A phone charger uses about 5-20 watts while charging, around 15 W on average, and almost nothing once the phone is full. Fast chargers are rated 20-60 W, but that is a maximum, reached only briefly.
- Running watts
- 15 WTypical; 5–60 W across models
- Starting watts
- NoneNo motor surge
- Per day
- 0.03 kWh2 h of use
- Current
- 0.1 AAt 120 V while running
Figures checked against DOE, ENERGY STAR and manufacturer data on . Your model's label is the final word.
Watts by model and setting
Most phone charger models draw between 5 and 60 W while running; a typical one draws about 15 W. 15 W x 2 h/day of active charging; an idle charger left plugged in draws a fraction of a watt.
- Charger rating: older 5 W cubes vs 20-60 W USB-C PD fast chargers
- Battery level: draw tapers as the phone nears full
- Wireless charging is less efficient than a cable
- Phone model: Apple recommends 18-20 W or more for fast charging older iPhones and 40-60 W for the newest Pro models
Running a phone charger on a generator or power station
- Generator: at least 15 running watts. A generator rated 1,000 W or more covers it with room to spare.
- Power station: continuous output of at least 15 W. Pure sine wave output is the safe choice for motors and electronics.
| Power station capacity | Estimated runtime |
|---|---|
| 500 Wh | 28.3 h |
| 1,000 Wh | 56.7 h |
| 2,000 Wh | 113.3 h |
| 3,000 Wh | 170 h |
Based on 15 W average draw and 85% usable capacity.
- Charge phones directly from a power station's USB ports to skip inverter losses
- A 100 Wh power bank or station can recharge a typical phone around 5-7 times
- Keep phones charged ahead of storms; they're key for alerts during outages
Add it to the generator calculator
Questions people ask
Does a phone charger use electricity when nothing is plugged in?
A tiny amount, typically well under half a watt for modern chargers. It adds up to only a few cents a year.
How many watts do I need to fast charge an iPhone?
Apple calls for 18-20 W USB-C PD for most recent iPhones, 40 W or higher for iPhone 17 models, and about 60 W for iPhone 18 Pro models.