# Keystone Pump TDH Calculator vs HydroCalc Basic

The clearest difference is in-app purchases: Keystone Pump TDH Calculator at none against HydroCalc Basic's 1. HydroCalc Basic's advantage is update cadence (every 11 days vs every 6 months) and device support (3 vs 1). On price and ads there is nothing between them.

Both are free to download. HydroCalc Basic sells 1 one-off in-app purchase. Keystone Pump TDH Calculator asks for nothing beyond the download.

Keystone Pump TDH Calculator ships an update every 6 months, HydroCalc Basic every 11 days. The most recent releases landed on October 16, 2026 and October 29, 2026 respectively.

## The numbers

| Metric | Keystone Pump TDH Calculator | HydroCalc Basic |
| --- | --- | --- |
| Price | Free | Free |
| Rating | **[5.0 (1 ratings)](https://appshunter.io/ios/app/keystone-pump-tdh-calculator/id880925443/reviews)** | — |
| Number of ratings | **1** | — |
| Positive reviews | 100.0% of reviews | — |
| In-app purchases | **No** | Yes |
| Ads | No | No |
| Update frequency | Every 6 months | **Every 11 days** |
| Monetization | Free | — |
| Size | 3 MB | 35 MB |
| Requires iOS | 17.6 | **15.1** |
| Devices | iPhone | **iPhone, iPad, iPod** |
| Age rating | 4+ | 4+ |
| Developer | [Keystone Pumps LTD](https://appshunter.io/developer/435839301) | [Transparent Blue Water LLC](https://appshunter.io/developer/1847968351) |

## What reviewers say

### Keystone Pump TDH Calculator

[App page](https://appshunter.io/ios/app/keystone-pump-tdh-calculator/id880925443)

This utility app assists engineers and technical personnel in calculating system parameters for slurry pipe and pump sizing. It computes required head pressure and limiting settling velocity based on user-inputted system data. The tool aims to simplify the selection process for slurry pumps.

**Highlights:** Slurry Density Calculation, Limiting Settling Velocity Calculation, Slurry Head & Equivalent Water Head Calculation, Pipe Type and Size Database, NPSHA Calculation, US and Metric Units, Save Calculation Results

**Features:** macOS Compatibility

**In-app purchases:** none


### HydroCalc Basic

[App page](https://appshunter.io/ios/app/hydrocalc-basic/id6752577110)

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

**In-app purchases (1)**

| Purchase | Price | Billing |
| --- | --- | --- |
| Pro Pack | $5.99 | one-time |


## Frequently asked questions

### Is Keystone Pump TDH Calculator free?

Keystone Pump TDH Calculator is free to download, with no in-app purchases.

### Is HydroCalc Basic free?

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

### Do Keystone Pump TDH Calculator or HydroCalc Basic have ads?

Neither Keystone Pump TDH Calculator nor HydroCalc Basic shows ads.

### Which is updated more often, Keystone Pump TDH Calculator or HydroCalc Basic?

Keystone Pump TDH Calculator ships an update every 6 months, and HydroCalc Basic every 11 days. Most recently, Keystone Pump TDH Calculator was updated on October 16, 2026 and HydroCalc Basic on October 29, 2026.

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