Character shown on a 3×3 grid. Identify if the current tile matches the one shown "n-steps" ago. Fully adjustable difficulty levels from n=1 to n=5. ◆ 5 Cognitive Functions You’ll Sharpen ◆ Working Memory: Enhance your "mental scratchpad." Inhibitory Control: Filter out distractions and irrelevant info. Selective & Divided Attention: Focus on multiple streams of data simultaneously. Visuospatial Cognition: Recognize spatial relationships with precision. Multitasking Decisiveness: Handle multiple tasks with ease. ◆ Key Features of NBack³ ◆ Stunning Neon UI: A beautiful, modern design for an immersive experience. Dynamic Difficulty: Adjustable n-levels (1–5) to match your progress. Streak Bonus System: Stay sharp and rack up consecutive correct answers. Intuitive Controls: Smooth and responsive gameplay. Quick Sessions: 20-turn sets allow for efficient training in minutes. Progress Tracking: Keep motivated by tracking your scores. Smart Reminders: Daily notifications to keep your streak alive. Personal Bests: Record your highest scores for each N-level. ◆ Perfect For... ◆ Students aiming to boost memory and learning. Professionals looking to improve workplace productivity. Health-conscious individuals interested in brain longevity. Seniors working to prevent cognitive decline. Gamers who love a mental challenge. ◆ The Science ◆ N-back training has been widely reported in research to improve fluid intelligence and cognitive performance. By processing position, color, and character simultaneously, NBack³ delivers a "Triple N-Back" challenge that provides a higher cognitive load for more effective results. ◆ Consistency is Key ◆ Brain training works best when it's a habit. NBack³ is designed to be completed in just a few minutes, making it perfect for your commute or a quick break. Sharpen your mind with the scientifically-backed power of NBack³! Terms of Use: https://planet-firewall-419.notion.site/25d6c3f9d1f680b29d72e5cef4be6fbf Privacy Policy: https://www.notion.so/NBack-1f06c3f9d1f6807aa983c83530910b0d Subscription Details: Premium Plan: 120 JPY / month (tax incl.) Auto-Renewal: Can be canceled up to 24 hours before the period ends. Management: App Store Settings > Subscriptions

Screenshots

NBack³3 screens

Verdict

The call

The clearest difference is price: NBack³ at Free against Size test's $0.99. NBack³ also leads on update cadence (every 4 days vs every 10 months). Size test's advantage is in-app purchases (none vs 1) and ads (none vs shown). On 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

NBack³ is free to download; Size test costs $0.99 up front. NBack³ sells 1 in-app purchase, starting at $0.49 per month. Size test asks for nothing beyond the download.

UpkeepUpdate frequency

Size test ships an update every 10 months, NBack³ every 4 days. The most recent releases landed on October 29, 2026 and November 5, 2026 respectively.

Scorecard5 real differences · 3 level
Size test versus NBack³: the parameters behind the verdict, then further details
ParameterSize testNBack³
Price$0.99Free — better
Positive reviews—71.4% of reviews
Update frequencyEvery 10 monthsEvery 4 days — better
AdsNo — betterYes
In-app purchasesNo — betterYes
Monetization—Free with in-app purchases
DevicesiPadiPhone, iPad — better
Requires iOS14.0 — better17.0
Further details — not scored
Size1 MB20 MB
Age rating4+4+
DeveloperViacheslav RomanenkoTaiki Nishimura

In-app purchases

None

Size test

No in-app purchases

1 purchases

NBack³

Subscriptions1
  • プレミアムプラン$0.491 Month

Questions

Is Size test free?
Size test costs $0.99, with no in-app purchases.
Is NBack³ free?
NBack³ is free to download, with in-app purchases available.
Do Size test or NBack³ have ads?
NBack³ shows ads; Size test does not.
Which is updated more often, Size test or NBack³?
Size test ships an update every 10 months, and NBack³ every 4 days. Most recently, Size test was updated on October 29, 2026 and NBack³ on November 5, 2026.

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