Comparison

Retime vs 相対性理論計

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

Head to head
About

Retime

This app helps serious learners manage their study time and track progress. It combines a timer, task management, and analytics to visualize daily efforts and ensure goals are met. Features include goal setting, exam countdowns, and app blocking to enhance focus.

Highlights
  • Unified task management and timer
  • Study goal progress tracking
  • Exam countdown and score tracking
  • Distracting app blocking
  • Pomodoro and count-up timer modes
  • Study time visualization
  • Customizable subjects and themes
Features
Read full description

You're studying hard, but can't see any progress. You make a plan, but somehow it always falls apart. That feeling of "working hard but getting nowhere" — Retime changes that. Retime is a study management app for serious learners, bringing together a timer, task management, and learning analytics in one place. "Plan → Focus → Record → Analyze" Complete this entire cycle in a single app. Your daily efforts become visible through graphs and numbers. Students preparing for exams, professionals studying for certifications, language learners, building a reading habit—— Retime is here for anyone who is serious about reaching their goals. Feature ① Task Management and Timer, Unified ・Manage daily tasks with a weekly calendar. Swipe smoothly between weeks ・Link tasks to your timer to accurately record what you studied and for how long ・Set up recurring tasks to automatically create your daily study routine ・Drag and drop to reschedule tasks with ease ・One glance at your to-do list tells you exactly what to study today Feature ② Track Whether You're On Pace with Study Goals ・Set concrete goals like "finish 300 pages of this textbook by [date]" ・Automatically compare your recommended daily pace against your actual progress ・A predicted completion date is always shown, so you know at a glance whether you'll make it in time ・Manage multiple goals simultaneously — exam prep, certifications, reading, and more Feature ③ Exam Countdown & Mock Exam Score Tracking ・Register your exam dates and see remaining days updated in real time ・Log your mock exam and practice test scores by subject ・Visualize your score trends with charts to see how much you've improved Feature ④ Block Distracting Apps During Study Sessions ・Block apps like social media, YouTube, and games while you study ・Effective for breaking phone addiction ・Blocking is active only while the timer is running, so the quality of your study time goes up Feature ⑤ Two Timer Modes: Pomodoro & Count-Up ・Use the Pomodoro timer to alternate between focused work and breaks, maximizing productivity ・Use the count-up timer to freely measure and log your study time ・Supports Dynamic Island and Lock Screen Live Activity — always keep an eye on your timer ・Check today's study time at a glance with the home screen widget ・Stay focused with background sounds like alpha waves, brown noise, rain, and ocean waves Feature ⑥ Visualize Study Time to Stay Motivated ・View weekly and monthly study time trends in graph form ・See a subject-by-subject breakdown to understand where your time is going ・Browse your full session history in a timeline view ・Watching your efforts pile up keeps the motivation going Feature ⑦ Customize to Make It Yours ・Set your own subject names and colors ・Change the app's theme color to match your style Suitable for every learning scenario — students, professionals studying for certifications, language learners, and anyone building a reading habit. Start recording a little every day, and keep moving toward your goal.

About

相対性理論計

Features
Read full description

Instead of a pedometer — Einstein’s “time drift.” A grand thought experiment (Gedankenexperiment) you can carry in your pocket. The formulas are real. The measuring is rough GPS. Walk. Take the train. Climb the stairs. Just living as usual already opens a tiny gap between you and “the you who stayed where you woke this morning.” Relativity Meter is an everyday toy for peeking at that stretch and squeeze of time hidden in a day’s steps — blown up to the absurd scale of × 10⁻¹⁴ seconds. • Blue = time slows (speed: special relativity) • Red = time advances (height: gravitational redshift) • The number on the home screen = today’s net drift from both We use Einstein’s equations as they are: Δt ≈ t·v²/(2c²) from special relativity (speed), and Δt ≈ t·gh/c² from general relativity — gravitational redshift (height). The sensor side is phone GPS. Not a lab instrument — a toy for finding wonder in ordinary steps. Privacy you can trust No account. Fully offline. Location is computed on-device only and is never sent to any server. (On Apple Watch, you can glance at today’s number on your wrist.) Optional dial-face pack The digital dial stays free. SF and cosmic dials include a 7-day on-device trial, then unlock with one non-consumable purchase (not a subscription). Made by Lagado Lab.

Screenshots

Retime4 screens
相対性理論計4 screens

Verdict

The call

The clearest difference is in-app purchases: 相対性理論計 at none against Retime's 3. 相対性理論計 also leads on ads (none vs shown) and update cadence (daily vs every 5 days). On price, 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

Both are free to download. Retime sells 3 in-app purchases, starting at $1.99 per month. 相対性理論計 asks for nothing beyond the download.

UpkeepUpdate frequency

Retime ships an update every 5 days, 相対性理論計 daily. The most recent releases landed on October 23, 2026 and October 13, 2026 respectively.

Scorecard3 real differences · 7 level
Retime versus 相対性理論計: the parameters behind the verdict, then further details
ParameterRetime相対性理論計
PriceFreeFree
Rating5.0 (1 ratings) — better—
Positive reviews72.2% of reviews—
Number of ratings1 — better—
Update frequencyEvery 5 daysDaily — better
AdsYesNo — better
In-app purchasesYesNo — better
MonetizationFree with in-app purchases—
DevicesiPhone, iPadiPhone, Apple Watch
Requires iOS17.017.0
Further details — not scored
Size30 MB8 MB
Age rating4+4+
DeveloperRyo IidaTAKEHITO AWASHIMA

In-app purchases

3 purchases

Retime

Subscriptions3
  • リタイム PRO 1ヶ月$1.991 Month
  • リタイム PRO 1年間$14.991 Year
  • リタイム PRO 1年間 キャンペーン1 Year trial$19.991 Year
None

相対性理論計

No in-app purchases

Questions

Is Retime free?
Retime is free to download, with in-app purchases available.
Is 相対性理論計 free?
相対性理論計 is free to download, with no in-app purchases.
Do Retime or 相対性理論計 have ads?
Retime shows ads; 相対性理論計 does not.
Which is updated more often, Retime or 相対性理論計?
Retime ships an update every 5 days, and 相対性理論計 daily. Most recently, Retime was updated on October 23, 2026 and 相対性理論計 on October 13, 2026.

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