# HydroCalc Plus vs Kapy

The clearest difference is price: Kapy at Free against HydroCalc Plus's $6.99. HydroCalc Plus's advantage is in-app purchases (none vs 3) and iOS requirement (15.1 vs 26.2). On rating, review sentiment, ratings volume and update cadence there is nothing between them.

Kapy is free to download; HydroCalc Plus costs $6.99 up front. Kapy sells 3 in-app purchases, starting at $1.99 per month. HydroCalc Plus asks for nothing beyond the download.

On the App Store both sit at effectively the same score — 5.0 for HydroCalc Plus against 5.0 for Kapy. Both are backed by a comparable volume of ratings — 1 and 2 respectively. Written reviews split almost evenly too, at 100% and 100% positive.

HydroCalc Plus ships an update every 3 weeks, Kapy fortnightly. The most recent releases landed on November 1, 2026 and November 5, 2026 respectively.

## The numbers

| Metric | HydroCalc Plus | Kapy |
| --- | --- | --- |
| Price | $6.99 | **Free** |
| Rating | [5.0 (1 ratings)](https://appshunter.io/ios/app/hydrocalc-plus/id578807688/reviews) | [5.0 (2 ratings)](https://appshunter.io/ios/app/kapy-cozy-habit-tracker/id6748405563/reviews) |
| Number of ratings | 1 | **2** |
| Positive reviews | 100.0% of reviews | 100.0% of reviews |
| In-app purchases | **No** | Yes |
| Ads | No | No |
| Update frequency | Every 3 weeks | **Fortnightly** |
| Monetization | Paid | **Freemium** |
| Size | 34 MB | 69 MB |
| Requires iOS | **15.1** | 26.2 |
| Devices | **iPhone, iPad, iPod** | iPhone, iPad |
| Age rating | 4+ | 4+ |
| Developer | [Transparent Blue Water LLC](https://appshunter.io/developer/1847968351) | [David Manso](https://appshunter.io/developer/1645844109) |

## What reviewers say

### HydroCalc Plus

[App page](https://appshunter.io/ios/app/hydrocalc-plus/id578807688)

A professional tool for hydraulic engineers to calculate pressure losses in piping systems. It supports US and SI units, offers an extensive pipe material and fittings database, and includes inverse calculations for design optimization.

**Highlights:** Friction head loss calculation (Hazen-Williams), US and SI unit support, Extensive pipe material library, Fittings and valves database, Inverse calculation mode, Real-time results (velocity, losses)

**Features:** macOS Compatibility, Vision Pro support

**In-app purchases:** none


### Kapy

[App page](https://appshunter.io/ios/app/kapy-cozy-habit-tracker/id6748405563)

Build daily routines with gentle encouragement from a virtual capybara. Track habits with simple check-ins or goal-based measurements, and visualize progress with a unique quilt. Share habits with friends and family for mutual motivation.

**Highlights:** Gentle habit tracking with capybara encouragement, Flexible habit scheduling (daily, specific days, weekly), Goal tracking by quantity (glasses, minutes, pages), Progress visualization through a 'quilt' feature, Group habit sharing with up to 6 people, Home and Lock Screen widgets, Customizable color themes

**Features:** macOS Compatibility, Vision Pro support

**In-app purchases (3)**

| Purchase | Price | Billing |
| --- | --- | --- |
| Kapy PRO Monthly | $1.99 | per month |
| Kapy PRO Yearly | $6.99 | per year |
| Kapy PRO Lifetime | $3.99 | one-time |


## Frequently asked questions

### Is HydroCalc Plus free?

HydroCalc Plus costs $6.99, with no in-app purchases.

### Is Kapy free?

Kapy is free to download, with in-app purchases available.

### Which has better reviews, HydroCalc Plus or Kapy?

HydroCalc Plus and Kapy are both rated 5.0 out of 5 on the App Store, from 1 and 2 ratings respectively.

### Do HydroCalc Plus or Kapy have ads?

Neither HydroCalc Plus nor Kapy shows ads.

### Which is updated more often, HydroCalc Plus or Kapy?

HydroCalc Plus ships an update every 3 weeks, and Kapy fortnightly. Most recently, HydroCalc Plus was updated on November 1, 2026 and Kapy on November 5, 2026.

---

*Compared by [AppsHunter](https://appshunter.io/) from daily US App Store data. Review summaries are generated from verbatim App Store reviews.*