# Inductor Design Pro vs Transformer Calculation Tool

The clearest difference is iOS requirement: Transformer Calculation Tool at 13.0 against Inductor Design Pro's 15.0. On price, update cadence, ads and in-app purchases there is nothing between them.

Both are free to download. Inductor Design Pro sells 1 in-app purchase, starting at $29.99 per year and Transformer Calculation Tool sells 1 one-off in-app purchase. Whichever you choose, the download price is not the number that matters.

Inductor Design Pro ships an update every 3 weeks, Transformer Calculation Tool every 4 weeks. The most recent releases landed on July 4, 2026 and September 16, 2026 respectively.

## The numbers

| Metric | Inductor Design Pro | Transformer Calculation Tool |
| --- | --- | --- |
| Price | Free | Free |
| In-app purchases | Yes | Yes |
| Ads | No | No |
| Update frequency | **Every 3 weeks** | Every 4 weeks |
| Size | 9 MB | 57 MB |
| Requires iOS | 15.0 | **13.0** |
| Devices | iPhone, iPad, iPod | iPhone, iPad, iPod |
| Age rating | 4+ | 4+ |
| Developer | [建忠 徐](https://appshunter.io/developer/1871049057) | [Shraddhaben Parmar](https://appshunter.io/developer/1889769325) |

## What reviewers say

### Inductor Design Pro

[App page](https://appshunter.io/ios/app/inductor-design-pro/id6758878884)

**In-app purchases (1)**

| Purchase | Price | Billing |
| --- | --- | --- |
| Annual Subscription | $29.99 | per year |


### Transformer Calculation Tool

[App page](https://appshunter.io/ios/app/transformer-calculation-tool/id6772152007)

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

**In-app purchases (1)**

| Purchase | Price | Billing |
| --- | --- | --- |
| Lifetime premium | $9.99 | one-time |


## Frequently asked questions

### Is Inductor Design Pro free?

Inductor Design Pro is free to download, with in-app purchases available.

### Is Transformer Calculation Tool free?

Transformer Calculation Tool is free to download, with in-app purchases available.

### Do Inductor Design Pro or Transformer Calculation Tool have ads?

Neither Inductor Design Pro nor Transformer Calculation Tool shows ads.

### Which is updated more often, Inductor Design Pro or Transformer Calculation Tool?

Inductor Design Pro ships an update every 3 weeks, and Transformer Calculation Tool every 4 weeks. Most recently, Inductor Design Pro was updated on July 4, 2026 and Transformer Calculation Tool on September 16, 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.*