How Many Amps Does a Cordless Drill Draw

How Many Amps Does a Cordless Drill Draw?

If you are learning how to use power tools such as cordless drills, the amount of power they draw is vital to know. All this electricity talk concerning power tools can be pretty confusing. You’ve got volts, amps, ampere-hours, and more to be concerned with.

However, you can estimate how long the battery will last if you know how many volts your drill is and how many amps it uses. Of course, you also need to know how powerful the battery is to calculate this.

Moreover, if you know how many amps your drill draws, you can calculate roughly how long the battery will last. This will enable you to better budget your time to use your drill efficiently before the battery runs out. So, how many amps does a cordless drill draw? First, let’s figure out what amps are and how this relates to your cordless drill’s battery.

Amps, Volts, and Ampere Hours

Before discussing anything else, you need to know what amps, volts, and ampere-hours are.

What Are Amps?

Electricity can be pretty confusing, and if you don’t know what amps are, knowing how many amps your drill draws is futile. In simplest terms, amps or amperes measure electrical current.

Technically speaking, an ampere is a measurement of how fast a current travels through a circuit. You could also say that amps or amperage is the strength of the current moving through a circuit.

You can compare this to water running through a hose, in which case, amps would be the water. It measures how fast water can move through the hose or, in this case, how fast the current moves through a circuit.

What Are Volts?

Volts can be confusing. This is another measure of electricity—volts measure the force of the electricity.

If we stick with our water and hose example, the voltage would be like measuring the water pressure inside the hose. On the other hand, amps or amperage would measure the water’s flow rate or the speed at which the water is flowing.

What Are Ampere Hours?

To determine how many amps your drill draws, you also need to know your battery’s energy storage capability. Storage capabilities of a battery are measured in Ah or ampere-hours. Therefore, when your drill is fully charged, it will last as long as the ampere-hour rating on the battery indicates.

Therefore, if you have a four-ampere hour battery, it will draw 4 amps for every hour it runs. However, this refers to the battery itself. You also need to know how much energy the drill draws. Therefore, paying attention to the ampere-hour rating for a cordless drill battery is always essential when purchasing a new drill.

How Many Amps Does a Cordless Drill Draw

How Many Amps Does a Cordless Drill Draw?

Now comes the part where we put the above components together to calculate how many amps a cordless drill draws.

Once again, we’ll use the same water/hose analogy. So, first, the more volts there are (or the more pressure the water is under), the more amps there will be, or the faster it will go.

A 20-volt cordless drill will draw more amps than an 18-volt cordless drill. On that note, you will need a battery that’s properly rated for the voltage of your drill.

Of course, how many amps a drill draws will differ based on how many watts the drill’s motor uses. It also depends on how many volts the drill’s battery has. Therefore, we will need to perform a simple calculation to determine how many amps your drill will drop.

Calculating How Many Amps a Cordless Drill Draws

The first thing is to check the drill’s motor to see how many watts it is rated for. Once you have this figure, determine how many volts the battery has.

These values should be listed on your product package. Also, check how many amps the drill itself draws.

This will allow you to calculate roughly how long the battery will last. First, divide the cordless drill’s motor watt rating by how many volts the battery has. This will tell you how many amps your drill draws.

As a rough example, if you have an 18-volt cordless drill with a 250-watt motor, it should draw 14 amps. However, if you have a battery rated for three-ampere hours, it will draw 1 amp every three hours.

Therefore, if your drill runs at 6 amps, you can expect the battery to last 30 minutes. However, with that same 3-ampere hour battery, if your drill draws only one amp, the battery should last for three hours, etc.


You should now know how to calculate how many amps your drill draws and then be able to calculate how long the battery will last on a full charge.

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