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How many watts does a phone charger use: Little vampires
- Updated: Feb 05, 2025
- Created: Mar 04, 2024
- 7 min
Edited by: Andrei Gorichenskii
The average American spends about 3.5 hours a day on their smartphone. Have you ever wondered how much electricity your smartphone consumes? And how many watts does a phone charger use, especially when you leave it plugged in 24/7? We’ll break it all down for you.
Key takeaways
- The average phone might require somewhere about 19 watt-hours for a full charge.
- For every watt given to the device, the charger draws between 1.1 and 2 watts from the outlet.
- Left plugged in, your phone charger consumes up to 0.5 of a watt, making about 4.5kW per year.
- Energy vampires suck from $100 to $200 a year.
Your smartphone consumption and how to guesstimate it
To find the power your phone needs to charge from zero to full, we need to know the capacity and voltage of your phone’s battery. These can be either found on the battery itself or in your phone’s specification or figured out by installing a special app. On average, phones have a battery capacity of about 5000mAh and a voltage of about 3.8V. To estimate the consumption needed for a full charge, we multiply milliampere-hours by volts and divide by 1000.
Watt-hours = Milliampere-hours × Volts
Volts, amps, watts – what’s the difference?
Your electric usage is measured in several important ways, each helping to explain how power moves through your home and how your appliances consume energy. These measurements work together to determine both your home's power capacity and your monthly bill.
The basic flow of electricity depends on volts and amps working together. While volts create the pressure that pushes electricity through your wiring, amps tell you how much electricity is actually flowing. Multiply these together and you get watts, which show how much power your appliances need to run. Each appliance has different power needs - your refrigerator might consume hundreds of watts, while a small LED light unit might use just a few.
The key measure that appears on your electric bill is the kilowatt-hour, which tracks your total power consumption over time. When an appliance using 1,000 watts (one kilowatt) runs for an hour, it consumes one kilowatt-hour of energy. Your power company adds up all these usage units from your various appliances to calculate your monthly charges. This system makes it easy to understand why high-capacity appliances like air conditioners or electric heaters can have such a big impact on your bill.
The basic flow of electricity depends on volts and amps working together. While volts create the pressure that pushes electricity through your wiring, amps tell you how much electricity is actually flowing. Multiply these together and you get watts, which show how much power your appliances need to run. Each appliance has different power needs - your refrigerator might consume hundreds of watts, while a small LED light unit might use just a few.
The key measure that appears on your electric bill is the kilowatt-hour, which tracks your total power consumption over time. When an appliance using 1,000 watts (one kilowatt) runs for an hour, it consumes one kilowatt-hour of energy. Your power company adds up all these usage units from your various appliances to calculate your monthly charges. This system makes it easy to understand why high-capacity appliances like air conditioners or electric heaters can have such a big impact on your bill.
The average phone might require somewhere about 19 watt-hours for a full charge. But that isn’t the power the charger actually draws. The difference between the power taken from the outlet and the power flowing to your phone is in the charger’s efficiency. The efficiency of chargers can range from 50% to over 90%. In other words, for every watt given to the device, the charger draws between 1.1 and 2 watts from the outlet.
Charger’s efficiency ranges from 50% to over 90%
Monthly and yearly costs to charge a phone by state
The consumption cost heavily depends on the cost of electricity, and each state has its own cost per kilowatt hour. Let's see how much it would cost you to charge your phone every day throughout the year.
Do fast phone chargers draw more power than standard ones?
Fast chargers operate at a higher wattage and can deliver more electrical power to the phone’s battery to achieve faster charging speeds. While they consume more power, the overall increase in electricity usage is usually minimal. The time saved on charging often outweighs the slightly higher energy consumption.
Let’s say you fully charge your phone every day and your charger’s efficiency is about 80%. That makes 23Wh per day, 690Wh per month, and 8.5kWh per year, assuming you always plug the charger out when your phone is charged. Do you, by the way?
Energy vampires and how to find them
The energy vampires are electronic devices that continue to consume electricity even when they’re seemingly turned off but still connected to the mains. They lurk in standby mode, while their tiny lights and internal processes silently suck power from the grid.
A plugged-in charger drains up to 0.5 watts even when not charging your phone
Your phone charger is one of them. Left plugged in, it consumes up to 0.5 of a watt. Per year, that makes about 4.5kW. Depending on the price per kWh in your state, it may cost you somewhere between ¢45 and $1.5 per year. It doesn’t sound like much but add a laptop, TV, coffee maker, game console, bedside lamp, and you’re running $100 to $200 a year for devices you don’t even use.
Check yourself: How to perform DIY home energy auditHow do we deal with energy vampires? Here are the tips from experienced vampire hunters:
Unplug unused electronics: This is the simplest and most effective way to eliminate vampire loads. When you’re not actively using electronics, simply pull the plug.
Use power strips: Plug electronics into power strips with on/off switches. This allows you to easily cut power to the entire group of devices with a single switch.
Look for energy-efficient models: When replacing appliances, opt for energy-efficient models that use less power even in standby mode.
Solar power and how to charge your phone on the go
What happens when you’re on the go and your phone’s battery starts to dwindle? A power bank can only take you so far. The solution for all the energy needs of a camper is solar power.
Portable solar panels can come in a wide variety of sizes and capacities. A 30-watt folding panel can easily fit in your pocket. You can hang it on your backpack to charge your phone on the go. Even such a small panel can charge your phone from dead to full in about two hours. With the more serious 200 and even 300-watt folding panels, you can charge not only your phone but also your laptop, GPS or even a mini-fridge.
A natural addition to solar panels is a power station. Together, they form a PV generator. Power station combines in itself an inverter, a charge controller and a small power bank — perfect for keeping you powered anywhere you go. Learn more in our article “Finding solar panels for a PV generator: Tips and tools”.
Looking for a bigger solar system?
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Julia Zaraeva
Author
Years of experience in translation and a love of nature help Julia find the right words to encourage going solar. She joined the team in 2023 and is happy to make her contribution to a greener future.
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