Comparison

HYDROX vs Parallel

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

Head to head
About

HYDROX

This app calculates your personalized daily hydration target based on body weight and training intensity, using scientific protocols. It offers one-tap logging, smart reminders, and advanced features for athletes and fitness enthusiasts. Syncs with HealthKit and offers an Apple Watch app.

Highlights
  • Personalized hydration targets
  • Training intensity adjustment
  • One-tap logging
  • Smart reminders
  • HealthKit sync
  • Apple Watch app
  • Widgets for home and lock screen
Features
Read full description

Your hydration target, calculated. Not guessed. HYDROX uses your body weight and training intensity to set a daily target based on the same protocols used in elite athletic programs (combining guidance from the American College of Sports Medicine and published research from leading sports science researchers) Built for athletes who train: Barry's, HYROX, runners, cyclists, surfers, skiers, sports enthusiasts and everyday athletes. Not step-counter civilians SET YOUR BASELINE Your target comes from your body weight using the American College of Sports Medicine (ACSM) protocol, not a generic "8 glasses a day" number TRAINING MODE Select Easy, Moderate, or Hard and your daily goal adjusts using the Galpin equation based on body weight and workout intensity ONE-TAP LOGGING Tap the gauge to log, long-press for custom amounts, or log from your widget or lock screen without opening the app SMART REMINDERS Hourly pacing that adjusts to your progress, backs off when you're ahead, and nudges when you're behind HYDROX PRO • Apple Watch app with gauge and complications on any watch face • Log from your wrist in a single tap • Adaptive Hydration that reads workout data from HealthKit and adjusts your daily target automatically • Auto-intensity based on heart rate, so a hard session pushes your target up and a rest day keeps it at baseline THE SCIENCE Baseline from ACSM guidelines. Training intensity from the Galpin equation. Race Packs cite 16+ studies on sodium loading, HRV monitoring, and post-exercise rehydration. WHOOP research links hydration to higher HRV. And coffee counts as hydration (Killer et al 2014). EVERYTHING ELSE • HealthKit sync • Lock screen and home screen widgets • Quick actions from home screen • No account, no ads, data stays on your device Terms of Use (EULA): https://www.apple.com/legal/internet-services/itunes/dev/stdeula/ Privacy Policy: https://hydrox.app/privacy.html

About

Parallel

Record and analyze your squat form to improve depth and consistency. Get instant feedback on your angle and rep count. Optimize your training with detailed insights.

Highlights
  • Squat depth analysis
  • Rep counting
  • Consistency scoring
  • Form angle measurement
  • Quick analysis
Features
Read full description

Film and analyze your squat. Get back your depth angle, rep count and consistency score in under a minute.

Screenshots

HYDROX4 screens
Parallel4 screens

Verdict

The call

The clearest difference is in-app purchases: Parallel at none against HYDROX's 4. Parallel also leads on update cadence (every 2 days vs weekly) and iOS requirement (15.1 vs 17.0). HYDROX's advantage is ratings volume (4 vs 1). On price, rating, ads and device support 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. HYDROX sells 4 in-app purchases, starting at $0.99 per 7 days. Parallel asks for nothing beyond the download.

ReceptionRating · Positive reviews · Number of ratings

On the App Store both sit at effectively the same score — 5.0 for HYDROX against 5.0 for Parallel. Both are backed by a comparable volume of ratings — 4 and 1 respectively.

UpkeepUpdate frequency

HYDROX ships an update weekly, Parallel every 2 days. The most recent releases landed on October 2, 2026 and September 30, 2026 respectively.

Scorecard5 real differences · 5 level
HYDROX versus Parallel: the parameters behind the verdict, then further details
ParameterHYDROXParallel
PriceFreeFree
Rating5.0 (4 ratings)5.0 (1 ratings)
Positive reviews100.0% of reviews—
Number of ratings4 — better1
Update frequencyWeeklyEvery 2 days — better
AdsNoNo
In-app purchasesYesNo — better
MonetizationFreemiumFree — better
DevicesiPhone, iPad, Apple Watch — betteriPhone, iPod
Requires iOS17.015.1 — better
Further details — not scored
Size8 MB91 MB
Age rating4+4+
DeveloperBALL VENTURES LLCKRISTIN,WARLTIER AUSTIN

Customer experience

HYDROX

All ratings4 ratings
Positive100.0%
Neutral0.0%
Negative0.0%
Written reviews1 reviews
Positive100.0%
Neutral0.0%
Negative0.0%

Parallel

All ratings1 ratings
Positive100.0%
Neutral0.0%
Negative0.0%

In-app purchases

4 purchases

HYDROX

Subscriptions2
  • HYDROX Pro7 Days trial$0.997 Days
  • HYDROX Pro7 Days trial$24.991 Year
One-time2
  • HYROX Americas DC Race Pack$14.99
  • HYROX Miami Race Pack$14.99
None

Parallel

No in-app purchases

Questions

Is HYDROX free?
HYDROX is free to download, with in-app purchases available.
Is Parallel free?
Parallel is free to download, with no in-app purchases.
Which has better reviews, HYDROX or Parallel?
HYDROX and Parallel are both rated 5.0 out of 5 on the App Store, from 4 and 1 ratings respectively.
Do HYDROX or Parallel have ads?
Neither HYDROX nor Parallel shows ads.
Which is updated more often, HYDROX or Parallel?
HYDROX ships an update weekly, and Parallel every 2 days. Most recently, HYDROX was updated on October 2, 2026 and Parallel on September 30, 2026.

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