What Wattage Power Bank Do I Need?
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Time to read 3 min
Shopping for a power bank and confused by the wattage numbers? You're not alone. Between 10W, 20W, 45W, 65W and 100W models, it's hard to know what's overkill and what will leave you waiting hours for a charge. The short answer: 20W–30W is ideal for phones, 45W for tablets and small laptops, and 65W–100W for full-size laptops. Here's how to work out exactly what you need.
What does wattage actually mean?
Wattage measures how quickly a power bank can deliver energy to your device. It's the combination of voltage and current (volts × amps = watts). A higher wattage means faster charging — but only up to the maximum speed your device can accept. A phone that charges at 25W won't charge any faster on a 100W power bank; it will simply draw the 25W it's designed for.
That means there's no harm in buying more wattage than you need. The real problem is buying too little: pair a laptop with a 10W power bank and it may charge painfully slowly — or not at all while in use.
Power bank wattage by device
Smartphones: 20W–30W
Most modern smartphones fast-charge at between 18W and 45W. A power bank with a 20W–30W USB Power Delivery (PD) output will take the majority of phones from empty to around 50% in 30 minutes. If you have a flagship phone with faster charging support, a 45W output will make the most of it.
Wireless earbuds and smartwatches: 5W–10W
Small accessories draw very little power, so any power bank will do the job. Wattage isn't the deciding factor here — size and portability are.
Tablets: 30W–45W
Tablets have bigger batteries than phones and benefit from more headroom. A 30W output is the practical minimum for an iPad or Android tablet; 45W will charge larger pro-model tablets at full speed.
Laptops: 45W–100W
This is where wattage really matters. Check the wattage printed on your laptop's original charger and match or exceed it:
- Ultrabooks and small laptops (MacBook Air, most 13" Windows laptops): 45W–65W
- Mid-size laptops (MacBook Pro 14", 15" Windows laptops): 65W–96W
- Performance and gaming laptops: 100W+ — and note that some gaming laptops can't be charged over USB-C at all
If the power bank's output is well below your laptop's charger rating, the battery may still drain while you work, just more slowly.
Don't forget the cable
A fast power bank is only as fast as the cable connecting it. USB-C cables are rated for different power levels — typically 60W, 100W or 240W. Using a 60W-rated cable with a 100W power bank caps your charging speed at 60W. If you're charging a laptop, use a cable rated for at least the power bank's maximum output. Our range of USB-C cables lists the wattage rating on every product.
Wattage vs capacity: two different things
It's easy to mix these up:
- Wattage (W) = how fast the power bank charges your device
- Capacity (mAh) = how much charge it holds
A 20,000mAh power bank with a 10W output holds plenty of energy but delivers it slowly. A 5,000mAh bank with a 30W output charges quickly but won't refill your phone twice. For most people, the sweet spot is a 10,000mAh capacity with a 20W–30W output — enough for two phone charges at fast-charge speeds.
Quick reference table
| Device | Minimum output | Recommended output |
|---|---|---|
| Earbuds / smartwatch | 5W | 10W |
| Smartphone | 18W | 20W–30W |
| Tablet | 30W | 45W |
| Small laptop | 45W | 65W |
| Full-size laptop | 65W | 100W |
Frequently asked questions
Can a power bank have too much wattage for my phone? No. Your device controls how much power it draws, so a high-wattage power bank is safe with any phone. You're paying for headroom you may not use, but nothing will be damaged.
Why is my power bank charging my laptop so slowly? Usually one of three things: the power bank's output is lower than your laptop's charger rating, the cable isn't rated for enough wattage, or you're using a USB-A port instead of the USB-C PD port.
What does PD mean on a power bank? USB Power Delivery — the universal fast-charging standard used by phones, tablets and laptops over USB-C. For anything bigger than earbuds, PD support is worth having.
How is wattage split across multiple ports? Most multi-port power banks share their total output. A 65W bank charging two devices might deliver 45W + 20W. If you need full speed, charge one device at a time.
The bottom line
Match the wattage to the biggest device you'll charge: 20W–30W for phones, 45W for tablets, 65W–100W for laptops — then choose the capacity based on how many charges you need between plug sockets. Browse our full range of power banks with wattage and capacity listed on every model, or pair one with a USB-C cable rated to keep up.
