# Ohms Law Calc. vs NEMA Guide

The clearest difference is in-app purchases: NEMA Guide at none against Ohms Law Calc.'s 1. NEMA Guide also leads on ads (none vs shown) and update cadence (every 2 days vs every 2 months). Ohms Law Calc.'s advantage is ratings volume (1.3K vs 1). On price, device support and iOS requirement there is nothing between them.

Both are free to download. Ohms Law Calc. sells 1 one-off in-app purchase. NEMA Guide asks for nothing beyond the download.

NEMA Guide holds the better App Store score, 5.0 against 4.7. That said, the two scores are not equally well evidenced: Ohms Law Calc. has 1.3K ratings behind it against 1, so its average is the more settled of the two.

Ohms Law Calc. ships an update every 2 months, NEMA Guide every 2 days. The most recent releases landed on November 1, 2026 and October 30, 2026 respectively.

## The numbers

| Metric | Ohms Law Calc. | NEMA Guide |
| --- | --- | --- |
| Price | Free | Free |
| Rating | [4.7 (1.3K ratings)](https://appshunter.io/ios/app/ohms-law-calc/id491898006/reviews) | **[5.0 (1 ratings)](https://appshunter.io/ios/app/nema-guide/id6746103301/reviews)** |
| Number of ratings | **1.3K** | 1 |
| Positive reviews | 50.0% of reviews | — |
| In-app purchases | Yes | **No** |
| Ads | Yes | **No** |
| Update frequency | Every 2 months | **Every 2 days** |
| Monetization | Free with in-app purchases | **Free** |
| Size | 59 MB | 23 MB |
| Requires iOS | 17.6 | 17.6 |
| Devices | iPhone, iPad | iPhone, iPad |
| Age rating | 4+ | 4+ |
| Developer | [V PUGAZHENTHI](https://appshunter.io/developer/491898049) | [Red Zepp LLC](https://appshunter.io/developer/1812216821) |

## What reviewers say

### Ohms Law Calc.

[App page](https://appshunter.io/ios/app/ohms-law-calc/id491898006)

This app provides a comprehensive suite of electrical calculations, including Ohm's Law, voltage drop, wire sizing, and impedance. It also offers numerous converters for various electrical units and parameters, aiding in circuit design and analysis.

**Highlights:** Ohm's Law calculations, Voltage drop calculator, Wire size calculator, Impedance calculations (R, L, C), Electrical unit converters, Power and current conversions, Circuit design tools

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

**In-app purchases (1)**

| Purchase | Price | Billing |
| --- | --- | --- |
| Ohms Law Calc. | $3.99 | one-time |

**What reviewers like**

- 🚀 Great value
- 🚀 Works perfectly
- 🚀 Fantastic app
- 👍 Best thing since sliced bread
- 🚀 Useful for electrical work

**What reviewers complain about**

- 👎 Have to pay again for an app already purchased
- 👎 Not easy to use
- 🐛 Paid but not unlocked, no response from developer
- 👎 Annoying pop-ups
- 🐛 Keeps shutting down

**Reported bugs**

- Paid version not unlocking
- Repeatedly prompting for payment after already paid
- Keyboard overlaying results making it difficult to see

**Requested features**

- Add more electrical conversions and calculations
- Add ability to input voltage and resistance to get amps and watts
- Add kVA, rms, and other popular needed conversions


### NEMA Guide

[App page](https://appshunter.io/ios/app/nema-guide/id6746103301)

Quickly identify and cross-reference NEMA plug and receptacle configurations with detailed illustrations and specifications. This tool streamlines the process for electricians and electrical professionals by allowing searches by NEMA number or filtering by various electrical parameters.

**Highlights:** Identify NEMA plug and receptacle configurations, Search by NEMA number, Filter by voltage, amperage, phase, poles, wires, and grounding, View matching configurations instantly, Over 170 configuration illustrations, Detailed specifications for each configuration, Offline data storage

**Features:** macOS Compatibility

**In-app purchases:** none


## Frequently asked questions

### Is Ohms Law Calc. free?

Ohms Law Calc. is free to download, with in-app purchases available.

### Is NEMA Guide free?

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

### Which has better reviews, Ohms Law Calc. or NEMA Guide?

NEMA Guide is rated higher. Ohms Law Calc. averages 4.7 out of 5 from 1.3K ratings, while NEMA Guide averages 5.0 from 1 ratings.

### Do Ohms Law Calc. or NEMA Guide have ads?

Ohms Law Calc. shows ads; NEMA Guide does not.

### Which is updated more often, Ohms Law Calc. or NEMA Guide?

Ohms Law Calc. ships an update every 2 months, and NEMA Guide every 2 days. Most recently, Ohms Law Calc. was updated on November 1, 2026 and NEMA Guide on October 30, 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.*