USB Cables & Chargers: How to Choose the Right One

The plain-English guide to USB cables and chargers

USB naming is famously confusing — the same-looking cable can charge at 10 watts or 100, and transfer data at wildly different speeds. Here's what actually matters when choosing a cable or charger.

Connector types you'll still find in NZ homes

Connector Recognise it by Where it's used
USB-C Small, oval, reversible Modern phones (including iPhone 15 onward), laptops, tablets, earbuds — the current universal standard
USB-A Classic flat rectangle Older chargers, car ports, wall sockets with USB, computers
Micro-USB Small trapezoid Older phones, budget gadgets, remotes, e-readers, LED controllers
Lightning Slim, reversible, Apple-only iPhone 5–14, older AirPods and Apple accessories
USB-B / Mini-USB Squarish / small trapezoid Printers, older cameras and audio gear

Since late 2024 the EU has required USB-C on new phones and small gadgets, and the rest of the world — NZ included — has followed the same direction. When buying new accessories, defaulting to USB-C is the future-proof pick.

Charging speed: it's about watts, not just the plug

Charging speed = voltage × current. What you actually need to know:

  • Basic USB-A ports deliver 5–12 W — fine for earbuds, slow for phones.
  • USB Power Delivery (PD) over USB-C is the modern fast-charging standard: commonly 18–100 W, and up to 240 W in the newest PD 3.1 spec. Phones typically draw 18–30 W; laptops 45–100 W.
  • Quick Charge (QC) is a common alternative on USB-A chargers — many devices support both.
  • The device, charger and cable negotiate the fastest rate they all support — the weakest link sets the speed. A 100 W charger won't hurt a phone; the phone simply takes what it needs.

Fast-charging standards at a glance

Standard Connector Typical power Found on
Standard USB USB-A 5–12 W Older chargers, car ports, powerboards with USB
Quick Charge (QC 3.0/4) USB-A / USB-C 18–27 W Android chargers, car chargers
USB Power Delivery (PD 3.0) USB-C 18–100 W Modern phone & laptop chargers
USB PD 3.1 (EPR) USB-C Up to 240 W Newest high-power laptops

What wattage charger does my device need?

Device Typical charge rate Recommended charger
Wireless earbuds, smartwatch 2–5 W Any USB port (see watch chargers for the right cable)
Smartphone 18–30 W 20–30 W PD charger
Tablet 18–45 W 30–45 W PD charger
Thin/light laptop 30–65 W 65 W PD charger + e-marked cable
Performance laptop 65–140 W 100 W+ PD charger + 100 W/240 W cable

Cable wattage matters too

Standard USB-C cables carry up to 60 W (3 A). Cables rated for 100 W+ (5 A) contain an identification chip ("e-marked"). If your laptop charges slowly, an underrated cable is a common culprit.

Data speeds: check the spec, not the shape

Standard Max speed Real-world meaning
USB 2.0 480 Mbps Fine for keyboards, charging, small file transfers — many charging cables are USB 2.0
USB 3.2 Gen 1 (old "USB 3.0") 5 Gbps External drives, webcams
USB 3.2 Gen 2 10 Gbps Fast SSDs, video capture
USB4 / Thunderbolt 40+ Gbps Docks, external GPUs, pro video

Important: a USB-C shaped cable can be any of these internally. A cheap USB-C cable may charge fast but transfer data at USB 2.0 speed — fine for charging, frustrating for backups. Check the listed spec.

How to choose — quick scenarios

  • New phone: USB-C to USB-C cable + a 20–30 W PD wall charger.
  • Laptop that charges via USB-C: PD charger at your laptop's rated wattage (commonly 45–65 W) + a 100 W-rated cable.
  • Car: a dual-port PD adapter charges two devices at speed.
  • Older gadgets: keep a Micro-USB and Lightning cable around — remotes, controllers and LED gear often still use them.
  • Smartwatches: most use proprietary magnetic pucks — see our watch chargers & cables.

Browse our cables, adapters & connectors and chargers & power adapters — stocked in Auckland with fast NZ-wide courier. Need video instead? See HDMI cables & adapters or AV adapters.

Frequently asked questions

Will a high-wattage charger damage my phone?

No. USB PD chargers negotiate with the device and only supply what it requests. A 65 W charger is perfectly safe for a phone that draws 20 W.

Why does my device charge slowly from some cables?

Either the cable is rated below your charger's output (e.g. a 3 A cable with a 5 A charger), it's damaged, or it's a "charge-only" cable with data lines that some devices need for fast-charge negotiation.

Are all USB-C ports the same?

No — USB-C is just the connector shape. Power and data capabilities vary by device. Check your device's specs for its supported wattage and USB generation.

What does "e-marked" mean?

Cables carrying more than 3 A (60 W) must include an ID chip that tells the charger it's safe to send more power. All 100 W and 240 W cables are e-marked.

Can I use my old USB-A charger with a USB-C phone?

Yes, with a USB-A to USB-C cable — it will charge, just usually at slower (non-PD) speeds.

Can't find the exact cable or plug you need? Ask us — tracking down odd parts is what we do.