Phone / Tablet Charger Wattage for Generator Sizing
About the Phone / Tablet Charger
A smartphone or tablet charger drawing approximately 20 to 25 watts. Modern fast chargers may draw up to 45 watts during peak charging, but average draw over a full charge cycle is lower. There is no starting surge. Phone charging is typically the single most important item on any emergency power list because smartphones provide communication, emergency alerts, flashlight functionality, and access to information. The minimal power draw means even the smallest generators can charge multiple phones simultaneously with negligible impact on total capacity.
Generator Sizing for a Phone / Tablet Charger
Running a phone / tablet charger by itself requires a generator with at least 32 W of capacity (1 kW), which includes a 25% safety margin. However, you rarely run a single appliance on a generator. When combined with other appliances, the phone / tablet charger contributes 25 W to the continuous running load.
The phone / tablet charger is a resistive load, meaning it uses a heating element or simple electronic circuit rather than a motor. Resistive loads draw the same wattage from the moment they turn on until they turn off, with no starting surge. This makes them the easiest type of appliance to run on a generator. When calculating your total generator load, the phone / tablet charger adds a flat 25 W to your running total with no impact on peak surge calculations. Resistive loads also produce a power factor of 1.0, meaning they use electricity very efficiently with no wasted reactive power.
To determine the total generator size you need, use our interactive calculator to combine the phone / tablet charger with your other appliances. The calculator automatically handles the starting surge calculation and applies the 25% safety margin to give you an accurate recommendation. Alternatively, browse the scenarios below to see common generator setups that include the phone / tablet charger.
Scenarios That Include Phone / Tablet Charger
The following pre-calculated generator scenarios include the phone / tablet charger in their appliance list. Each scenario shows the total generator size needed for all appliances in the set, not just the phone / tablet charger alone. Click any scenario to see the full appliance breakdown.
Tips for Running a Phone / Tablet Charger on a Generator
Running a phone / tablet charger on a generator is straightforward since it is a purely resistive load. There are no special starting procedures or surge considerations. Simply ensure your generator's continuous (rated) wattage exceeds 25 W plus the wattage of all other appliances running simultaneously.
Since the phone / tablet charger draws a constant 25 W whenever it is operating, you can accurately predict generator fuel consumption. At typical generator fuel efficiencies, running the phone / tablet charger continuously adds approximately 0.0 gallons of gasoline per hour to your fuel consumption. If the phone / tablet charger operates intermittently (like a thermostat-controlled heater), the actual fuel impact will be lower.
For sensitive electronic components within the phone / tablet charger, an inverter generator provides the cleanest power output. However, most resistive appliances work fine on conventional generators as well. If you are running the phone / tablet charger along with sensitive electronics like computers, the inverter generator protects all connected devices.
Phone / Tablet Charger Wattage Compared to Similar Appliances
The following table compares the phone / tablet charger to other appliances in the other category. Understanding relative power requirements helps you make informed decisions about which appliances to prioritize on your generator and where you might find opportunities to reduce your total load.
| Appliance | Running Watts | Starting Watts |
|---|---|---|
| Phone / Tablet Charger (this appliance) | 25 W | — |
| Sewing Machine | 100 W | — |
| Clothes Iron | 1,200 W | — |
| Hair Dryer | 1,500 W | — |
| Electric Blanket | 200 W | — |
| Pool Pump (1 HP) | 1,500 W | 2,500 W |
| Hot Tub / Spa | 6,000 W | 7,500 W |
Frequently Asked Questions
How many watts does a phone / tablet charger use?
A phone / tablet charger uses approximately 25 watts of continuous (running) power during normal operation. As a resistive load with no motor, it has no starting surge above its running wattage.
What size generator do I need to run a phone / tablet charger?
To run a phone / tablet charger by itself, you need a generator rated for at least 32 W (1 kW), which includes a 25% safety margin above the running wattage of 25W. However, most people run additional appliances alongside the phone / tablet charger, so your actual generator needs will be higher. Use our calculator to add your other appliances and get a comprehensive recommendation.
Can I run a phone / tablet charger on an inverter generator?
Yes, a phone / tablet charger runs perfectly well on an inverter generator. As a resistive load with no motor starting surge, it is one of the easiest appliances to power with any generator type. The clean sine wave output of an inverter generator is a bonus for any electronic components.