How Many Amps Does a Phone Charger Use? (Explained)

Phone chargers have for years remained unsung heroes. They are often one of the most used items in our homes, and yet we often exclude them from the list of appliances we have at home.

In fact, ask a friend now to name their everyday household items and see if they remember to list the phone charger. Chances are, they will not.

Even so, we all know that a phone charger is an essential item that we use daily. And today, I decided to do our humble chargers some justice by discussing them in more detail. So, how many amps does a phone charger use?

Well, whether you’ve come here intentionally or were just curious, I’m glad you stopped by. Keep reading to find out everything there is to know about phone chargers and their amperage usage.

Read: How Many Amps Does a TV Use?

How Many Amps Does a Phone Charger Use?

A phone charger draws about 0.08 amps to 2 amps at 120 volts. That’s almost twice as much as the charger sends to the phone, with the difference between the input and output going into heating.

When you look closely at your charger, you will notice that the manufacturer typically provides two sets of information — one for the input and the other for output. I took a simple pic of this Huawei adapter for illustration purposes;

As you can see, there’s information on the output, and below it, details of the charger’s output. In some chargers, the details are included on either side of it and, in some rare instances, at the top.

The output part tells us the maximum amount of power the charger can allow a mobile device to pull or draw from it, while the input is the maximum amount of power the charger can draw from the power outlet.

Surprisingly, most people think the output power is the power the charger uses. Yet, that’s not accurate. Instead, output rating provides information on what the charger can let a device fetch from it, an amount that differs from one device to another depending on how the connected device is designed.

The input details, on the other hand, aren’t necessarily about how much juice the charger pulls from the source. Instead, the input details indicate the maximum or worst-case scenario.

In essence, these details don’t disclose the charger’s typical draw from the power source. Visualize the input rating as the highest power threshold the charger must not exceed while drawing power from the outlet to prevent potential damage.

To offer clarity, let’s consider our example of a power adapter. The input information suggests that the charger draws 20 watts of power (100 volts x 0.2 A). But that’s at its maximum, which seldom happens.

For that reason, input information can’t give us reliable information on how much power a charger draws from the source. Input details spell the limit, but they don’t give the typical amp draw.

As such, we can’t rely on the input details to get the amperage draw of a charger. Instead, we have to work with the power output specs of the charger.

Actually, the only difference between the power drawn from the outlet and the one going to the connected device is one — efficiency!

A charger that’s 100% efficient would have an equal amount of input as output.

But unfortunately, such chargers don’t exist. In fact, for most chargers, 50% efficiency is the sweet spot. That’s to say, for every watt the charger draws from the outlet, it provides 0.5 watts of power to our devices.

Using our example, let’s see how much power the adapter draws;

Let’s begin by getting the output wattage;

Watts = Voltage x Amperage

= 5 x 1

= 5 watts

5 watts indicate the maximum wattage a phone can draw from this charger. And apparently, the charger has to draw more to supply 5 watts out of it. So, taking the efficiency of 50%, the charger must get 10 watts of power from the power source.

From there, we can easily get the amperage by dividing the watts by the American’s standard voltage (120V)

Amperes = Watts/Voltage

= 10/120

= 0.083 A

From our calculation, the phone charger uses about 0.083 amps when charging a phone at standard speed. And yes, with most chargers coming with similar specs, we can safely say that this figure is what a standard charger uses.

But then again, with technological advancement, chargers are now drawing more power to save on charging time. For instance, Xiaomi 11T Pro and vivo iQOO Neo7 Android phones come with a 120-watt charger (output), which means they draw about 240 watts from the power source. That’s 2 amps (240 watts/120 volts). The higher amps translate to a higher charging speed.

How Much Electricity Does a Phone Charger Use?

A phone charger uses about 30 to 80 watts of power depending on its wattage and the time it takes to charge the device. This range is quite low considering that we have appliances at home that use as much as over 1000 watts per use.

From our example above, we just saw that the charger draws 10 watts of power. And just so you know, wattage is always per hour. That’s 10 watts per hour. So, assuming it takes 3 hours to charge a device, that’s 30 watts of power (10 watts x 3).

Using the charger to charge a smartphone for 3 hours daily would consume 900 watts of power in a month and 10,800 watts in a year. Now, with the average U.S. household using about 886 kWh per month, 900 watts is less than 0.1% of the overall monthly power consumption of the household.

But then, this is just for a standard 5-watt charger. If we use a faster charger, say 120 watts, the power consumption will be higher. But then again, remember that higher wattage means the phone takes less time to charge.

For instance, the Xiaomi 11T Pro and vivo iQOO Neo7 take 17 minutes to deliver a full charge. So, a 120-watt charger will have used about 17/60 of its input in an hour. So, at 50% efficiency, a 120-watt version will consume about 68 watts of power (240 watts x 17/60).

At the same consumption rate, a 120-watt charger will use 2.04 kWh per month and 24.48 kWh per year. But of course, the actual usage is much lower than this since you won’t necessarily have to charge your smartphone every day from 0-100.

How Much Does It Cost To Power a Phone Charger?

It costs approximately $0.13 to $0.28 to power a phone charger for a month at the standard energy cost of $0.14 per Kilowatt (kW). So, in a year, it will cost about $1.56 to $3.36 to power a standard phone charger.

But as we’ve already said, the energy cost is likely on the lower side since you won’t have to charge your smartphone from 0-100% daily. Sometimes you’ll skip a day or two without charging. So, don’t be surprised when the actual amount of energy falls below $1.

But generally, if there’s a household item with little impact on your power bill, it’s most likely a phone charger. This is because it’s one of the accessories that uses negligible energy. In fact, its energy demand is lower than that of most LED light bulbs in our homes.

Importance of Amp Rating in Your Charger

The amp rating in your charger is important because it determines your device’s maximum charging speed. The higher the amps, the faster the power delivery, especially if your accessory is configured to support quick charge.

Amperage plays a pivotal role in determining the amount of time it’ll take to charge your device. For example, a 1-amp charger will take twice as long (technically) to charge your device as a 2-amp charger.

So, when shopping for a charger, go for one with higher amps. Holding all other factors constant, the higher rating will get the job done in a fraction of the time it would take a charger with a lower amperage.

But then again, remember that your phone won’t draw more amps than it’s designed to. So, if your mobile phone is designed to draw 2 amps, a 5-amp charger won’t make it charge faster (unless the device has a built-in charger controller).

Read: How Many Amps Does a Refrigerator Use

Is It OK To Use a Higher Amp Charger?

Using a higher amperage is OK and won’t affect the lifespan of your cell phone or damage the phone battery or other internal components. Usually, an accessory will draw as much power as it’s designed to handle, so the higher amperage won’t cause any difference.

As such, the next time you don’t have your charger with you and the available one seems to deliver more amperage than the one you’re used to, feel free to use it. It won’t make your phone overheat or anything like that.

Is Higher or Lower Amps Better?

Higher amps are good for a charger than lower amps. Higher amps will save you time and won’t make your phone overheat, unlike lower amps, which can trigger all sorts of problems. But again, stick to the charger that the manufacturer recommends.

When a charger’s output is lower than what your device is designed to take, your device will try to overwork the charger to try and meet its power needs. This will cause overheating for the charger, which will shorten its lifespan and, sometimes, that of the device.

So, be careful when using lower amp chargers with higher-power devices. The low rating doesn’t mean it will have a “more gentle” effect on your phone. You’d rather work with a higher amps charger if you didn’t get your hands on the recommended one.

What is the Proper Way to Charge Your Phone?

The proper way to charge your phone is to connect it to power when the battery level is at least 25% and plug it out before it hits 100%. That will preserve the lifespan of your battery. Usually, working with the 30 – 90% range is the best way to prolong your battery’s lifespan.

Lithium batteries use electrons to power our devices. When using the battery, the electrons flow through the negative (-) electrode, through the phone’s internal components, and then back to the battery through the positive (+) electrode.

Now, the more the battery’s capacity diminishes, leading to its eventual depletion. This is why lithium-ion batteries come with charge cycles. To preserve your battery’s lifespan, it’s highly recommended to partially charge your phone, as this will prevent the electrons from overworking.

Partial charging also helps keep your battery cool, which is another factor contributing to a battery’s longevity. And that means you should never leave your phone charging overnight!

Can I Charge My iPhone 7 With a 2.4 Amp Charger?

The iPhone 7 comes with a 1-amp 5V charger, which means it can work with higher amp chargers without problems. Plus, unlike most devices, iPhone 7 devices have an internal charger controller to draw more electrical current when needed. As such, there’s no need to worry about damaging your device when using a higher amp charger.

Actually, you can expect your iPhone 7 to adopt a charge rate of 2.0A, which is twice the rate of the original charger that comes with the device. So, a 2.4-amp charger will reduce your charging time by almost half.

Frequently Asked Questions (FAQS)

Read: How Many Amps Does a Water Heater Use?

Final Verdict

Your phone’s charger is an essential item that doesn’t use much electricity. Expect it to cost you a few cents monthly on energy bills and a buck or so every year. Even so, get to know the ideal charger for your device. Always use the recommended charger to avoid any problems. And if you have to decide between two chargers, go for the higher amp charger.