Comparison

Universe Splitter vs Countdown Star (Ad

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

Head to head
About

Universe Splitter

This app uses quantum physics to help you make decisions. Input two choices, and it uses a remote quantum device to determine which reality you end up in, allowing you to live out both outcomes in separate universes.

Highlights
  • Quantum decision-making
  • Splits universes based on choices
  • Uses remote quantum device
  • Based on many-worlds interpretation
  • Original and acclaimed app
Features
Read full description

Use Quantum Physics to Split Your Universe -- It's the Ultimate Decision-Maker THIS IS THE ORIGINAL! • An App Store "Top Paid App" • An App Store "Staff Favorite" • Endorsed by famous physicists And recently featured in: • "Something Deeply Hidden" best-selling book by Sean Carroll • "The Joe Rogan Experience" podcast • "This American Life" podcast "According to quantum mechanics, every observation brings new universes into existence. But these universes have been completely useless to us -- until now! Universe splitter helps guarantee that there's at least one version of you who has made all the right choices." -- Sean Carroll, physicist at Caltech and best-selling author "The functioning of this app is in complete agreement with the many-worlds interpretation of quantum mechanics." -- Garrett Lisi, PhD, Theoretical Physics Scientists say that every quantum event plays out simultaneously in every possible way, with each possibility becoming real in a separate universe. But that was just an abstract concept... until now! Because now, you can harness this powerful and mysterious effect right from your iPhone. When faced with a tough choice, Universe Splitter allows you to live out BOTH of your options... in separate realities.* No mere coin-flip app can make this claim! Here's how it works: Let's say you have to make a difficult decision — for example, whether to accept a job offer or to turn it down. Just type both actions into your Universe Splitter, and press the "Split Universe" button. Universe Splitter will then, over the internet, activate a remote "Quantis" brand quantum device (made by id Quantique, and certified by the National Metrology Institute of Switzerland) which will send a single photon into a quantum "either/or" state. According to current scientific thinking, though, the photon will actually be in a "both, but in separate universes" state! Within seconds, Universe Splitter will report to you which of those two universes you’re in, and by taking a different action in each, you will cause these previously identical universes to diverge.* Of course, you won't be able to see or interact with that other universe. In fact, you may question whether anything at all happened. But according to the prevailing quantum theory, there will be two of you pondering whether anything just happened! Right now you're probably wondering: Does this app genuinely contact a quantum device in Geneva? YES, it absolutely does, and we would be happy to provide proof of this upon request. Email eric@aerfish.com for more info. As BDembko writes: "The real joke... is that it's NOT a joke. Which actually makes it funnier, if you ask me. (Kind of an Andy Kaufman kind of thing) The guy actually went the extra 10 miles... and it seems so absurd to us, that we figure it's a joke. But it's not... which then means it is. This is seriously quantum humor to the extreme." And -- if an infinite supply of universes isn't enough for you -- this app also gives you stylish, retro, machine-age graphics (complete with industrial-strength sound effects) which will underscore the awe-inspiring significance of each twist and turn of your ever-branching multiverse. If you're a believer in the "Many Worlds" interpretation of quantum behavior, this app is a must. And if you're not, just think of this as THE most random of all coin-flip apps -- in that it uses the most random event in the universe: a single quantum event! *According to prevailing quantum theory. Universes cannot contact each other. Not responsible for user's actions. ©Copyright 2009 Eric Daniels - All Rights Reserved

About

Countdown Star (Ad

Track time until or since important events with customizable timers. Set up countdowns for birthdays, holidays, and vacations, or count up from anniversaries and special dates. Share your event timers with friends and family.

Highlights
  • Add custom events
  • Customize event visuals
  • Apple Watch display
  • Today Widget integration
  • Set exact event times
  • Adjust time units
  • Share event timers
Features
Read full description

Countdown Star is the best way to countdown to — and count up from — all of your favorite events. Countdown to birthdays, holidays, an upcoming vacation, a wedding, the New Year, parties, sporting events, concerts and more. Count up from anniversaries, the day you were born, and other special events in the past. * How many seconds until your next birthday? * How many months since you were born? * How many days until you graduate from college? * How many hours until your anniversary? * How much time is left until your vacation starts? * How many days until Christmas? * How many minutes until your party begins? * How much time is left until your baby's due date? Countdown Star is the countdown app that lets you choose which events to add, then keeps them in sync across all of your devices. Features: * iCloud Sync — events and wallpapers sync automatically across all your iPhone, iPad, and Apple Watch devices * Celebration Animations — choose Confetti, Fireworks, Balloons, Stars, or Lasers when your countdown reaches zero * Repeating Events — annual events automatically advance to the next year so you never have to update them * Home Screen Widgets — Small, Medium, and Large widgets let you glance at your countdowns without opening the app * Apple Watch — view your events right on your wrist * Add Your Own Events — add as many events as you like * Custom Wallpapers — choose from 15+ built-in wallpapers or use your own photos * Time Zone Support — set each event in any time zone with localized city names * Sort and Search — sort by date, title, or your own custom order; events are sectioned into Countdown and Count Up groups * Favorites and Notifications — mark events as favorites to receive a notification when their countdown reaches zero * Interactive Slider — instantly switch between seconds, minutes, hours, days, weeks, months, or years to see your countdown exactly how you want it * Customizable Timer — choose timer position (Top, Middle, or Bottom), show or hide weeks, and toggle the leading zero * Multiple App Icons — personalize the app icon on your Home Screen Note: Countdown Star is available as a free version (with ads and an optional Remove Ads purchase) and as a paid ad-free version.

Screenshots

Universe Splitter4 screens
Countdown Star (Ad4 screens

Verdict

The call

The clearest difference is update cadence: Countdown Star (Ad at every 2 weeks against Universe Splitter's every 17 months. Universe Splitter's advantage is review sentiment (76% vs 56%) and chart position (#13 vs unranked). 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

Universe Splitter costs $1.99 and Countdown Star (Ad $1.99 up front. Neither carries in-app purchases, so what you see is what you pay.

ReceptionRating · Positive reviews · Number of ratings

On the App Store both sit at effectively the same score — 4.7 for Universe Splitter against 4.7 for Countdown Star (Ad. Both are backed by a comparable volume of ratings — 1.5K and 3.7K respectively. Written reviews are what separate them: 76% of Universe Splitter's written reviews are positive against 56% of Countdown Star (Ad's.

UpkeepUpdate frequency

Universe Splitter ships an update every 17 months, Countdown Star (Ad every 2 weeks. The most recent releases landed on October 31, 2026 and November 1, 2026 respectively.

Scorecard4 real differences · 7 level
Universe Splitter versus Countdown Star (Ad: the parameters behind the verdict, then further details
ParameterUniverse SplitterCountdown Star (Ad
Price$1.99$1.99
Rating4.7 (1.5K ratings)4.7 (3.7K ratings) — better
Positive reviews75.6% of reviews — better55.8% of reviews
Number of ratings1.5K3.7K — better
Update frequencyEvery 17 monthsEvery 2 weeks — better
AdsNoNo
In-app purchasesNoNo
MonetizationPaidPaid
Best chart rank#13 — better—
DevicesiPhone, iPad, iPodiPhone, iPad, Apple Watch
Requires iOS15.6 — better17.0
Further details — not scored
Size104 MB53 MB
Age rating4+4+
DeveloperAerfish LLCJoseph Merrill

Customer experience

Universe Splitter

All ratings1,527 ratings
Positive91.4%
Neutral2.9%
Negative5.8%
Written reviews205 reviews
Positive75.6%
Neutral6.3%
Negative18.0%

Countdown Star (Ad

All ratings3,702 ratings
Positive93.4%
Neutral3.0%
Negative3.6%
Written reviews405 reviews
Positive55.8%
Neutral15.6%
Negative28.6%

User reviews

Universe Splitter

From 1.5K App Store ratings

What we love

  • 👍 Great app for decision-making
  • 🤖 Unique concept using quantum mechanics
  • 🤩 Fun and engaging user experience
  • 🧠 Helps with indecision and analysis paralysis

Room to improve

  • 🐛 Inconsistent or unreliable results
  • 🔧 Technical issues with connectivity or functionality
  • 💤 Boring or repetitive after repeated use
  • 🤔 Doubts about the app's true quantum capabilities

Countdown Star (Ad

From 3.7K App Store ratings

What we love

  • 👍 Easy to use
  • 💡 Customizable backgrounds
  • 🚀 Simple and functional
  • 🎨 Nice visual design

Room to improve

  • 🐛 Unreliable widget functionality
  • 🔍 Limited event management options
  • 💰 Paid version doesn't import free version data
  • 🔧 Lack of customization options

Bugs and requests

Universe Splitter

Reported bugs

3 issues
  • App crashes or freezes during use
  • Inconsistent behavior across devices or OS versions
  • Issues with loading or connecting to the quantum device

Requested features

4 requests
  • Add ability to track and review past decisions
  • Improve visual design and user interface
  • Provide more information on the science behind the app
  • Allow customization of options and decision-making process

Countdown Star (Ad

Reported bugs

4 issues
  • Custom wallpapers not saving
  • Countdown not updating correctly
  • Compatibility issues with newer iOS versions
  • Notification system not working as expected

Requested features

5 requests
  • Recurring event support
  • Ability to exclude weekends/holidays from countdown
  • Multiple event display on main screen
  • Improved widget functionality
  • Sync across devices

In-app purchases

None

Universe Splitter

No in-app purchases

None

Countdown Star (Ad

No in-app purchases

Questions

Is Universe Splitter free?
Universe Splitter costs $1.99, with no in-app purchases.
Is Countdown Star (Ad free?
Countdown Star (Ad costs $1.99, with no in-app purchases.
Which has better reviews, Universe Splitter or Countdown Star (Ad?
Countdown Star (Ad is rated higher. Universe Splitter averages 4.7 out of 5 from 1.5K ratings, while Countdown Star (Ad averages 4.7 from 3.7K ratings.
Do Universe Splitter or Countdown Star (Ad have ads?
Neither Universe Splitter nor Countdown Star (Ad shows ads.
Which is updated more often, Universe Splitter or Countdown Star (Ad?
Universe Splitter ships an update every 17 months, and Countdown Star (Ad every 2 weeks. Most recently, Universe Splitter was updated on October 31, 2026 and Countdown Star (Ad on November 1, 2026.

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