Buying guide

How many watts do you need to charge your laptop?

There is one number that decides whether a charger is right, and it is not the port count. Start from the brick your laptop shipped with: that wattage is the floor, not the target.

What you are charging	Stock charger	Buy at least	What actually happens
Phone	20–30W	30W	Phones cap out around here. A 100W charger does not charge a phone any faster than a 30W one.
Tablet / iPad	20–30W	30W	Same ceiling as a phone. Wattage beyond this is only useful for the other ports.
13-inch ultrabook, MacBook Air	30–45W	45W or more	30W will charge it, but slowly, and it can lose ground while you work.
14–16-inch pro laptop	65–100W	100W	This is where a 65W charger starts to disappoint: fine while idle, falling behind while compiling or rendering.
Gaming laptop / mobile workstation	120–330W	Keep the original barrel charger	USB-C cannot replace these. Even at the spec ceiling it will not sustain a discrete GPU under load.

Typical ranges by device class. Your own laptop's brick is the authority — the wattage is printed on it.

The four things the box does not explain

Total wattage is shared, not per port

A “65W two-port” charger does not give 65W to each port. Plug in a phone and the laptop typically drops to around 45W. If you need full speed for the laptop, size the charger for everything you will plug in at once — or leave the second port empty.

100W is the old ceiling, 240W is the new one

USB Power Delivery topped out at 100W for years. PD 3.1 raised it to 240W, but both the charger and the cable have to support it — an ordinary USB-C cable will hold you at 60W no matter what the charger can supply.

Airlines count watt-hours, not mAh

Multiply the mAh by the cell voltage (3.6–3.7V) and divide by 1,000. A 20,000mAh bank is about 74Wh and travels fine; a 27,000mAh bank is close to the 100Wh limit most airlines apply without prior approval.

GaN changes the size, not the rules

Gallium nitride lets a charger run cooler and smaller at the same wattage. It is a real benefit for a travel bag. It does not make 45W behave like 100W.

Mistakes we see most often

Buying by port count instead of wattage, then wondering why the laptop charges slowly with the phone attached.
Assuming a power bank rated 30W can charge a laptop that ships with a 96W brick. It will slow the drain, not reverse it.
Pairing a 100W-capable charger with the thin cable that came in a phone box, which quietly limits the connection to 60W.
Reading “fast charge” as a specification. It is a marketing phrase with no fixed wattage behind it.

Now pick one

Every charger review lists the wattage the manufacturer states, and flags where they do not state it at all.

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