Ah to kWh Calculator To choose a battery for your RV or figure out how much power your solar panels can store, you need to know how many Amp-Hours (Ah) and kilowatt-hours (kWh)
Amp-hours (Ah) tell you how long a battery can power something. Kilowatt-hours (kWh) measure the total amount of energy used or stored.
Understanding how to convert between Ah and kWh is important when comparing different energy options.
Our simple Ah to kWh calculator makes this conversion quick and easy. Use it to switch between these units and understand your energy needs easily.
What are Amp-Hours (Ah) and Kilowatt-Hours (kWh)?
Amp-Hours (Ah) is a way to measure the capacity of a battery. It tells you how much electric charge a battery can store or deliver.
Think of it as the size of a fuel tank in your car—bigger tanks let you travel farther, and higher Ah batteries can power devices for longer.
- Batteries: Commonly found on car batteries, power banks, and solar systems.
- Electronics: Helps determine how long a device can run on a full charge.
Imagine a 10 Ah battery. Connecting a device that uses 1 amp of current will run for 10 hours before the battery is empty. If your device uses two amps, the same battery will last only 5 hours.
Kilowatt-hours (kWh) measure energy usage. It tells you how much electricity is consumed or stored over time. This is the unit you often see on your electricity bill.
- kWh calculates the total power consumption of appliances, devices, or entire households.
- It combines the amount of power (watts) and the time it’s used.
If you use a 100-watt light bulb for 10 hours, it will consume 1 kWh of energy. Similarly, a 1,000-watt (1 kilowatt) appliance running for 1 hour also uses 1 kWh.
Amp-Hours to Kilowatt-Hours FormulaAmp-Hours to Kilowatt-Hours Formula
Use the formula below to convert Amp-Hours (Ah) to Kilowatt-Hours (kWh):
For example, if your battery has 100 Ah and 12 V:
FAQ
What is the difference between Amp-Hours (Ah) and milliamp-hours (mAh)?
Amp-hours (Ah) and milliamp-hours (mAh) both measure electric charge, but they use different scales. One amp-hour (1 Ah) is equal to 1000 milliamp-hours (1000 mAh). So, a 10 Ah battery has the same capacity as a 10,000 mAh battery. mAh is often used for smaller batteries, like those in cell phones and laptops, while Ah is used for larger batteries, like car batteries or deep-cycle batteries.
Does a higher Ah rating mean a battery is more powerful?
Not exactly. A higher Ah rating means the battery can deliver a certain amount of current for a longer period. It indicates the battery’s capacity, not its power output. Power (measured in watts or kilowatts) is related to both current (amps) and voltage. A battery with a higher Ah rating *at the same voltage* will generally provide power for longer than a battery with a lower Ah rating.
How do I find the voltage of my battery?
The voltage is usually printed directly on the battery label. Look for a number followed by “V” (e.g., 12V, 6V, 3.7V). If it’s not readily visible, consult the battery’s documentation or the device it powers.
Can I convert Ah to watts or kilowatts directly?
No. You can’t directly convert Ah to watts (W) or kilowatts (kW). Ah measures charge, while watts and kilowatts measure power. To convert Ah to power (and subsequently to kWh), you need to know the voltage (V) of the battery. The formula for power is: Power (W) = Voltage (V) * Current (A).
Why is voltage important in the Ah to kWh conversion?
Voltage is crucial because it represents the “push” of the electrical current. A higher voltage means more energy is transferred per unit of charge. Therefore, the same Ah rating at a higher voltage will result in a higher kWh value (more total energy).
If I know the wattage of a device and the Ah of a battery, how can I estimate how long the battery will last?
First, you need the battery’s voltage. Then, calculate the current (Amps) the device draws using the formula: Current (A) = Power (W) / Voltage (V). Once you have the current, you can estimate the runtime by dividing the battery’s Ah rating by the device’s current draw: Runtime (hours) = Battery Ah / Device Current (A). This is an *estimate* as real-world conditions can affect battery performance.
Is there an easy way to remember the Ah to kWh formula?
Think of it this way: You’re converting “amp-hours” to “kilo-watt-hours.” You need to introduce voltage (V) to get to watts (V * A = W). Then, since you want kilo-watt-hours, you divide by 1000: kWh = (Ah * V) / 1000.
