Buying a power bank is confusing because mAh tells you capacity, but watts (W) tells you how much power it can deliver—especially important if you’re choosing a power bank for a laptop.
If you’re trying to decide what watt power bank do I need for a laptop (or whether 45W, 100W, or 145W is right), this guide makes it simple—plus includes UK travel tips and the most common reasons fast charging doesn’t work.
At a glance: what watt power bank do you need?
| What you charge | Recommended watts | Why |
|---|---|---|
| Phone (iPhone / Android), earbuds | 20W–45W | Fast, compact, great daily carry |
| iPad / tablet, Nintendo Switch | 30W–45W | More headroom for faster top-ups |
| USB‑C laptop (light use) | 65W–100W | Stable laptop charging via USB‑C PD |
| USB‑C laptop (heavier use) + multi-device charging | 100W–145W | More headroom when charging two devices |
what watt power bank do i need for a laptop is the right question to ask whenever you plan to charge a MacBook, Windows laptop, or handheld gaming device from a power bank.
Watts vs mAh: what’s the difference?
- mAh (milliamp hours) = how much energy is stored (how many recharges you can get).
- Watts (W) = how much power can be delivered at once (how fast it charges, and what devices it can run).
A high-capacity power bank with low watts can still feel slow—especially on newer USB‑C devices.
Step 1 — Choose wattage based on your device
If you mainly charge a phone (including iPhone 15/16 USB‑C)
Most iPhones peak around 20–27W for fast charging, so you don’t need 100W+ for iPhone speed. Higher wattage helps most when you charge multiple devices.
Best pick: a compact 45W power bank (fast, pocket-friendly).
Recommended: Baseus 45W Mini Power Bank 10,000mAh (built‑in USB‑C cable)
If you need a power bank for a laptop (MacBook/USB‑C Windows)
This is where watts matter most. Many laptops need 45W–100W depending on the model and what you’re doing (browsing vs creative work).
- 100W power bank = the practical laptop-capable choice for most USB‑C laptops.
- 145W power bank = for heavier loads, faster charging, or charging multiple devices at once.
Recommended: Baseus 100W Power Bank 20,000mAh (PD fast charging)
Power-user option: Baseus 145W Power Bank 20,000mAh (built‑in 100W retractable USB‑C)
Step 2 — Are you charging one device or two?
If you often charge two devices at once (e.g., phone + laptop), higher wattage helps keep charging stable—especially when one device is a laptop.
When people say “my power bank says fast charging, but it’s slow”, it’s usually because power is being shared across ports, the cable can’t handle the wattage, or the device negotiates a lower charging profile.
UK travel tip: are 20,000mAh power banks allowed on planes?
Airline rules are usually based on Watt-hours (Wh), not mAh. Many airlines allow power banks up to 100Wh in carry-on (always check your airline).
A typical 20,000mAh power bank is often under 100Wh, but you should verify the Wh rating printed on your power bank label.
Tip: Airline limits are usually stated in Watt-hours (Wh). For a quick reference on portable battery rules, check your airline and the UK Civil Aviation Authority guidance.
UK Civil Aviation Authority: items allowed in baggage
FAQ
What watt power bank do I need for a laptop?
As a general guide, choose 65W–100W for most USB‑C laptops, and consider 100W–145W if you charge a laptop while using it heavily or charging a second device at the same time.
Does a higher watt power bank charge my iPhone faster?
Not necessarily. iPhones have a maximum charge rate; higher wattage mainly helps with headroom and charging multiple devices.
Why isn’t my power bank fast charging?
Common causes: the cable can’t support the wattage, you’re using the wrong port, the phone is too hot, or the device doesn’t support the negotiated fast-charge profile.
Do I need 20,000mAh or 10,000mAh?
10,000mAh is ideal for pocket carry. 20,000mAh is better for travel, multiple charges, or laptop use.
Recommended Baseus power banks (UK)
Browse our collection here: Baseus Power Banks