# Electrical Formulator

> Electrical calculation and conversion tool for engineers and electricians. (iPhone/iPad app by Historycentral.com.)

- Source: https://appshunter.io/ios/app/electrical-formulator/id299749412 (this page in markdown: same URL + `.md`)
- Developer: [Historycentral.com](https://appshunter.io/developer/1744330560)
- Category: Productivity, Reference
- Price: Free with in-app purchases
- Rating: 5.00/5 from 1 App Store ratings · 31 written reviews indexed
- Age rating: 4+
- Requires: iOS 18.4 · 16 MB
- Languages: American English
- Released: 2008-12-14
- Data updated: 2026-08-23
- Monetization: freemium
- User reviews in markdown: https://appshunter.io/ios/app/electrical-formulator/id299749412/reviews.md

## What is Electrical Formulator?

Electrical Formulator: Your Complete Electrical Calculation Tool

Solve virtually any electrical design or engineering challenge with this powerful and intuitive electrical formulator. Packed with hundreds of conversion and calculation tools, it’s the most versatile utility in your toolkit. Save, print, or email your results. Easily access your most-used and recently used formulas. Every calculation is automatically saved for future reference.



Key Features:
	•	Instant access to over 100 professional-grade electrical formulas
	•	Save and organize your results for later reference
	•	Share results via email or print
	•	Highlights your most-used and recent formulas
	•	Designed for engineers, electricians, and energy professionals



Formula Categories:

 Batteries
	•	Starting motor amperage
	•	Number of cells required
	•	Estimated operating time

Cost Calculations
	•	Appliance and lighting energy usage
	•	Estimated usage hours for new bulbs
	•	Insulation payback period

BTU Conversions
	•	BTU to joules, horsepower-hr, watt-hr, calories, foot-pounds, and more

 Generator Calculations
	•	DC generator output
	•	Generator amperage and efficiency

 Impedance & Reactance
	•	Resistance & reactance combinations
	•	Inductive and capacitive reactance
	•	Total impedance and parallel circuits

 Kilowatts & Joules
	•	Convert kilowatts to BTU/hr, joules/sec, lumens, horsepower, megajoules/hr, and more

 Motors
	•	Single- and three-phase motor calculations
	•	Locked rotor current
	•	Motor kVA (including multiple input scenarios)
	•	Motor speed analysis

Ohm’s Law
	•	Calculate for power, voltage, resistance, or current

Transformers
	•	Primary and secondary amperage
	•	Full-load transformer sizing (208V, 240V, 480V for single and three-phase)
	•	Impedance and amperage capacity calculations

Voltage Drop
	•	Copper and aluminum wire voltage drop (1-phase and 3-phase)
	•	US/Imperial and metric units supported

Wiring & Conduits
	•	Wire size and resistance (copper and aluminum)
	•	Wire length calculations
	•	Conduit sizing



Whether you’re working in the field, the lab, or the classroom, this electrical formulator helps you work faster, smarter, and with confidence.

Users are able to calculate twelve formulas for FREE. Purchase a subscription to calculate additional formulas. All subscriptions come with a 1-WEEK FREE TRIAL and SUPPORT Family Sharing.

## Key features

- Over 100 electrical formulas
- Save and organize results
- Share results via email or print
- Access most-used and recent formulas
- Supports US/Imperial and metric units
- Formula categories for batteries, motors, transformers, and more

## Pricing and in-app purchases

Base price: Free.

**One-time purchases**

| Purchase | Price | Type |
| --- | --- | --- |
| Pro Features For Electrcial | $1.99 | one-time |


## Recent user reviews (10 of 31)

All indexed reviews: https://appshunter.io/ios/app/electrical-formulator/id299749412/reviews.md

### 4/5 — Surprise app

*2020-01-11*

Wow..Imazing

### 5/5 — Eformulator

*2016-07-08*

Giving credit where credit is due. Had problems with Pro version, contacted author, very professional. Had resolved in less than 12 hours. How's that for dedication to your creation. Very informative for any level electrical reference and calculation.

Thanks for being helpful after the sale.

### 1/5 — App won't updat

*2013-05-11*

App has been attempting to update for a week now. Each time it errors out saying try later.  First time this has happened. Had this app for 3 yrs.

### 1/5 — Won't Update or Work

*2012-11-26*

With the latest update, it will not update and I cannot open the app to use either. It just sits there waiting to update but keeps getting the message of unable to update at this time. Will change the rating once it begins to work again.

### 3/5 — Show the formula

*2012-09-07*

Good application. It would be great if you could show the formula that is being used along with the answer

### 1/5 — Don't get this!

*2012-04-05*

Worst app for your money, results are inaccurate. How do I get my money back?

### 1/5 — Help

*2012-03-14*

I have purchased thus app but I can't get the app to open. I have an iPhone, the app used to work but stopped working. Anyone any solutions???

### 1/5 — Poor, very poor

*2011-10-23*

I am at a loss as to why this app has a rating of 3.5 out of 5.

I found the app of little use - most of the results are highly inaccurate. As a professional engineer, many of the formulae are dangerously misleading.

Some of the formulae are missing - they simply describe the method, but do not produce a result.

### 5/5 — Outstanding!

*2011-10-19*

This app has been a huge help, and will continue to be an invaluable reference for me. I've used it extensively during my Electrical and Instrumentation apprenticeship.

### 1/5 — Colin Mark

*2011-06-19*

Worst app ever waste of money. It's useless there is no way it is 4 stars. I wouldn't even give it 1.

## Frequently asked questions about Electrical Formulator

### What does the Electrical Formulator app do?

The Electrical Formulator app is a comprehensive tool designed to help engineers, electricians, and energy professionals solve electrical design and engineering challenges. It provides access to hundreds of conversion and calculation tools, covering a wide range of categories like motors, transformers, Ohm's Law, and voltage drop.

### What are the key features of the Electrical Formulator app?

Key features include instant access to over 100 professional-grade electrical formulas, the ability to save and organize results, share them via email or print, and quick access to your most-used and recently used formulas. All calculations are automatically saved for future reference.

### How much does the Electrical Formulator app cost?

The app offers a freemium model. Users can calculate twelve formulas for free. To access additional formulas, a subscription is required. All subscriptions include a 1-week free trial and support Family Sharing.

### What types of electrical calculations can I perform with this app?

You can perform a wide array of calculations, including battery calculations (starting amperage, number of cells), cost calculations (energy usage, payback periods), BTU conversions, generator calculations, impedance and reactance, kilowatt and joule conversions, motor calculations, Ohm's Law, transformer calculations, voltage drop for various wire types, and wiring and conduit sizing.

### Is the Electrical Formulator app compatible with different units of measurement?

Yes, the app supports both US/Imperial and metric units for calculations such as voltage drop and wire sizing. This ensures versatility for users working in different regions or with different project specifications.

## Version history (last 5 releases)

### 6.0 — 2025-06-09

Completely rewritten from scratch.  New interface, ability to save multiple results, and ability to export results.

### 5.0.1 — 2016-07-07

This app has been updated by Apple to display the Apple Watch app icon.

Pro Bug Fix

### 5.0 — 2016-06-27

Totally redone code.  Basis for future growth.  Redone UI.  Ability to see underlying formulas if you unlock pro version

### 4.2.5 — 2013-05-10

new charts

### 4.2 — 2013-03-25

New Formula, small bug fixes

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All apps by Historycentral.com: https://appshunter.io/developer/1744330560

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*Data collected daily from the US App Store and indexed by [AppsHunter](https://appshunter.io/). User reviews are verbatim App Store reviews. Ratings, prices and chart positions refresh continuously; this snapshot is from 2026-08-23.*