# Battery Calculator — Battery Life, Capacity & Size

> Utility for calculating battery life, capacity, and size using electrical formulas. (iPhone/iPad app by Nitrio.)

- Source: https://appshunter.io/ios/app/battery-calculator/id1229567971 (this page in markdown: same URL + `.md`)
- Developer: [Nitrio](https://appshunter.io/developer/321121189)
- Category: Utilities, Productivity
- Price: $2.99
- Rating: 1.50/5 from 4 App Store ratings · 6 written reviews indexed
- Age rating: 4+
- Requires: iOS 13.0 · 1 MB
- Languages: American English
- Released: 2017-04-26
- Data updated: 2026-07-25
- Monetization: paid
- User reviews in markdown: https://appshunter.io/ios/app/battery-calculator/id1229567971/reviews.md

## What is Battery Calculator?

Battery calculator include battery life calculator, battery capacity calculator and battery size calculator.
battery life calculator uses battery capacity and device consumption to calculate estimated run time of battery life.
battery size calculator calculates battery capacity, measured in amp hours based on energy stored in a battery, expressed in watt-hours and the voltage of the battery.
battery size calculator calculates required the battery rating in ampere hour based on load, duration and discharge level.

Formula:
Battery Life Calc
battery life = BC/DC * (BE/100)

where:
BC - capacity of your battery, measured in ampere hours [Ah] or miliampere hours [mAh]. This value is printed on your battery.
DC - average current draw from electronic device, expressed in amperes [A] or miliampere [mA]. 
BE - The battery efficiency is the ratio of the energy retrieved from the battery, to the energy provided to the battery, when coming back to the same SOC state. Lithium-ion stays close to 90%. Lead acid batteries are lower at about 90%, and nickel-based batteries are closer to 80%.


Battery Capacity Calc
E = V * Q

where:
E - energy stored in a battery, expressed in watt-hours [Wh] or kilowatt-hours [kWh].
V - voltage of the battery.
Q - battery capacity, measured in ampere hours [Ah] or miliampere hours [mAh].


Battery Size Calc
Current calculation:
If the load is specified in watt, the current  is calculated as:
I = P * V

where:
I - current in ampere.
P - power in watts.
V - voltage in volts.

Lithium-ion batteries size = (100*I*t) / (100–Q)

Lead-acid battery size = (100*I*t) / ((100−Q) * (0.02*t+0.6))

where: 
I - current in ampere.
t - duration in hours.
Q - required remaining charge in percentage.


A battery rated for 100 Amp hours will provide 5 Amps for 20 Hours.
If it is a 12 volt battery, multiply 100 by 12 and the battery will provide 1200 Watt Hours.
divide the result by 1000 and the battery can supply 1.2 kW hours for the metric 'kilo' prefix.
A kilowatt hour is a measure of energy used by an appliance if it were kept running for one hour. 
To keep in mind. Since the Amp Hour rating is a 20 Hour rating, so we need to treat kilowatt conversion as 20 hour rating.
For the 1200 Watt Hour conversion, the battery will provide 60 Watts for 20 Hours.

Ampere is an electrical unit used to measure the current flow towards the load. The battery life or capacity can be calculated from the input current rating of the battery and the load current of the circuit. Battery life will be high when the load current is less.

You can determine the time that how long the battery charge will last. For example, a circuit connected with 1000 mAh current rating and it is connected to the load of 20 mAh. Then the battery will last for 50 hours. Batteries are available in different current rating due to its high requirement of different industrial and domestic purposes. Any battery life can be easily calculated by the values of battery capacity in mAh/Ah and load current in mA/A.

Thanks for your support and do visit nitrio.com for more apps for your iOS devices.

## Key features

- Battery life calculator
- Battery capacity calculator
- Battery size calculator
- Estimate run time
- Calculate battery capacity in Wh
- Calculate required battery rating in Ah

## Chart rankings

- #179 in Top Paid · Utilities (US App Store)

## Recent user reviews (6 of 6)

All indexed reviews: https://appshunter.io/ios/app/battery-calculator/id1229567971/reviews.md

### 1/5 — Battery life calculator

*2020-05-11*

Do not purchase this tried to put in device consumption and it crashes and throws me completely out of the program and there is no section to get my money back !

### 1/5 — Crashes

*2019-06-21*

Just spent money on an app that crashes as soon as you type figures into it. Not impressed.

### 1/5 — Terrible - Should he pulled form App Store

*2019-01-27*

DO NOT BUY. Crashes, does not work.

### 1/5 — Terrible keeps crashing

*2018-07-18*

Keeps crashing when trying to input numbers. Terrible and worthless!

### 1/5 — Do not buy

*2018-05-28*

Fake program.    Does not work...

### 1/5 — Crashes on IOS11.3

*2018-04-03*

App crashes on IOS11.3 when changing mAh load setting . Please fix bug .

## Frequently asked questions about Battery Calculator

### What is Battery Calculator?

Battery Calculator is a utility app designed to help users calculate battery life, capacity, and size. It uses various electrical formulas to provide estimations based on user-inputted values.

### How does Battery Calculator estimate battery life?

It estimates battery life by using the battery's capacity (in Ah or mAh) and the device's average current draw (in A or mA), along with battery efficiency.

### Can Battery Calculator determine battery capacity?

Yes, it can calculate the energy stored in a battery (in Wh or kWh) by using the battery's voltage and its capacity (in Ah or mAh).

### What information is needed to calculate battery size?

To calculate the required battery rating in ampere-hours, you need to provide the load in watts, the duration in hours, and the desired remaining charge percentage.

### What devices is Battery Calculator compatible with?

Battery Calculator is available for iPhone, iPad, and iPod devices, supporting iOS.

### What is the price of Battery Calculator?

Battery Calculator is a paid application, priced at $2.99.

### How often is Battery Calculator updated?

The app was last updated on December 22, 2025, with version 1.3. This indicates a recent update, suggesting ongoing support.

### What is the age rating for Battery Calculator?

Battery Calculator has an age rating of 4+, making it suitable for a wide range of users.

## Version history (last 4 releases)

### 1.3 — 2025-12-22

- Updated for the newest devices.
- Minor bugs fixed.

### 1.2 — 2021-06-30

- Update for Newest Devices
- Bug Fixed
- Features Added
- UI Update

### 1.1 — 2018-03-21

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

- Update for Newest Devices
- Minor UI Update

### 1.0 — 2017-04-25

No release notes.

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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 2026-07-25.*