# Ohm's Law vs Ref Tools

The clearest difference is rating: Ohm's Law at 4.7 against Ref Tools's 3.9. Ohm's Law also leads on review sentiment (81% vs 58%) and ratings volume (165 vs 52). Ref Tools's advantage is in-app purchases (none vs 1) and update cadence (every 5 weeks vs every 4 months). On price, ads and device support there is nothing between them.

Both are free to download. Ohm's Law sells 1 one-off in-app purchase. Ref Tools asks for nothing beyond the download.

Ohm's Law holds the better App Store score, 4.7 against 3.9. Both are backed by a comparable volume of ratings — 165 and 52 respectively. Written reviews point the same way: 81% of Ohm's Law's written reviews are positive against 58% of Ref Tools's.

Ohm's Law ships an update every 4 months, Ref Tools every 5 weeks. The most recent releases landed on October 13, 2026 and October 7, 2026 respectively.

## The numbers

| Metric | Ohm's Law | Ref Tools |
| --- | --- | --- |
| Price | Free | Free |
| Rating | **[4.7 (165 ratings)](https://appshunter.io/ios/app/ohms-law/id389305829/reviews)** | [3.9 (52 ratings)](https://appshunter.io/ios/app/ref-tools/id472312541/reviews) |
| Number of ratings | **165** | 52 |
| Positive reviews | **80.7% of reviews** | 57.6% of reviews |
| In-app purchases | Yes | **No** |
| Ads | No | No |
| Update frequency | Every 4 months | **Every 5 weeks** |
| Monetization | Free with in-app purchases | **Free** |
| Size | 9 MB | 98 MB |
| Requires iOS | **9.0** | 15.0 |
| Devices | iPhone, iPod | **iPhone, iPad, iPod** |
| Age rating | 4+ | 4+ |
| Developer | [Creature Code Mobile, LLC](https://appshunter.io/developer/386736750) | [Danfoss A/S](https://appshunter.io/developer/423984644) |

## What reviewers say

### Ohm's Law

[App page](https://appshunter.io/ios/app/ohms-law/id389305829)

This utility app calculates electrical resistance, voltage, and current using Ohm's Law. It provides a quick and easy way to solve electrical formulas for various applications.

**Highlights:** Ohm's Law calculations, Voltage calculation, Current calculation, Resistance calculation, Electrical formula solver

**Features:** macOS Compatibility

**In-app purchases (1)**

| Purchase | Price | Billing |
| --- | --- | --- |
| Remove Ads | $0.99 | one-time |

**What reviewers like**

- 👍 Extremely user-friendly and intuitive interface
- ⚡ Fast and accurate calculations
- 🎯 Simple, focused design with no unnecessary clutter
- 💰 Free app with minimal ads that don't interfere
- 🔧 Requires only two values to calculate the rest

**What reviewers complain about**

- 🐛 Crashes when entering decimal values in multiple fields
- 🐛 Reset function doesn't work properly after first use
- ⚠️ App incompatible with newer iOS versions
- ⚠️ Outdated and hasn't been updated since iOS 6
- ❌ Limited functionality - single resistor only

**Reported bugs**

- App crashes when entering decimal points in multiple fields simultaneously
- Reset button fails to clear values after first use
- Large calculations cause app to crash
- Crashes on iPhone SE and iPhone 7 Plus with iOS 10+
- App won't open or frequently crashes on some devices

**Requested features**

- AC/DC checkbox option
- Three-phase power calculations
- Parallel and combination circuit support
- Impedance and reactance calculations
- Ohm's Wheel reference tool


### Ref Tools

[App page](https://appshunter.io/ios/app/ref-tools/id472312541)

This app provides HVACR technicians with essential tools and information for field service. It includes refrigerant calculators, troubleshooting guides, product finders, and access to spare parts. Listen to educational podcasts to enhance your knowledge on the go.

**Highlights:** Refrigerant Slider for P/T calculations, Solenoid valve coil testing tool, Refrigeration system troubleshooting guide, Product data finder, Spare parts ordering, Low-GWP refrigerant comparison, TXV Superheat optimization, Educational podcasts

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

**In-app purchases:** none

**What reviewers like**

- 👍 Useful tool for HVAC/R techs
- 👍 Great idea for an app
- 👍 Best refrigeration and hvac app
- 👍 Useful App for HVACR
- 👍 Brilliant app

**What reviewers complain about**

- 🐛 Crashes instantly on launch
- 🐛 App won’t open on iPhone
- 🐛 Flashes up and disappears
- 🐛 Cannot open app
- 🐛 Immediately shuts off

**Reported bugs**

- CRASHED instantly on Mac Mini M4
- App won’t open on iPhone
- App flashes up and disappears
- Cannot open app
- Immediately shuts off since recent release

**Requested features**

- More residential AC information
- Troubleshooter for Residential & Commercial
- Add SP22 refrigerant
- Add R-11 refrigerant
- Add R-123 range down to 40 degrees


## Frequently asked questions

### Is Ohm's Law free?

Ohm's Law is free to download, with in-app purchases available.

### Is Ref Tools free?

Ref Tools is free to download, with no in-app purchases.

### Which has better reviews, Ohm's Law or Ref Tools?

Ohm's Law is rated higher. Ohm's Law averages 4.7 out of 5 from 165 ratings, while Ref Tools averages 3.9 from 52 ratings.

### Do Ohm's Law or Ref Tools have ads?

Neither Ohm's Law nor Ref Tools shows ads.

### Which is updated more often, Ohm's Law or Ref Tools?

Ohm's Law ships an update every 4 months, and Ref Tools every 5 weeks. Most recently, Ohm's Law was updated on October 13, 2026 and Ref Tools on October 7, 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.*