A USB hub is a power budget, so read the wattage first

Quick answer: Buy a hub with its own power input, not one that lives off your laptop's port. Make sure the charger you plug into it's at least as strong as your laptop's original. If you only need a keyboard and a mouse, ignore all of this and buy whatever's cheap.

The backup that kept vanishing

A guy I know ran his weekly backup through a seven-port hub with no power cord. Every Sunday the external drive would start, click, and drop off the screen halfway through. He blamed the drive. He bought a new drive. Same click.

The drive was fine. The hub was splitting one laptop port's worth of power seven ways, and a spinning drive wants a gulp of current the moment it spins up. The hub couldn't supply it, so the drive gave up.

That's the whole subject. A hub doesn't make power. It shares it.

The numbers behind the plastic

A basic USB-A port is built to deliver 2.5 watts under the old USB 2.0 standard, and 4.5 watts under USB 3.0. A USB-C port can offer 15 watts by default. With USB Power Delivery, the same connector can go up to 100 watts, and newer cables and chargers push past that.

Your phone, in a hurry, wants a good deal more than 4.5 watts. A laptop wants dozens.

Now picture a hub plugged into one laptop port. Everything on that hub, the drive, the webcam, the phone, the keyboard dongle, pulls from that single supply. The laptop will only give up so much, and it's guarding its own battery while it does.

That's a bus-powered hub. It's fine for light things. It's the wrong tool for anything hungry.

A self-powered hub has its own wall adapter or accepts a charger through a USB-C port. The ports draw from that supply, not from your laptop. This is the kind that "actually powers what you plug into it."

What to look for on the box

Ignore the port count first. Find these instead.

• A power input. A barrel jack or a USB-C port labeled for power in. No input, no budget. It's bus-powered, whatever the marketing says.
• Power Delivery passthrough, with a wattage. If the hub charges your laptop through a single cable, it needs a stated passthrough number. Look for something at or above your laptop's original charger. A 65-watt laptop on a 60-watt hub will charge slowly or not at all under load.
• The hub keeps a slice for itself. Many hubs with passthrough hold back some wattage for their own ports and electronics. A 100-watt charger doesn't mean 100 watts reaches your laptop. If the spec sheet says 85 or 90 to the host, believe it, and size your charger to match.
• The charger in the box, or a clear recommendation. A hub with a power input and no stated charger requirement leaves you guessing. Skip it.
• Port speeds that match your gear. A 5Gbps port is plenty for a backup drive and a webcam. A 10Gbps port matters when you're moving big video files to a fast SSD.

The cable is half the story

The best hub in the world won't deliver 100 watts through a cable that can't carry it. USB-C cables aren't all alike. Anything above 60 watts needs a cable rated for 5 amps, and those carry a small chip that says so.

If a laptop charges slowly on a hub that should be fast, swap the cable before you blame the hub. A cable that came free with a pair of earbuds is the usual culprit.

Keep the short, thick, honest cable that came with your charger. Label it with a strip of tape. People throw these away, then spend an hour wondering why the laptop won't charge.

Spinning drives, SSDs and the one place to be stubborn

External drives come in three kinds and they behave differently.

• Solid-state drives sip power. A hub handles them easily.
• Small portable hard drives spin a platter and draw more, especially at startup. They're the ones that click and disappear on weak hubs.
• Desktop hard drives with their own wall adapter don't use the hub for power at all. They only borrow it for the data link, which is fine.

If you keep your photos and documents on a portable spinning drive, connect it to a powered hub or straight into the laptop. Not through the budget hub. If the drive's holding the only copy of something you'd grieve losing, back it up properly and stop trusting a dongle with it.

Troubleshoot it in two minutes

When something acts up on a hub, run the test before you spend a dime.

1. Plug the problem device straight into the laptop. If it works, the hub's your problem.
2. Unplug everything else from the hub and try again. If it works alone, you've exceeded the budget.
3. Try a different cable. Then a different port on the hub.
4. Check the symptoms. A drive that clicks and drops is a power shortage. A phone that crawls along on a charge is the same thing. A keyboard that stutters when the webcam fires up is usually the same thing too.
5. If the wireless mouse lags, move its little receiver away from the hub, or plug it into a USB 2.0 port or a short extension cable. Fast USB 3 ports are known to interfere with 2.4GHz wireless dongles, and it can look exactly like a dying mouse.

Be honest about the trade-off. Powered hubs cost more, take another outlet, and add a brick to your bag. For a laptop that lives at a desk, that's nothing. For a travel kit, a small bus-powered hub for a flash drive and a card reader is perfectly reasonable. Just keep your phone charging off the wall.

What I'd buy and what I'd skip

Buy a self-powered hub with a stated passthrough wattage that covers your laptop, a short list of ports you'll actually use, and a charger you already own that's strong enough. If you have a desk, think about one dock-style unit that stays put and takes a single cable to the laptop. It's the cleanest setup, and it tends to be the most reliable one too.

Skip the ten-in-one dongle with a hundred reviews and no wattage printed anywhere on the page. If the seller won't tell you what it delivers, it's not telling you because the number is bad.

Skip the seven-port bus-powered stick for anything that spins, charges quickly or records video.

Keep the cheap little hub in a drawer for the day you need to read a memory card at a friend's house. It's good at that.

And write the wattage on the hub's underside with a marker. In a year you'll have six chargers in a drawer and no memory of which one belongs to it. Your future self will thank you, and so will the drive.