# TBD vs Pipe Pressure drop calculator

The clearest difference is in-app purchases: TBD at none against Pipe Pressure drop calculator's 1. TBD also leads on update cadence (every 5 weeks vs every 3 months). On price, ads, device support and iOS requirement there is nothing between them.

Both are free to download. Pipe Pressure drop calculator sells 1 one-off in-app purchase. TBD asks for nothing beyond the download.

TBD ships an update every 5 weeks, Pipe Pressure drop calculator every 3 months. The most recent releases landed on October 8, 2026 and October 10, 2026 respectively.

## The numbers

| Metric | TBD | Pipe Pressure drop calculator |
| --- | --- | --- |
| Price | Free | Free |
| In-app purchases | **No** | Yes |
| Ads | No | No |
| Update frequency | **Every 5 weeks** | Every 3 months |
| Size | 19 MB | 61 MB |
| Requires iOS | 13.0 | 13.0 |
| Devices | iPhone, iPod | **iPhone, iPad, iPod** |
| Age rating | 4+ | 4+ |
| Developer | [Hangzhou Dashi Wisdom Technology Co., Ltd.](https://appshunter.io/developer/1822219570) | [Ashvin Kevadiya](https://appshunter.io/developer/1756324971) |

## What reviewers say

### TBD

[App page](https://appshunter.io/ios/app/tbd-flowmeter/id1632862012)

**Features:** macOS Compatibility

**In-app purchases:** none


### Pipe Pressure drop calculator

[App page](https://appshunter.io/ios/app/pipe-pressure-drop-calculator/id6752385472)

**Features:** macOS Compatibility

**In-app purchases (1)**

| Purchase | Price | Billing |
| --- | --- | --- |
| Lifetime Premium | $7.99 | one-time |


## Frequently asked questions

### Is TBD free?

TBD is free to download, with no in-app purchases.

### Is Pipe Pressure drop calculator free?

Pipe Pressure drop calculator is free to download, with in-app purchases available.

### Do TBD or Pipe Pressure drop calculator have ads?

Neither TBD nor Pipe Pressure drop calculator shows ads.

### Which is updated more often, TBD or Pipe Pressure drop calculator?

TBD ships an update every 5 weeks, and Pipe Pressure drop calculator every 3 months. Most recently, TBD was updated on October 8, 2026 and Pipe Pressure drop calculator on October 10, 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.*