# Simple Pendulum Calculator vs ZEFNET Charge

The clearest difference is price: ZEFNET Charge at Free against Simple Pendulum Calculator's $2.99. ZEFNET Charge also leads on update cadence (every 4 months vs every 31 months) and ratings volume (6 vs 1). Simple Pendulum Calculator's advantage is rating (5.0 vs 2.0). On ads, in-app purchases and device support there is nothing between them.

ZEFNET Charge is free to download; Simple Pendulum Calculator costs $2.99 up front. Neither carries in-app purchases, so what you see is what you pay.

Simple Pendulum Calculator holds the better App Store score, 5.0 against 2.0. That said, the two scores are not equally well evidenced: ZEFNET Charge has 6 ratings behind it against 1, so its average is the more settled of the two.

Simple Pendulum Calculator ships an update every 31 months, ZEFNET Charge every 4 months. The most recent releases landed on September 29, 2026 and October 16, 2026 respectively.

## The numbers

| Metric | Simple Pendulum Calculator | ZEFNET Charge |
| --- | --- | --- |
| Price | $2.99 | **Free** |
| Rating | **[5.0 (1 ratings)](https://appshunter.io/ios/app/simple-pendulum-calculator/id1397285555/reviews)** | [2.0 (6 ratings)](https://appshunter.io/ios/app/zefnet-charge/id1470100874/reviews) |
| Number of ratings | 1 | **6** |
| Positive reviews | — | 10.4% of reviews |
| In-app purchases | No | No |
| Ads | No | No |
| Update frequency | Every 31 months | **Every 4 months** |
| Monetization | Paid | **Free** |
| Size | 1 MB | 19 MB |
| Requires iOS | 13 | **11.0** |
| Devices | **iPhone, iPad, iPod** | iPhone, iPod |
| Age rating | 4+ | 4+ |
| Developer | [Nitrio](https://appshunter.io/developer/321121189) | [ZEF Energy Inc.](https://appshunter.io/developer/1470100873) |

## What reviewers say

### Simple Pendulum Calculator

[App page](https://appshunter.io/ios/app/simple-pendulum-calculator/id1397285555)

This physics calculator quickly computes pendulum period, frequency, maximum height, energy, and speed. It supports various units, offers instant calculations with copyable results, and includes formulas for reference. Designed for privacy and efficiency, it works seamlessly on iOS devices.

**Highlights:** Instant pendulum calculations, Copyable results, Included formulas, Supports various units, High precision (16 decimal places), Ad-free and private

**Features:** macOS Compatibility

**In-app purchases:** none


### ZEFNET Charge

[App page](https://appshunter.io/ios/app/zefnet-charge/id1470100874)

Find and use public electric vehicle charging stations. Monitor and control your home charging unit, with options to override utility program restrictions for emergency charging.

**Highlights:** Find public chargers, Start/stop charging sessions, Secure in-app payments, Monitor home charger usage, Control home charger, Override charging restrictions

**Features:** macOS Compatibility

**In-app purchases:** none


## Frequently asked questions

### Is Simple Pendulum Calculator free?

Simple Pendulum Calculator costs $2.99, with no in-app purchases.

### Is ZEFNET Charge free?

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

### Which has better reviews, Simple Pendulum Calculator or ZEFNET Charge?

Simple Pendulum Calculator is rated higher. Simple Pendulum Calculator averages 5.0 out of 5 from 1 ratings, while ZEFNET Charge averages 2.0 from 6 ratings.

### Do Simple Pendulum Calculator or ZEFNET Charge have ads?

Neither Simple Pendulum Calculator nor ZEFNET Charge shows ads.

### Which is updated more often, Simple Pendulum Calculator or ZEFNET Charge?

Simple Pendulum Calculator ships an update every 31 months, and ZEFNET Charge every 4 months. Most recently, Simple Pendulum Calculator was updated on September 29, 2026 and ZEFNET Charge on October 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.*