# SPIDERPLUS for iPhone vs Duct

The clearest difference is update cadence: SPIDERPLUS for iPhone at every 5 weeks against Duct's every 16 months. Duct's advantage is device support (3 vs 1) and iOS requirement (11.4 vs 17.0). On price, ads and in-app purchases there is nothing between them.

Both are free to download. Neither carries in-app purchases, so what you see is what you pay.

SPIDERPLUS for iPhone ships an update every 5 weeks, Duct every 16 months. The most recent releases landed on September 20, 2026 and October 6, 2026 respectively.

## The numbers

| Metric | SPIDERPLUS for iPhone | Duct |
| --- | --- | --- |
| Price | Free | Free |
| Positive reviews | — | 100.0% of reviews |
| In-app purchases | No | No |
| Ads | No | No |
| Update frequency | **Every 5 weeks** | Every 16 months |
| Monetization | — | Free |
| Size | 54 MB | 3 MB |
| Requires iOS | 17.0 | **11.4** |
| Devices | iPhone | **iPhone, iPad, iPod** |
| Age rating | 4+ | 4+ |
| Developer | [SpiderPlus & Co.](https://appshunter.io/developer/452916604) | [Izumi Consulting,Inc.](https://appshunter.io/developer/735908925) |

## What reviewers say

### SPIDERPLUS for iPhone

[App page](https://appshunter.io/ios/app/spiderplus-for-iphone/id479875792)

**Features:** macOS Compatibility

**In-app purchases:** none


### Duct

[App page](https://appshunter.io/ios/app/duct-fit/id735908922)

This application simplifies the selection of duct sizes using intuitive design and simple operations. It calculates appropriate duct sizes based on airflow, standard static pressure, and air velocity, supporting both rectangular and round ducts.

**Highlights:** Intuitive design for easy duct size selection, Calculates duct size based on airflow, static pressure, and velocity, Supports both rectangular and round ducts, Visual representation of selected duct shapes, Customizable warning and upper limits for aspect ratio and air velocity, Set default standard static pressure

**Features:** macOS Compatibility

**In-app purchases:** none


## Frequently asked questions

### Is SPIDERPLUS for iPhone free?

SPIDERPLUS for iPhone is free to download, with no in-app purchases.

### Is Duct free?

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

### Do SPIDERPLUS for iPhone or Duct have ads?

Neither SPIDERPLUS for iPhone nor Duct shows ads.

### Which is updated more often, SPIDERPLUS for iPhone or Duct?

SPIDERPLUS for iPhone ships an update every 5 weeks, and Duct every 16 months. Most recently, SPIDERPLUS for iPhone was updated on September 20, 2026 and Duct on October 6, 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.*