Car chargers can charge some laptops, but not all — it depends on the laptop's power needs and the charger's output
A car charger will charge your laptop only if two things line up: the charger outputs enough power, and your laptop accepts that type of connection. Most car chargers produce 12 to 24 watts of power. Many modern laptops — especially thin models and Chromebooks — need 30 to 65 watts or more. If your charger is underpowered, your laptop will charge very slowly, stay at the same battery level while you use it, or not charge at all.
The connection type also matters. Your car charger needs to match your laptop's charging port. Common laptop ports include USB-C, barrel connectors (the round plug specific to certain brands), and proprietary connectors. A USB-C car charger works with any USB-C laptop, but a barrel connector charger only works with the exact brand and model it was designed for.
Key Takeaways
- Car chargers typically output 12 to 24 watts, while most laptops need 30 to 65 watts or more to charge at normal speed.
- Your car charger's connector type must match your laptop's charging port — USB-C, barrel connector, or proprietary — or it will not fit.
- A low-power car charger may slow-charge a laptop or keep the battery level steady while you work, but will not fully charge a drained battery quickly.
- High-output USB-C car chargers rated 60 watts or higher are most likely to charge modern laptops at a usable speed.
How much power your laptop actually needs
Laptop power requirements vary widely by size and processor. A 13-inch ultrabook or Chromebook might need 30 to 45 watts. A 15-inch laptop with a standard processor typically needs 45 to 65 watts. Gaming laptops and workstations can need 100 watts or more. You can find your laptop's power requirement by looking at the original charger — the wattage is printed on the brick or cable.
A car charger that outputs less than your laptop needs will not damage the laptop, but it will charge slowly or not at all. If you are using the laptop while charging, a low-power charger may not keep up with the power drain, and your battery will drop even while plugged in.
USB-C car chargers and why they are the most flexible option
USB-C is the charging standard for most modern laptops, phones, and tablets. A USB-C car charger can charge any device with a USB-C port, regardless of brand. This makes USB-C chargers more useful than older barrel-connector chargers, which only work with specific laptop models.
When shopping for a USB-C car charger, look for one rated 60 watts or higher if you plan to charge a laptop. A 30-watt USB-C charger will charge a small laptop or Chromebook slowly. A 65 to 100-watt charger will handle most standard laptops at a reasonable speed. Some car chargers have multiple ports — for example, two USB-C ports or one USB-C and one USB-A — which lets you charge a laptop and a phone at the same time, though power splits between them.
Barrel connectors and brand-specific chargers
Older laptops and some current models from Dell, Lenovo, and HP use barrel connectors — round plugs that are specific to each brand and sometimes to each model. A barrel-connector car charger only works if it matches your exact laptop model. You cannot use a Dell barrel charger on an HP laptop, even if the wattage is right.
If your laptop uses a barrel connector, check the original charger or your laptop's manual to find the exact connector size and polarity (which direction the plug goes in). Then search for a car charger with that specific connector. These are less common than USB-C car chargers and may be harder to find.
What happens when you use an underpowered car charger
Using a car charger that outputs less power than your laptop needs will not break anything. The laptop will straightforward charge slowly or not charge at all. If your battery is at 50 percent and you plug in a 24-watt charger to a laptop that needs 65 watts, the laptop may hold steady at 50 percent or drop slowly while you work.
This is actually safer than overcharging — modern laptops have built-in protection that prevents damage from low-power chargers. However, it means the car charger is not practical for your use. If you need to charge your laptop in the car, you need a charger that outputs at least 80 percent of your laptop's rated power.
Alternatives if a car charger will not work for you
If a standard car charger is too weak for your laptop, consider a car power inverter. This device plugs into your car's 12-volt outlet (the cigarette lighter socket) and converts the power to standard 110-volt AC current. You can then plug your laptop's original charger into the inverter, just as you would at home. Inverters come in different wattages — a 150 to 300-watt inverter is usually enough for a laptop charger.
Power inverters are bulkier and more expensive than car chargers, but they let you use your laptop's original charger, which guarantees full power. They also work with other devices that need AC power, like small appliances or power tools.
Another option is a portable power bank designed for laptops. These are large battery packs that store energy and can charge a laptop multiple times. You charge the power bank at home or in the car using a standard charger, then use it to charge your laptop on the road. Power banks are convenient for travel but do not charge as fast as a direct car charger.
How to check if your car charger will work before you buy
Before purchasing a car charger, gather three pieces of information: your laptop's wattage requirement (from the original charger), your laptop's charging port type (USB-C, barrel connector, or proprietary), and the car charger's output wattage and connector type.
Match the connector type first — if the plugs do not match, the charger will not fit. Then compare wattages: the car charger should output at least 80 percent of your laptop's requirement. For example, if your laptop needs 65 watts, look for a car charger rated 50 watts or higher. If you cannot find an exact match, a higher-wattage charger is always safer than a lower one.
Frequently Asked Questions
Will a 30-watt car charger charge my laptop?
It depends on your laptop's power needs. A 30-watt charger works well for small Chromebooks and ultrabooks that need 30 to 45 watts. For larger laptops that need 65 watts or more, a 30-watt charger will charge very slowly or not at all while you are using the laptop. Check your original charger's wattage to be sure.
Can I use a phone charger to charge my laptop?
Only if your laptop has a USB-C port and the phone charger is USB-C. However, phone chargers typically output 18 to 30 watts, which is too low for most laptops. Your laptop will charge extremely slowly or not charge while in use. For practical charging, use a charger rated for your laptop's full power requirement.
What is the difference between a car charger and a power inverter?
A car charger plugs into your 12-volt outlet and outputs low-voltage DC power directly to your device. A power inverter converts 12-volt DC to 110-volt AC, letting you plug in your original charger or other AC devices. Inverters are bulkier but provide full power; car chargers are compact but may be underpowered for laptops.
Can I damage my laptop by using the wrong car charger?
Using a low-power charger will not damage your laptop — it will straightforward charge slowly or not at all. Using a charger with the wrong connector type will not fit. The main risk is using a charger with the wrong polarity on a barrel connector, which could damage the laptop. Always match the connector type exactly before plugging in.
Do I need a special car charger for a Mac laptop?
Modern Mac laptops use USB-C, so any high-output USB-C car charger will work. Older Mac models used proprietary connectors, so you would need a charger designed for that specific model. Check your laptop's charging port to determine which type you need.