How to Check Your Powerbank Capacity

One of the most important features of a powerbank is its capacity. By keeping this number in mind, you can ensure that your powerbank lasts long enough for you to charge your phone again.

 Unfortunately, most manufacturers don’t disclose the exact capacity of their products. Instead, they use a different system to indicate how much charge the powerbank can store – not how much juice it can give you. 

Fortunately, there are ways to check it yourself even without any official information from the manufacturer. This article contains all you need to know about checking your powerbank’s capacity and picking one with sufficient juice to meet your needs.

Photo by SCREEN POST on Unsplash

What does checking powerbank capacity mean?

Capacity, in this context, refers to the amount of energy (or power) the powerbank can store. This is usually measured in watt-hours (Wh). The main difference between capacity and watt-hours is that watt-hours take into account the amount of charge lost over time. 

This is why you might see a powerbank advertised as having a capacity of 10,000mAh and another with a capacity of 12,000mAh despite them having the same amount of charge. The capacity of a powerbank is important because it determines how many times you can charge your devices with it before it runs out of charge itself. 

For example, if you have a powerbank with a capacity of 10,000mAh and a phone that uses 3000mAh per charge, you can charge your phone three times before the powerbank runs out.

Writing notes on how to check powerbank capacity
Photo by Cathryn Lavery on Unsplash

How to check the capacity of your powerbank

To continue the discussion, there are a few different methods you can use to check the capacity of your powerbank. Here’s a list of each method and how you can use it:

  • Check by weight: If you have an electronic scale, you can use it to weigh your powerbank. If your powerbank is 10,000mAh, it should weigh around one pound.
  • Check by voltage: If you have a multimeter, you can use it to take the voltage of your powerbank. If the voltage is around 11 volts, then your powerbank is approximately 10,000mAh.
  • Check by amps and milliampere-hour (mah): If you have a multimeter that can measure amps and mah, you can use it to test your powerbank. If the multimeter reads 2 amps at 10.5 volts, then your powerbank is approximately 10,000mAh.

To dive in a little deeper, here’s one of the cheapest ways to check your powerbank. For the purpose of demonstration we’ll be using a powerbank with 2600mAh.

First, you charge the powerbank (fully discharged) and get its Amp reading from the start to the finish. Then, you note the duration of the full charge. After that, you can figure out the mAh based on the duration and Amp readings.

Here are the steps.

  • Fully charge your powerbank.
  • Measure the voltage and current from a USB power source using a USB voltage current metre.
  • Immediately start a timer and begin charging an empty powerbank. Record the Amps reading immediately.
  • Notice the current before the powerbank is fully charged, as there will be no current once it is charged. You can check the last Amp reading using a camera if you used one.
  • Once you get Amp reading and charge duration time, you can now begin calculating. Here’s how:

Start at 0s powerbank empty –––– 0.7A = 700mA

Last at 3hours 53min 5sec powerbank full –––– 0.34A = 340mA

So, average at 0.52A = 520mA 

After that, multiply 520mA with the duration in hours, which is 2,019mAh (520mA X 3.88h)

There you go, this particular 2600mAh powerbank actually has 2,019mAh capacity.

This calculation is approximately 10% to 20% accurate. However, it should be enough to get an estimate of your powerbank’s capacity. 

Photo by MoovyGo

Moovy Mini Powerbank

The Moovy Mini Powerbank has 10000mAh capacity. It comes with dual USB output with 3.1A total output. The best part is that it’s designed  to weigh only 200gr. 

This device can hold power and it can charge your phone up to 3 times (depending on your phone’s battery capacity). It can even charge most tablets once. The dual USB output allows you to charge your smartphone and tablet simultaneously. Say farewell to slow charging!


When it comes to picking a powerbank, the most important thing is to make sure that it has enough juice to meet your needs. Fortunately, there are ways to check the capacity of your powerbank even without the manufacturer’s information. The capacity of a powerbank is important because it determines how many times you can charge your phone with it before it needs to be recharged. 

Hopefully, you’ll now be able to estimate your powerbanks capacity. Check out our blog for other tips and tricks!

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