Void vs HeartCalc
Price, ratings, monetisation and update history for both apps, side by side — with what reviewers say about each.
Void
This app offers a minimalist approach to meditation with a large, clear timer. It includes optional session timers, interval bells, and ambient sounds. Track your meditation streaks and sync sessions with your health data.
- Large, clear meditation timer
- Optional session timer and interval bells
- Ambient sounds for focus
- Streak tracking for consistency
- Syncs with Health app
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Void is the perfect meditation timer for people who don't want their meditation timer to do too much. Features: • A big, beautiful timer • Optional session timer and interval bells • Ambient sounds to drown out your tinnitus • Streak tracking (for the competitive meditators) • Logs your meditation sessions to the Health app
HeartCalc
Calculate your optimal heart rate training zones using 8 proven formulas. Get personalized zone recommendations for warm-up, fat burn, aerobic, anaerobic, and VO₂ max activities. Train smarter with science-backed insights for maximum fitness results.
- 8 proven heart rate formulas
- Personalized training zones
- Instant calculations
- Detailed explanations
- Automatic data saving
- Clean interface
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Transform Your Training with Precision Heart Rate Zones! Unlock your fitness potential with the most comprehensive heart rate calculator on the App Store. Whether you're a weekend warrior or elite athlete, discover your optimal training intensity for maximum results. 8 PROVEN FORMULAS - Sally Edwards & Winfried Spanaus - Classic Fox & Haskell formula - Modern Tanaka & Gellish methods - Latest Nes research (2013) - Gender-specific Gulati & Miller formulas COMPLETE TRAINING ZONES Get personalized heart rate zones instantly: - Warm-up Zone (50-60%) - Recovery & preparation - Fat Burn Zone (60-70%) - Optimal fat burning - Aerobic Zone (70-80%) - Endurance building - Anaerobic Zone (80-90%) - Performance improvement - VO₂ Max Zone (90-100%) - Peak athletic performance KEY FEATURES - Clean, modern interface following Apple design guidelines - Instant calculations with detailed explanations - Automatic data saving - your age and weight remembered - Multiple language support - No ads, no subscriptions, no data collection PERFECT FOR - Runners preparing for marathons - Cyclists optimizing training rides - Gym enthusiasts maximizing workouts - Personal trainers guiding clients - Anyone serious about fitness results Stop guessing your training intensity. Start training smarter with science-backed heart rate zones that deliver real results!
Screenshots
Verdict
The clearest difference is price: Void at Free against HeartCalc's $0.49. Void also leads on ratings volume (3 vs 1). HeartCalc's advantage is update cadence (every 2 months vs every 10 months) and iOS requirement (16.6 vs 18.2). On rating, review sentiment, ads and in-app purchases 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
Void is free to download; HeartCalc costs $0.49 up front. Neither carries in-app purchases, so what you see is what you pay.
On the App Store both sit at effectively the same score — 5.0 for Void against 5.0 for HeartCalc. Both are backed by a comparable volume of ratings — 3 and 1 respectively. Written reviews split almost evenly too, at 100% and 100% positive.
Void ships an update every 10 months, HeartCalc every 2 months. The most recent releases landed on September 17, 2026 and September 9, 2026 respectively.
| Parameter | Void | HeartCalc |
|---|---|---|
| Price | Free — better | $0.49 |
| Rating | 5.0 (3 ratings) | 5.0 (1 ratings) |
| Positive reviews | 100.0% of reviews | 100.0% of reviews |
| Number of ratings | 3 — better | 1 |
| Update frequency | Every 10 months | Every 2 months — better |
| Ads | No | No |
| In-app purchases | No | No |
| Monetization | Free — better | Paid |
| Devices | iPhone | iPhone |
| Requires iOS | 18.2 | 16.6 — better |
| Further details — not scored | ||
| Size | 32 MB | 1 MB |
| Age rating | 4+ | 12+ |
| Developer | Christopher Langton | Florian Schimanke |
Customer experience
Void
HeartCalc
In-app purchases
Void
No in-app purchases
HeartCalc
No in-app purchases
