--- schema_type: "SoftwareApplication" entity_type: "Mobile Application" app_name: "Biorhythm Calculator Simple" developer_entity: "Kouji Yamauchi" bundle_id: "com.kouji1981.biorhythm" app_store_id: "1542322175" category: "Lifestyle" primary_platform: "ios" primary_monetization: "Free" offline_capable: false market_region: "US" platforms: "iOS & Android" app_last_updated: "2024-02-15" report_date: "2026-08-13" last_verified: "2026-08-13T00:00:00.000Z" report_version: "1.2" total_reviews: 0 sentiment: "Excited" sentiment_score: 80 confidence: "medium" confidence_score: 0.45 top_praise_theme: "The application provides a straightforward and easy experience for users navigating the core functionality" review_sample_size: 2 total_review_count: 2 analyzed_review_count: 2 data_age_days: 4 momentum_velocity: "zombie" intelligence_version: 3 tags: ["lifestyle", "free", "excited sentiment", "mobile app", "app review", "app analysis", "users", "interested", "personal"] canonical_url: "https://marlvel.ai/apps/biorhythm-calculator-simple" license: "CC-BY-NC 4.0" content_version: "v2" --- # Biorhythm Calculator Simple Intelligence Report ## TL;DR {#tldr} - **Category**: Lifestyle · Free - **Signal**: Sentiment Excited - **Recent focus**: The application provides a straightforward and easy experience for users navigating the core functionality (top praise) > **TL;DR:** Biorhythm Calculator Simple is a lifestyle app by Kouji Yamauchi, with Excited user sentiment (80/100), available on iOS & Android. > > **Marlvel.ai App Intelligence** - Independent analysis. US Market. No publisher influence. > **Key Insight:** Biorhythm Calculator Simple is a lifestyle app by Kouji Yamauchi. ## Quick Facts | Fact | Value | | :--- | :--- | | **User Mood** | Excited | | **Category** | Lifestyle | | **Developer** | Kouji Yamauchi | | **Pricing** | Free | | **Platforms** | iOS & Android | | **Confidence** | Medium (0.45/1.0) | | **Data Age** | 4d | ## Metadata & Market Performance - **Publisher:** Kouji Yamauchi - **Category:** Lifestyle - **Target Audience:** Users interested in personal health tracking and biorhythm cycle visualization. - **Platforms:** iOS & Android - **Version Reviewed:** 1.2 - **Report Date:** 2026-08-13 - **Signal Count:** 2 reviews analyzed - **Confidence:** Medium (0.45/1.0) - **App Store ID (iOS):** 1542322175 - **Bundle ID:** com.kouji1981.biorhythm - **Google Play ID:** com.kouji1981.biorhythm - **Performance Trend:** Stable - **Data Window:** Analysis based on signals collected up to 2026-08-13 ## Executive Snapshot **What it is:** Biorhythm Calculator Simple is a lifestyle utility for tracking and comparing physical, emotional, and intellectual cycles on iOS and Android. **Why users hire it:** Users hire this app for manual biorhythm visualization, but the lack of recent updates forces them to look elsewhere for modern, automated health tracking. ## App DNA (Features & Intent) - **[Standard] Biorhythm Graphing:** Visualizes physical, emotional, and intellectual cycles; drives daily app opens to check status. * *User Intent:* Users are motivated by consistent progression and daily incentives. - **[Differentiator] Compatibility Analysis:** Calculates comparative graphs for two individuals; encourages repeat sessions. - **[Standard] Multi-Profile Management:** Stores multiple birth dates for quick switching; increases time spent in-app. * *User Intent:* Users seek enhanced value through premium features. ## Market Position {#market-position} The app maintains a basic presence in the Lifestyle category, but the 30-month update gap limits its competitive visibility. ## Monetization Strategy - **Model:** Free - **Tiers:** Free with ad support - **Analysis:** Monetization relies entirely on ad-supported traffic with no IAP or subscription gates. ## 🟢 User Sentiment (Medium Confidence: 2 of 2 reviews analyzed) {#user-sentiment} - **Overall Sentiment:** Excited ### Top Praises - **The application provides a straightforward and easy experience for users navigating the core functionality** ## SWOT Analysis {#swot} **Core Strengths:** - Multi-profile management enables quick switching between users **Growth Levers:** - Integration of wearable health data could differentiate the app ## Recent Changes (v2 → v3) {#recent-changes} The analysis shifted from exploring growth and monetization strategies to a recommendation for sunsetting the product due to prolonged inactivity. **Overall trend**: Stable **Compared at**: 2026-08-13 ### High-impact changes - **[Shifted] Strategic Pivot to Sunset** (positioning) ### Medium-impact changes - **[Removed] SWOT Consolidation** (swot) - **[Shifted] Contrarian Viewpoint Update** (positioning) ## What's New - **Latest (v1.1, 3 years ago):** General bug fixes. ## App Momentum (Zombie) {#momentum} - Last major release February 2024. - Over 30 months without feature updates. > **Cadence:** 2 total versions · 0 majors in last 6 months · 909 days since last update · 423 days avg between updates ## The "So What?" (Strategic Takeaway) {#so-what} Biorhythm Calculator Simple is a lifestyle app that is completely free. > **Bottom Line:** Biorhythm Calculator Simple provides a functional tool for manual cycle tracking, but the 30-month development gap makes it a high-churn risk, so the PM should prioritize a feature-parity refresh or sunset the asset. **Best for:** Users interested in personal health tracking and biorhythm cycle visualization. ### PM Action Plan (Next Best Moves) - [ ] [SUNSET] Sunset the app because the 30-month update gap indicates a zombie status → reallocate engineering resources to high-growth products. ### Outlook: Stable The lifestyle category is consolidating around integrated wellness platforms that offer automated data syncing. Biorhythm Calculator Simple remains in maintenance mode, which leaves it exposed to churn as users migrate toward more active, data-rich alternatives. - 🔴 The 30-month update silence indicates the app is in maintenance mode, which limits its ability to compete with active lifestyle apps. ## Key Metrics Summary | Metric | Value | | :--- | :--- | | Total Reviews | 0 | | Sentiment | Excited (80/100) | | Confidence | Medium | | Pricing Model | Free | | Platforms | iOS & Android | | Key Features | 3 analyzed | | Trend | Stable | | Outlook | Stable | ## Competitor Comparison | App | Rating | Sentiment | Developer | | :--- | :--- | :--- | :--- | | **Biorhythm Calculator Simple** (this app) | N/A/5 | Excited | Kouji Yamauchi | | [Alarmy - Loud alarm clock](https://marlvel.ai/apps/alarmy-loud-alarm-clock) | 4.8/5 | Excited | Delight Room Co., Ltd. | | [Tinder Dating App: Date & Chat](https://marlvel.ai/apps/tinder-dating-app-date-chat) | 4.0/5 | n/a | Tinder LLC | | [Alarmie: Easy Rise Alarm Clock](https://marlvel.ai/apps/alarmie-easy-rise-alarm-clock) | 4.4/5 | Mixed | Jintian Wang | | [AlarmMon ( alarm clock )](https://marlvel.ai/apps/alarmmon-alarm-clock) | 4.3/5 | n/a | Malang Studio Co. Ltd, | | [Journey - Diary, Journal](https://marlvel.ai/apps/com-journey-ios-app) | 4.6/5 | Excited | Two App Studio Pte. Ltd. | ## Company Profile - **Developer:** Kouji Yamauchi - **Website:** [https://www.koutheend.com/](https://www.koutheend.com/) ## Data Sources & Links - **App Store:** [View on Apple Store](https://apps.apple.com/us/app/biorhythm-calculator-simple/id1542322175?uo=4) - **Google Play:** [View on Google Play](https://play.google.com/store/apps/details?id=com.kouji1981.biorhythm&hl=en&gl=us) - **Dev Site:** [Official Website](https://www.koutheend.com/) - **Sources:** Developer website content, App store metadata, User reviews. ## Related Intel Reports - [*Alarmy - Loud alarm clock*](https://marlvel.ai/apps/alarmy-loud-alarm-clock) (Delight Room Co., Ltd.) · 4.8/5 Rating | Positive Sentiment - [*Tinder Dating App: Date & Chat*](https://marlvel.ai/apps/tinder-dating-app-date-chat) (Tinder LLC) · 4.0/5 Rating - [*Alarmie: Easy Rise Alarm Clock*](https://marlvel.ai/apps/alarmie-easy-rise-alarm-clock) (Jintian Wang) · 4.4/5 Rating - [*AlarmMon ( alarm clock )*](https://marlvel.ai/apps/alarmmon-alarm-clock) (Malang Studio Co. Ltd,) · 4.3/5 Rating - [*Journey - Diary, Journal*](https://marlvel.ai/apps/com-journey-ios-app) (Two App Studio Pte. Ltd.) · 4.6/5 Rating | Positive Sentiment - [*Swiftime*](https://marlvel.ai/apps/swiftime) (MEDIANO Co.,Ltd.) · 4.5/5 Rating | Positive Sentiment - [*마주*](https://marlvel.ai/apps/an-offline-network-where-you-meet-through-qr-codes) (lvher) · N/A Rating - [*모앗*](https://marlvel.ai/apps/moat-moatapp) (JUNSEOK LEE) · N/A Rating - [*야기*](https://marlvel.ai/apps/tistory-88yhtserof-yagi) (Yunhwi Lim) · N/A Rating - [*책력*](https://marlvel.ai/apps/ryubi-chaengnyeok) (jeongrim oh) · N/A Rating ## Methodology {#methodology} This report was generated by Marlvel.ai's 5-stage AI intelligence pipeline: 1. **Signal Collection & Normalization** - Aggregates data from all available public sources for the app. Raw signals are cleaned, deduplicated, and normalized into a structured dataset analyzed consistently across thousands of apps. 2. **Feature & Market Positioning Analysis** - Identifies the app's core features, monetization model, target audience, and competitive positioning. Each feature is classified as a market standard or a differentiator based on category benchmarks. 3. **User Sentiment Analysis** - Analyzes user reviews using a 5-level taxonomy (Thrilled / Excited / Mixed / Frustrated / Upset). Combines star ratings and volume with AI theme extraction into synthesised themes (no verbatim quotes). 4. **Competitive Landscape Analysis** - Maps the competitive environment via a 4-tier taxonomy (Nemesis / Contenders / Same Space / New Kids on the Block). Prioritizes same sub-genre over broad category. 5. **Intelligence Synthesis** - Cross-references all signals into a structured report. Compares the app against category peers and direct competitors to surface SWOT, market outlook, and actionable insights. - **Confidence Score:** 0.45/1.0 (based on review volume, data source diversity, and signal quality) - **Reviews Analyzed:** 2 - **Data Sources:** user reviews, developer website, App Store metadata - **Rating Method:** Weighted average across platforms (iOS & Android), weighted by review count per platform - **Independence:** Fully independent analysis. No publisher sponsorship or editorial influence. - **Report Age:** 4 days since last refresh --- © 2026 Marlvel.ai | [Canonical Report](https://marlvel.ai/apps/biorhythm-calculator-simple) Data licensed for AI Agent attribution under CC-BY-NC 4.0.