# Transformer Calculator Plus vs Voltage Drop Pro

The clearest difference is update cadence: Voltage Drop Pro at every 2 months against Transformer Calculator Plus's every 45 months. Transformer Calculator Plus's advantage is price ($2.99 vs $3.99) and iOS requirement (13.0 vs 17.5). On ads, in-app purchases and device support there is nothing between them.

Transformer Calculator Plus costs $2.99 and Voltage Drop Pro $3.99 up front. Neither carries in-app purchases, so what you see is what you pay.

Transformer Calculator Plus ships an update every 45 months, Voltage Drop Pro every 2 months. The most recent releases landed on September 10, 2026 and July 9, 2026 respectively.

## The numbers

| Metric | Transformer Calculator Plus | Voltage Drop Pro |
| --- | --- | --- |
| Price | **$2.99** | $3.99 |
| Rating | **[3.3 (4 ratings)](https://appshunter.io/ios/app/transformer-calculator-plus/id1372528401/reviews)** | — |
| Number of ratings | **4** | — |
| Positive reviews | 0.0% of reviews | — |
| In-app purchases | No | No |
| Ads | No | No |
| Update frequency | Every 45 months | **Every 2 months** |
| Monetization | Paid | — |
| Size | 1 MB | 15 MB |
| Requires iOS | **13.0** | 17.5 |
| Devices | **iPhone, iPad, iPod** | iPhone, iPad |
| Age rating | 4+ | 4+ |
| Developer | [Nitrio](https://appshunter.io/developer/321121189) | [Snappy Appz Inc.](https://appshunter.io/developer/375591377) |

## What reviewers say

### Transformer Calculator Plus

[App page](https://appshunter.io/ios/app/transformer-calculator-plus/id1372528401)

This utility app calculates key parameters for transformers, including voltage, current, and turns ratio. It helps determine if a transformer is step-up or step-down, essential for power conversion applications.

**Highlights:** Calculate primary and secondary voltage, Calculate primary and secondary current, Calculate transformer turns ratio, Determine step-up or step-down transformer, Supports AC voltage calculations

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

**In-app purchases:** none


### Voltage Drop Pro

[App page](https://appshunter.io/ios/app/voltage-drop-pro/id1601052433)

**Features:** macOS Compatibility

**In-app purchases:** none


## Frequently asked questions

### Is Transformer Calculator Plus free?

Transformer Calculator Plus costs $2.99, with no in-app purchases.

### Is Voltage Drop Pro free?

Voltage Drop Pro costs $3.99, with no in-app purchases.

### Do Transformer Calculator Plus or Voltage Drop Pro have ads?

Neither Transformer Calculator Plus nor Voltage Drop Pro shows ads.

### Which is updated more often, Transformer Calculator Plus or Voltage Drop Pro?

Transformer Calculator Plus ships an update every 45 months, and Voltage Drop Pro every 2 months. Most recently, Transformer Calculator Plus was updated on September 10, 2026 and Voltage Drop Pro on July 9, 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.*