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How Much Power Does a Phone or Tablet Use While Charging?
Jan 28, 2016MobileComments (4)
The amount of power your mobile device consumes while charging depends on the amperage rate of your charger. This should be listed on the plug-in part of the charger in very small print. For phones it is usually around 1.2A at 5.0V. For tablets it is usually around 2.0A at 5.0V. USB charging usually delivers 500mA (0.5A) at 5.0V.

Higher amps means a faster charge and more power consumption. Most devices use 5 volts, so you can calculate how much power in watts is being used with the simple equation Volts * Amps = Watts:


As you can see, the amount of power being used is roughly similar to an LED light bulb, or maybe a small fan.

How Much It Costs

Let's say you charge your device for 2 hours every other day at 1.2A. That means you'll spend 365 hours charging your device in a year. At 6 watts, that's 2190 watt-hours, or 2.19 kilowatt-hours (kWh). If your utility company charges 12 cents per kWh (rough US average), then that means it costs you 26 cents per year to keep your device charged up.


The actual power usage varies a bit. Using a Kill-A-Watt I found that my Nexus 5 with factory LG charger (1.2A at 5.0V) used between 6.5 to 7.7 watts depending on if the screen was on or off, and what I was doing with it while it was charging.
Comments (4)
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nhgyy   Aug 30, 2021
This page helped me with my school project so thank you.
Munsif   Mar 04, 2019
Thanks for some voltage information. Actually what is the difference between a charger and adapter. My small tablet,s power keeps dropping despite attaching a charger so I decided to keep getting power for my tablet thru an adapter, is it ok to use a.c to d.c power adapter with 2 amp and 5 volts. A chemical used in dry battery depends upon the frequency of charge given by a charger. If it charges fast a device the power will also drop fast. Consider the gap between charge points,
florida wilson   Sep 17, 2018
I just read through the entire article of yours and it was quite good. I really appreciate the topic which you discussed over here. it helps the user. I am using Dell laptop and battery is connected and charging. But as soon as I unplug the AC adapter, the laptop shuts off completely. then I went through and they helped me a lot to resolve this issues.
nix   Oct 25, 2017
My phone has battery of 2000mAh and charger is of 5v 0.7A . How much it costs to fully charge my mobile?