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.