Comparison

The Fourth Dimension vs Testseries Alchemys

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

Head to head
About

The Fourth Dimension

Explore a complex mathematical concept through an interactive 3D experience. This app uses a unique touch interface to help you visualize and understand the fourth dimension in an engaging and accessible way.

Highlights
  • Interactive 3D touch interface
  • Explains the fourth dimension
  • Accessible language for all
  • 30-page interactive book
  • Visual and hands-on learning
Read full description

The Fourth Dimension is a 30-page interactive book that explains a single mathematical idea in language that anyone can understand. Instead of static images or canned videos, this app employs a unique 3D touch interface that lets you literally grasp the concept of the fourth dimension with your own hands. “Not only can you blow your own mind over and over again, you can also enjoy watching your friends’ minds being blown in front of you.” — Cult of Mac “One of the coolest apps I've ever used... The Fourth Dimension is to boring learning apps what Carl Sagan's Cosmos was to staid science documentaries.” — BuzzFeed “The app is very cool, and it's unlike pretty much anything we've seen in the App Store.” — The Verge “This is one of my most favorite iOS apps ever.” — George Musser, contributing editor for Scientific American and author of The Complete Idiot's Guide to String Theory (App Store user reviews follow.) “Blew my mind. I generally don't use 'learning' apps as they're mostly gimmicks. This one, though, truly made me think. I hope this developer comes out with more outstanding apps such as this one. Bravo!” — Iceitic “Astounding. That some people care passionately enough about tesseracts to go create a fantastic app for others to understand them is incredible. The app is extremely well designed, wittily written, and executed with love. That alone is worth buying it, besides the fact that I learned what the hell a tesseract was.” — Duncan MacMichael “Fantastic! This is what someone really smart, and who really knows how to teach well, can do with a tablet. And the authors are funny, too, which is a neat bonus.” — DNY “Fantastic app. I work at a leading UK university. If only all our material was this well written and presented. Definitely worth buying and then spending a bit of time with over a day or two to get your head around the fourth dimension. Great app!” — JulesFM “Great job! This app does the best job explaining the 4th dimension. Why learn it in some boring classroom when here you can have an interactive and visual explanation.” — Aco Strklalj Over 250,000 people have blown their minds with this app.

About

Testseries Alchemys

Read full description

Get Personalized Learning Outcomes for everyone. An in-depth performance analysis, where you can know your strong and weak points, your all India rank, your state rank etc. You will also get a virtual tutor who is completely dedicated to bringing out the best in you. It will prioritize your concepts, chapters, topics, and questions through machine learning. Get this innovative learning experience only on Testseries Alchemys!!

Screenshots

The Fourth Dimension4 screens
Testseries Alchemys4 screens

Verdict

The call

The clearest difference is price: Testseries Alchemys at Free against The Fourth Dimension's $2.99. The Fourth Dimension's advantage is in-app purchases (none vs 10) and update cadence (every 4 months vs every 12 months). On ads, device support 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

Testseries Alchemys is free to download; The Fourth Dimension costs $2.99 up front. Testseries Alchemys sells 10 one-off in-app purchases. The Fourth Dimension asks for nothing beyond the download.

UpkeepUpdate frequency

The Fourth Dimension ships an update every 4 months, Testseries Alchemys every 12 months. The most recent releases landed on November 10, 2026 and November 8, 2026 respectively.

Scorecard3 real differences · 7 level
The Fourth Dimension versus Testseries Alchemys: the parameters behind the verdict, then further details
ParameterThe Fourth DimensionTestseries Alchemys
Price$2.99Free — better
Rating4.8 (1.9K ratings) — better—
Positive reviews94.2% of reviews—
Number of ratings1.9K — better—
Update frequencyEvery 4 months — betterEvery 12 months
AdsNoNo
In-app purchasesNo — betterYes
MonetizationFree with in-app purchases—
DevicesiPhone, iPad, iPodiPhone, iPad, iPod
Requires iOS15.0 — better15.5
Further details — not scored
Size5 MB146 MB
Age rating+44+
DeveloperLunar Skydiving LLCOnline Learning

In-app purchases

None

The Fourth Dimension

No in-app purchases

10 purchases

Testseries Alchemys

One-time10
  • Package - 21900$199.99
  • Package - 19900$199.99
  • Package - 29900$299.99
Show 7 more
  • Package - 27900$299.99
  • Package - 34900$349.99
  • Package - 54900$499.99
  • Package - 59900$599.99
  • Package - 69900$699.99
  • Package - 79900$799.99
  • Package - 89900$899.99

Questions

Is The Fourth Dimension free?
The Fourth Dimension costs $2.99, with no in-app purchases.
Is Testseries Alchemys free?
Testseries Alchemys is free to download, with in-app purchases available.
Do The Fourth Dimension or Testseries Alchemys have ads?
Neither The Fourth Dimension nor Testseries Alchemys shows ads.
Which is updated more often, The Fourth Dimension or Testseries Alchemys?
The Fourth Dimension ships an update every 4 months, and Testseries Alchemys every 12 months. Most recently, The Fourth Dimension was updated on November 10, 2026 and Testseries Alchemys on November 8, 2026.

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