# Duct Calculator Elite vs Ctrldoc

The clearest difference is price: Ctrldoc at Free against Duct Calculator Elite's $9.99. Ctrldoc also leads on update cadence (every 4 weeks vs every 15 months) and iOS requirement (12.0 vs 15.6). Duct Calculator Elite's advantage is chart position (#193 vs unranked). On ads, in-app purchases and device support there is nothing between them.

Ctrldoc is free to download; Duct Calculator Elite costs $9.99 up front. Neither carries in-app purchases, so what you see is what you pay.

Duct Calculator Elite ships an update every 15 months, Ctrldoc every 4 weeks. The most recent releases landed on September 23, 2026 and December 2, 2025 respectively.

## The numbers

| Metric | Duct Calculator Elite | Ctrldoc |
| --- | --- | --- |
| Price | $9.99 | **Free** |
| Rating | **[4.8 (232 ratings)](https://appshunter.io/ios/app/duct-calculator-elite/id665701601/reviews)** | — |
| Number of ratings | **232** | — |
| Positive reviews | 50.0% of reviews | — |
| In-app purchases | No | No |
| Ads | No | No |
| Update frequency | Every 15 months | **Every 4 weeks** |
| Monetization | Paid | — |
| Best chart rank | **#193** | — |
| Size | 13 MB | 128 MB |
| Requires iOS | 15.6 | **12.0** |
| Devices | iPhone, iPad, iPod | iPhone, iPad, iPod |
| Age rating | 4+ | 4+ |
| Developer | [Cyberprodigy LLC](https://appshunter.io/developer/510284906) | [Lattech Pty Ltd](https://appshunter.io/developer/1577327477) |

## What reviewers say

### Duct Calculator Elite

[App page](https://appshunter.io/ios/app/duct-calculator-elite/id665701601)

**Currently charting:** #193 Top Paid · Utilities (US App Store)

This app simplifies HVAC duct sizing calculations. It computes duct size, velocity, pressure drop, and flow rate with an intuitive interface. Supports various units and duct materials for precise HVAC design.

**Highlights:** Calculate duct size, velocity, pressure drop, flow rate, Duct Size by Airflow mode, Duct Size by Dimension mode, Pressure Drop calculations, Customizable units and duct materials, Uses ASHRAE Handbook friction loss equations

**Features:** macOS Compatibility

**In-app purchases:** none


### Ctrldoc

[App page](https://appshunter.io/ios/app/ctrldoc/id1461731308)

**Features:** macOS Compatibility

**In-app purchases:** none


## Frequently asked questions

### Is Duct Calculator Elite free?

Duct Calculator Elite costs $9.99, with no in-app purchases.

### Is Ctrldoc free?

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

### Do Duct Calculator Elite or Ctrldoc have ads?

Neither Duct Calculator Elite nor Ctrldoc shows ads.

### Which is updated more often, Duct Calculator Elite or Ctrldoc?

Duct Calculator Elite ships an update every 15 months, and Ctrldoc every 4 weeks. Most recently, Duct Calculator Elite was updated on September 23, 2026 and Ctrldoc on December 2, 2025.

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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.*