A battery’s capacity or mAh is a measurement of how many milliamp hours it can store. It’s easy to understand once you know that one amp-hour of electricity can power a light bulb for one hour.

So, if your camera battery can hold 1,600 photos per charge, it has a capacity of 1,600 photos per charge. Similarly, if a camera battery holds 2,000 mah, it has a capacity of 2,000 Milliamp hours (or mah).
Many digital cameras have the ability to determine their own power source (e.g., internal rechargeable battery or an external powered accessory such as an external flash).

In these cases the camera displays its true capacity in milliamp-hours instead of photos.

Thankfully though most cameras and camcorders are simple to operate with genuine batteries and external chargers which means you don’t need any special knowledge to figure out what yours actually holds without having to first disassemble or open up your device.

How to calculate battery capacity in mah

If you do have a digital camera or camcorder that has an internal rechargeable battery, you can use this simple calculator to find what your battery’s capacity is in milliamp-hours.
1/1000th of 1 amp hour = 0.001 wh
2/1000th of 1 amp hour = 0.002 wh
3/1000th of 1 amp hour = 0.003 wh
4/1000th of 1 amp hour = 0.004 wh
5/1000th of 1 amp hour = 0.005 wh
6/1000th of 1 amp hour = 0.006 wh
7/1000th of 1 amp hour = 0.007 wh
8/1000th of 1 amp hour = 0.008 wh
9/1000th of 1 amp hour = 0.009 wh
10/1000th of 1 amp hour = 0.01 wh

Theoretical calculation for battery capacity in mah

Battery capacity can be calculated by multiplying the battery voltage (V) by the battery capacity (mAh). For example, a Canon DSLR with a rechargeable battery that can hold 3,200 mah would have a theoretical capacity of 9,600 mAh.
Note that this is just an estimate because different types of batteries are measured differently and it varies depending on the manufacturer. Actual battery capacity may vary more than the theoretical calculation suggests. Just remember to consider all factors when calculating your real-life battery performance.

Get the mAh rating of your battery

To figure out your battery’s mAh rating, simply look for a label on the outside of your device that says the capacity in milliamp-hours. If you can’t find one, try opening up your camera and looking for a sticker on your battery that displays the capacity in milliamp-hours.
If you want to get an exact number from your camera or camcorder, usually keeping it fully charged is the easiest way to tell if it’s holding its charge.

Keeping your battery fully charged will allow you to monitor how many milliamp-hours are needed to be stored before it dies completely. This is determined by using a multimeter electronic test tool like this one:

Calculate Wh (Weight in grams)

To calculate how much weight your batteries weigh, you need to convert the mAh. So, if you have a camera battery with 2,000 mah, it weighs .4 grams.

Now that you know the weight for your batteries and their capacity, you can easily figure out how many WH hours your battery will last by multiplying your weight in grams by the number of mah in the battery.
If you want to power something for a specific amount of hours and don’t want to be without it for overcharging then it’s important not to discharge your batteries beyond 50 percent capacity.
This is why some camcorders may display “Max Battery Capacity” instead of “Battery Lifetime.” The purpose of Max Battery Capacity is to show how many Wh hours are available before reaching 50% capacity or Max Battery Capacity which is similar to “Battery Lifetime.”

Weight = mah x density (in g/cm^3)

Most digital cameras and camcorders use AA, AAA or LR6 batteries with a capacity of 1.5, 1.2 or 1ah respectively. The weight (in grams) of these batteries is determined by multiplying their capacity in milliamp-hours by the density of the battery’s material in g/cm^3:

Weight = mah x density (in g/cm^3)
Weight = 15mah x .0043 kg/m3 = .7kg

Conclusion

The weight in grams of a battery is calculated by multiplying its mah rating by the density in grams per cubic centimeter.

This formula can be used to calculate the weight of a battery in kilograms or pounds. The calculation can also be used to determine the weight in ounces of a battery that has a mAh rating.