When we talk about the electricity a cell phone draws the key element is the adapter used when charging. As these devices get bigger and better every year, the battery capacity and energy usage also increase. Recent releases have come with significant upgrades in charging speed, but what does that mean for the overall power consumption?
Below we will discuss and test cell phone wattage, explain how to work it out for yourself, and calculate the total electricity required.
How Many Watts is a Phone Charger?
The average smartphone uses between 5 to 20 watts when charging.
The exact number depends on the size and model of your smartphone, plus the charging adapter you use.
For example, most phones prior to 2018 would use around 5W when plugged in. In recent years, the power consumption has increased to 15W – 20W when using a fast-charging adapter.
If you have a relatively new cell phone, the amount of power it draws is down to the charger you are using. As these devices have larger capacity batteries, the adapter is required to run at a higher wattage (15W to 20W) to deliver decent charging speeds. You might even see super chargers running at 40W too!
You will notice the difference in performance if you use an old charging adapter with a new smartphone. The recharge speed is very slow and sometimes the device will use power more quickly than it is charging!
How to Find Out Your smartphone Wattage
There are 3 ways you can work out the wattage of a smartphone.
- Check Product Specification
The quickest way is to look at the smartphone adapter’s specification. The watts (W) is usually written on a sticker on the base. If not, you can check the user manual or the manufacturer’s website for technical details.
- Use a Wattmeter
A wattmeter is brilliant for getting a live wattage reading and tracking total energy usage of any appliance. You can simply plug it into your smartphone to get instant information.
I used one to test my Huawei P20 smartphone which gave a live reading of 15W.
- Wattage Formula or Calculator
If you know the amperage and voltage of your smartphone you can use this to find the maximum watts. Simply use the formula Amps x Volts = Watts. Or you can head over to the ‘Watt Calculator’ to work this out.
Smartphone Wattage Examples
Let’s take a look at specific examples of how many watts a smartphone draws. Below is a collection of modern smartphones with their listed power ratings.
| Smartphone Adapter Model | Power Rating (Watts) |
| HUAWEI SuperCharge | 40 |
| HUAWEI Wireless Quick Charge | 15 |
| iPhone 11 (and earlier) | 5 |
| iPhone 12 (onwards) | 20 |
| Samsung adaptive fast charging | 15 |
| Samsung super fast charging | 25 |
| Google Pixel 6 adapter | 21 |
| Sunmi travel adapter | 8 |
As you can see, the power ratings vary between different smartphones. So you should take the time to check your own appliance.
How Much Electricity Does a Phone Use?
You can use smartphone wattage to work out how much electricity it uses. Plus this can be useful in understanding how much it costs to run your smartphone.
A watt (W) is a measurement of power at a single point in time. A watt-hour is the total amount of electricity used in an hour. For example, a smartphone drawing 15W would use 15Wh when running for an hour.
Happily, electricity bills are recorded in kilowatt-hours (kWh). A kilowatt is simply 1000 watts. So a 15W smartphone charging for 1 hour uses 0.015kWh.
Let’s say you charge a phone for 1 hours a day with a 15W adapter. This means a smartphone uses 15Wh or 0.015kWh electricity a day. That’s 0.45kWh a month and 5.475kWh a year.
That’s an electricity cost of $0.82 a year to quickly charge your phone battery for 1 hour each day.
Not much electricity to keep your phone fully juiced up! 1 hour of quick charging should give you a full charge on a modern smartphone.
Charging a Smartphone Off-Grid
If you’re living off-grid, going camping, or on an adventure then you’ll probably be keen to keep your cell phone charged.
You might be relying on it for maps, directions, photos, and emergencies. There’s a number of options you can consider. It is important to take into account the power consumption of a modern phone to ensure you can cope with the demands.
If you try to use old or low powered wires and equipment then you might struggle to get a decent charge. Ensure you select a power bank, portable power station, power inverter, or solar panel with enough speed and capacity.
You can find a number of powerful yet portable car inverters, backpacking solar panels, and more to suit your needs. I suggest you ensure it can output at least 20W to give you decent charging speeds!
How Many Watts Does Charging a Phone Use Summary
I hope you now have a clear understanding of how many watts a smartphone uses.
The power consumption of these devices when charging is increasing all the time. The move to super-fast charging is producing a wattage draw of 20W and more! This is because phone batteries are becoming larger in energy storage capacity and the devices are guzzling more energy. So the high-speed charging adapters are necessary to keep up. That being said, if you want to reduce the electricity usage of your device then look for an efficient model using a 5W charger. Or you could even try an eco-friendly solar panel for extra charge.
