# DropTubeBuilder vs HydroCalc Basic

The clearest difference is update cadence: HydroCalc Basic at every 11 days against DropTubeBuilder's monthly. On price, ads, in-app purchases and device support there is nothing between them.

Both are free to download. DropTubeBuilder sells 2 in-app purchases, starting at $4.99 per month and HydroCalc Basic sells 1 one-off in-app purchase. Whichever you choose, the download price is not the number that matters.

DropTubeBuilder ships an update monthly, HydroCalc Basic every 11 days. The most recent releases landed on October 13, 2026 and October 4, 2026 respectively.

## The numbers

| Metric | DropTubeBuilder | HydroCalc Basic |
| --- | --- | --- |
| Price | Free | Free |
| Rating | **[5.0 (6 ratings)](https://appshunter.io/ios/app/droptubebuilder-fuel-tanks/id6740597739/reviews)** | — |
| Number of ratings | **6** | — |
| Positive reviews | 100.0% of reviews | — |
| In-app purchases | Yes | Yes |
| Ads | No | No |
| Update frequency | Monthly | **Every 11 days** |
| Monetization | Free with in-app purchases | — |
| Size | 2 MB | 35 MB |
| Requires iOS | 16.6 | **15.1** |
| Devices | iPhone, iPad | **iPhone, iPad, iPod** |
| Age rating | 4+ | 4+ |
| Developer | [Chris Thrasher](https://appshunter.io/developer/1790762521) | [Transparent Blue Water LLC](https://appshunter.io/developer/1847968351) |

## What reviewers say

### DropTubeBuilder

[App page](https://appshunter.io/ios/app/droptubebuilder-fuel-tanks/id6740597739)

This tool simplifies fuel system measurements for technicians. It offers accurate drop tube calculations, supports precise fill levels, and provides a reference for dispenser error codes. Streamline your work and ensure regulatory compliance in the field.

**Highlights:** Accurate drop tube length calculations, 95% fill level support, Tank volume chart builder, Dispenser error code reference, User-friendly field interface

**Features:** macOS Compatibility

**In-app purchases (2)**

| Purchase | Price | Billing |
| --- | --- | --- |
| DropTubeBuilder Pro monthly | $4.99 | per month |
| DropTube Pro Annual | $24.99 | per year |


### 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 |
| --- | --- | --- |
| Premium - Flow Units & Ad-Free | $1.99 | one-time |


## Frequently asked questions

### Is DropTubeBuilder free?

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

### Is HydroCalc Basic free?

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

### Do DropTubeBuilder or HydroCalc Basic have ads?

Neither DropTubeBuilder nor HydroCalc Basic shows ads.

### Which is updated more often, DropTubeBuilder or HydroCalc Basic?

DropTubeBuilder ships an update monthly, and HydroCalc Basic every 11 days. Most recently, DropTubeBuilder was updated on October 13, 2026 and HydroCalc Basic on October 4, 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.*