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How many watts does your USB-C charger need?

Updated October 22, 2026 · 5 min read

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A USB-C charger has a number on it: 20W, 45W, 65W, 100W. Pick one that is too weak and your laptop charges slowly or not at all. Pick one that is much stronger than you need and nothing bad happens, you just paid for headroom. This guide explains how to choose without guessing.

Start with what your device came with

The fastest answer is on the charger that shipped with your laptop, tablet or phone. The wattage is printed on the adapter. That is the amount the manufacturer designed the device to use, so a charger with the same number or higher will charge it at full speed.

If you no longer have the original, these are common ranges, not rules:

• Phones: around 20W to 45W for fast charging, depending on the model.
• Tablets: roughly 20W to 45W.
• Thin laptops: often 45W to 65W.
• Larger or performance laptops: 90W to 140W or more.

A bigger charger is safe

USB Power Delivery, the standard behind most USB-C charging, works by negotiation. Your device tells the charger how much power it wants and the charger supplies up to that amount. A 100W charger will not force 100W into a phone that only accepts 25W. A smaller charger than the device wants, on the other hand, will usually still work but slowly.

Multi-port chargers share their wattage

Many chargers advertise a total, such as "65W max" across three ports. When you plug in more than one device, that total is split between them, so a laptop that would get 65W alone may get less when a phone is also charging. Check the listing for how the power is divided if you plan to charge several things at once.

The cable matters too

For higher wattages the cable has to be rated for it. Standard USB-C cables typically carry up to 60W. Cables rated for 100W, or 240W under the newer USB PD 3.1 standard, contain a small chip that tells the charger it can handle the current. A good charger on a weak cable will charge slowly.

Power banks and travel

For a power bank, there are two numbers: capacity (mAh) and output (W). Capacity tells you how long it lasts. Output tells you how fast it can charge. Real-world capacity is lower than the label because some energy is lost in conversion, so a 10,000mAh bank is usually enough for around one to two full phone charges.

If you are traveling abroad, a plug adapter changes the shape of the prongs, not the voltage. Most modern phone and laptop chargers accept 100 to 240V, but read the label on yours before you rely on that.

Quick checklist

• Match or exceed the wattage printed on your original charger.
• Use a cable rated for at least that wattage.
• For several devices at once, look at how the ports share power.
• For a power bank, check both capacity and output.

General information based on common USB-C and USB Power Delivery behavior. We have not tested the products above; their details come from Amazon listings. Always follow your device manufacturer's guidance.