Comparison

iRelativity vs Relativity Simulator

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

Head to head
About

iRelativity

Features
Read full description

Every time you move, time passes slightly slower for you than for someone standing still. That's not science fiction — it's special relativity, and it's happening to you right now. iRelativity uses your real GPS speed to calculate exactly how much time dilation you're experiencing. Every trip, every commute, every flight adds a tiny slice of time to your lifetime total. The faster you travel, the more you save. Features • Live time dilation — your phone's GPS feeds real velocity into the Lorentz equation in real time • Lifetime total — watch your accumulated time saved grow across every journey, displayed in the most readable unit from femtoseconds up to seconds • Daily history — a chart of how much time you've saved each day • Global leaderboard — compare your lifetime total with other travellers via Game Center • What-if simulator — drag a slider toward the speed of light and see what time dilation would feel like at 0.9 c • Learn tab — interactive animations of the light clock and Einstein's train thought experiment, with a Lorentz factor calculator The numbers are real. At highway speeds you save about a nanosecond per hour. Board a plane and that climbs to microseconds. The physics is identical to the corrections that keep GPS satellites accurate every day.

About

Relativity Simulator

Features
Read full description

Relativity Simulator is an interactive relativity toolkit built strictly on the axiomatic foundations of modern physics. There is no "hard sci-fi" here — every result traces back to the Lorentz transformation of special relativity or the Einstein field equations of general relativity, and is verified against numerical truth fixtures. 【Real physics, not imagination】 · 20 interactive modules covering core effects from special relativity to black holes, gravitational waves, and curved spacetime; · Each module ships with precise charts, adjustable parameters, and a "Theory Card" with a fully visible derivation chain; · All demo numbers are recomputed locally on your device from real CODATA constants — nothing is fabricated. 【Phenomena you can verify yourself】 · Gravitational time dilation: why clocks run faster up high — ~80 ns/day faster atop Everest, ~38 µs/day faster on GPS satellites; · Twin paradox: fly to 4.22 light-years at 0.8c and the Earth twin ages 10.5 years while the traveler ages only 6.3; · Tidal disruption: why you get stretched into "spaghetti" falling into a black hole — small holes tear you outside the horizon, supermassive ones only after you cross it; · Plus light bending, gravitational lensing, the Schwarzschild horizon, frame dragging, and mass–energy equivalence E=mc². 【Built for learning and teaching】 · Volume-based progression: kinematics → gravitational field → black holes → cosmology → applications; · Bilingual (zh/en) system notes ship with every effect: derivation, physical quantities, and references; · Chinese / English UI follows your system language. 【Privacy first】 The app collects, stores, and transmits no personal data, embeds no third-party SDKs, and runs every computation locally on your device. Whether you are studying, teaching, or simply curious, Relativity Simulator lets you actually run the "invisible spacetime" and watch it.

Screenshots

iRelativity4 screens
Relativity Simulator4 screens

Verdict

The call

iRelativity and Relativity Simulator are too close to call on the numbers: across 5 compared parameters — price, ads, in-app purchases and device support among them — neither pulls far enough ahead to decide it. What separates them is feature set and interface, not measurable difference.

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. Neither carries in-app purchases, so what you see is what you pay.

ScorecardNo meaningful differences
iRelativity versus Relativity Simulator: the parameters behind the verdict, then further details
ParameteriRelativityRelativity Simulator
PriceFreeFree
AdsNoNo
In-app purchasesNoNo
DevicesiPhone, iPadiPhone, iPad
Requires iOS18.617.0 — better
Further details — not scored
Size1 MB15 MB
Age rating4+4+
DeveloperVladimir Kostadinov Stoyanov际 郭

In-app purchases

None

iRelativity

No in-app purchases

None

Relativity Simulator

No in-app purchases

Questions

Is iRelativity free?
iRelativity is free to download, with no in-app purchases.
Is Relativity Simulator free?
Relativity Simulator is free to download, with no in-app purchases.
Do iRelativity or Relativity Simulator have ads?
Neither iRelativity nor Relativity Simulator shows ads.

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