# NRG Optimizer vs SJ Resistor Calculator

The clearest difference is in-app purchases: NRG Optimizer at none against SJ Resistor Calculator's 5. NRG Optimizer also leads on ads (none vs shown) and iOS requirement (12.0 vs 16.0). SJ Resistor Calculator's advantage is update cadence (every 2 weeks vs every 13 months). On price and device support there is nothing between them.

Both are free to download. SJ Resistor Calculator sells 5 one-off in-app purchases. NRG Optimizer asks for nothing beyond the download.

NRG Optimizer ships an update every 13 months, SJ Resistor Calculator every 2 weeks. The most recent releases landed on September 29, 2026 and September 23, 2026 respectively.

## The numbers

| Metric | NRG Optimizer | SJ Resistor Calculator |
| --- | --- | --- |
| Price | Free | Free |
| Rating | — | **[5.0 (1 ratings)](https://appshunter.io/ios/app/sj-resistor-calculator/id6504838457/reviews)** |
| Number of ratings | — | **1** |
| In-app purchases | **No** | Yes |
| Ads | **No** | Yes |
| Update frequency | Every 13 months | **Every 2 weeks** |
| Monetization | — | Free with in-app purchases |
| Size | 154 MB | 4 MB |
| Requires iOS | **12.0** | 16.0 |
| Devices | iPhone, iPod | iPhone, iPad |
| Age rating | 4+ | 4+ |
| Developer | [T.G.L. Inc.](https://appshunter.io/developer/1629823848) | [Stephane JAILLIARD](https://appshunter.io/developer/1749751077) |

## What reviewers say

### NRG Optimizer

[App page](https://appshunter.io/ios/app/nrg-optimizer/id1629823846)

**Features:** macOS Compatibility

**In-app purchases:** none


### SJ Resistor Calculator

[App page](https://appshunter.io/ios/app/sj-resistor-calculator/id6504838457)

This tool simplifies resistor calculations for electronics enthusiasts, students, and professionals. It accurately decodes resistor color codes and performs series/parallel calculations for complex circuit analysis. Avoid manual errors and streamline your electronics projects.

**Highlights:** Resistor color code decoding (4, 5, 6 band), Series resistor calculations, Parallel resistor calculations, Accurate resistance and tolerance values, User-friendly interface

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

**In-app purchases (5)**

| Purchase | Price | Billing |
| --- | --- | --- |
| A coffee | $0.99 | one-time |
| A cookie | $2.99 | one-time |
| No ads | $4.99 | one-time |
| A lemon tart | $4.99 | one-time |
| A pizza | $9.99 | one-time |


## Frequently asked questions

### Is NRG Optimizer free?

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

### Is SJ Resistor Calculator free?

SJ Resistor Calculator is free to download, with in-app purchases available.

### Do NRG Optimizer or SJ Resistor Calculator have ads?

SJ Resistor Calculator shows ads; NRG Optimizer does not.

### Which is updated more often, NRG Optimizer or SJ Resistor Calculator?

NRG Optimizer ships an update every 13 months, and SJ Resistor Calculator every 2 weeks. Most recently, NRG Optimizer was updated on September 29, 2026 and SJ Resistor Calculator on September 23, 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.*