Ah to kWh | Amps-hour to kilowatt hour Calculator

Ah to kWh Calculator

Ah to kWh or Amps hour to kilowatt hour is the calculator often used to calculate the energy of the battery for a given time for this it would require to have three parameters current in battery capacity in Ampere hour, voltage in volts and the third one is calculated and is referred to as kilowatt hour.

Ah *



For converting kilowatt hour to Capacity Ah use this calculator

the formula behind the calculator is goes like this kWh = Ah*Volts/1000

and dimension wise it is clear that Amps*volts make Watts and multiplied with hours make it to kwh.

Sometimes battery specification is given in mAh which mean milli-amp-hour and need to convert it into again kwh so what you have to do simply divide mAh value by 100 to convert it into Ah and than you can proceed as follows. for example. 2500mAh lithium ion cell can also written as 2500/1000 = 2.5Ah, similarly 1000mAh = 1Ah.

let us take an example of a battery with 120Ah and a Voltage of 60V than the kWh will be calculated as 120Ah multiplied by voltage and than dividing it by 1000 we get 120*60/1000 = 7.2kWh

let us take one more example of 165Ah with a battery voltage of again 60V than 165*60/1000 = 9.9kWh

Why Ah to kWh is needed

people working in the field of electric vehicle often have used this calculations when they deal with battery systems. when the engineers deal with EV battery sometime they have the knowledge of Voltage and Capacity but they don’t know the energy present in the battery which is nothing but kWh.

sometime they know kwh and Ah but not voltage so in this calculator three parameters are used to calculate either one of the third parameter if two are known. kilowatt hour calculator is often needed to the electric vehicle engineers or battery management system engineers. so this is a very handy tools that can provide a quick results.

Application for kilowatt hour calculator

ampere hour to kilo watt hour calculation is used in the area of battery system especially BMS where constant monitoring of the battery parameters such as Ah and is needed and along with this other parameter such as voltage, current, charge.

this is important to monitor the normal operating condition’s and battery longer life people working in the field of electric vehicle knows this very well.

Relation between kilowatt hour and Amps-hour in a calculation

Amp-hour is the measure of an electric charge and Kilowatt hour is a unit used to measure electrical energy. To convert from electrical charge to energy, use this relation along with the voltage. kWh = Ah × V*1,000

“Battery capacity” is a measure (typically in Amp-hr) of the charge stored by the battery, and is determined by the mass of active material contained in the battery.

The battery capacity represents the maximum amount of energy that can be extracted from the battery under certain specified conditions.

to look into other calculators

Amps-hour or kilowatt hour which is best measure for battery capacity measurement ?

Technically Amps-hour is the best measure to calculate the capacity of the battery as compared to kilowatt hour, however it always keeps on changing, what is mentioned in the battery is the rated capacity from the manufacturer.

So to find the instantaneous value of rated capacity Ah suitable sensors to be used. Which measures continuous change in SOC of the battery.

On the other hand kilowatt hour or energy of the battery is the measure of instantaneous voltage and current over time, since it involves three parameters so it is hard to find the accurate capacity, secondly in capacity voltage is not accountable, only current and time is to be known.

What is an ampere and ampere-hour?

The short version is that the term ampere or amp measures electric current over time. You don’t often hear it mentioned in regard to electric cars, but it’s worth knowing what it is.

The long version is that it’s a unit for measuring the rate of electron flow (think electricity) or the flow of current in a conductor (something that conducts or controls electricity) in the space of a second.

The measure of this current is known as ampere. One ampere (A) has a standard definition of 6.24 x 10 to the power of 18 electrons flowing in a second. The more amps you have, the higher the current. It’s not necessary to understand this, but just know that a typical laptop computer draws a current of about 3A (three amps).

An amp hour (Ah) is a different unit to amps; it’s used to estimate the amount of energy a battery can hold. In simple terms, it’s used to define the amount of current a battery can supply in an hour.

Amp hours are therefore used to determine battery life. Amp hours divided by amps tell us the battery life in hours. So a 2Ah battery can draw two amps for an hour before it runs out, or four amps for half an hour.

What are kilowatts and kilowatt-hours?

Watts, on the other hand, are a unit of power. A watt is a measure of amps and voltage combined. Voltage can be thought of as the amount of electrical pressure a conductor or circuit has; the force that pushes the electrons along the circuit. Amps are the speed at which electrons move past a given point. Power, then, is a relation of both force and speed. The formula runs as follows: Power (Watts) = Amps x Volts.

Watts are used to define the amount of power that runs through a given power supply. A kilowatt (kW) is simply a thousand watts. A kilowatt-hour (kWh) – much like an amp hour – is different from a watt. A kilowatt-hour is a measure of energy – how much energy is consumed in a given period.

Electric-car batteries are usually measured in kilowatt-hours: you can think of this as being equivalent to the fuel-tank size of a petrol or diesel car. The bigger the battery, the more energy you have and the longer your electric car’s range will be.

This is useful for working out charging times, as chargers are always rated in terms of their power, measured in kW. So if you have a 7kW wallbox charger at home, it’ll take one hour to deliver 7kWh of electrical energy. Therefore, as a rule of thumb, you can divide a car’s battery capacity by the power of a charger to work out the charging time.

So a Nissan Leaf with a 40kWh battery that’s plugged into a 7kW charger will take around five-and-three-quarter hours to charge (40kWh ÷ 7kW = 5.71 hours). Electrical power can also be converted to mechanical power.

However, it’s important to note that this isn’t always true, especially in the case of fast or rapid chargers, which typically use a DC supply. In these cases, charging the final 20% of a nearly full battery will take longer than the first 20% of an empty one, as it becomes increasingly difficult to cram the energy into the cells at such a high rate.

This is why you’ll see many manufacturers quoting ’10-80%’ rapid-charge times. And because that final 20% is harder to fill using a rapid charger, many drivers choose to leave public charging stations once they’ve reached 80% rather than wait longer for the battery to fill up completely.

Ah to kWh conversion table

this conversion table is used as an example for quick calculations with similar specifications of Ah and Voltage, formula of conversion remains the same as discussed in the above sections.


1. What is a more reliable measure of a battery’s capacity, is it AH or KWH ?

Battery capacity is measured in terms of Ah whereas kWh is the measure of energy consumed by the electrical loads and involves the voltage information. Ah tells the amount of maximum charge that battery can provide in 1 hour of duration. kWh tells power consumed in 1 hour.

2. Why are electric car batteries measured in kWh and not Ah (amp hours) ?

because when it comes to EV main information we should have Range of the car. In case of EV we have kWh/km as the mileage analogy. to have an overview of how much EV can run for say 10 mins of charging batteries are often termed as kWh.

3. Why is a battery rating in AH ?

Battery is a source of charge and that’s why it is often required to know that how much charge it can deliver in 1 hour.

4. What is the unit measure of mobile battery capacity ?

Mobile batteries are small and therefore rated as mAh .