Best Portable Charger Under £20 in 2026
Quick Summary
- Best Overall: Anker PowerCore 10000 — Excellent capacity, compact build, and trusted reliability at an unbeatable price.
- Best Budget: INIU 5000mAh Slim Power Bank — Ultra-thin, lightweight, and perfect for a single emergency top-up under £12.
- Best Premium Pick Under £20: Charmast 10400mAh Power Bank — High capacity with USB-C in/out and LED display for the savviest shoppers.
Finding a reliable portable charger without spending a fortune is easier than ever in 2026. Whether you’re a commuter constantly draining your battery on podcasts, a student juggling lectures, or a traveller who can’t afford a dead phone, a good power bank under £20 can be a genuine lifesaver. The budget end of the market has improved dramatically — today’s affordable power banks offer fast charging, slim designs, and enough juice to top up a modern smartphone at least once. In this guide, we’ve tested and reviewed the best options available in the UK right now, covering every type of buyer from the bargain hunter to the heavy daily user.
What to Look For in a Portable Charger Under £20
- Battery Capacity (mAh): The higher the milliamp-hour rating, the more charges you’ll get. A 5000mAh bank gives roughly one full charge for most smartphones, while 10000mAh can manage two or more.
- Charging Speed: Look for at least 10W output for a reasonable charging speed. Some budget banks now support 18W or 22.5W fast charging, which is a real bonus at this price point.
- Port Selection: A USB-C port for both input and output is increasingly important as more devices drop Micro-USB. Having both USB-A and USB-C lets you charge different devices simultaneously.
- Size and Weight: A power bank you’ll actually carry is worth far more than one left at home. Slim, lightweight designs under 200g slip easily into a pocket or small bag without adding bulk.
Comparison at a Glance
| Product | Price | Best For | Rating |
|---|---|---|---|
| Anker PowerCore 10000 | £18 | Everyday reliability & capacity | ★★★★★ |
| INIU 5000mAh Slim Power Bank | £11 | Ultra-portable emergency charging | ★★★★☆ |
| Charmast 10400mAh Power Bank | £19 | High capacity with USB-C & display | ★★★★☆ |
Our Top Picks
Anker PowerCore 10000
Anker is the gold standard in affordable power banks, and the PowerCore 10000 is the reason why. With 10,000mAh of capacity, it can fully charge most modern smartphones twice over. It’s slim enough to fit in a jeans pocket and light enough at just 180g that you’ll barely notice it in a bag. Two USB-A outputs mean you can charge two devices at once, and Anker’s PowerIQ technology intelligently optimises output for whichever device is connected. Build quality is far above what you’d expect for the price, with a premium matte finish that feels reassuringly solid.
Pros
- Excellent 10,000mAh capacity for the price
- Compact, pocket-friendly design at 180g
- PowerIQ smart charging optimises output
Cons
- No USB-C output port on the base model
- Charges itself slowly via Micro-USB input
INIU 5000mAh Slim Power Bank
If you want the cheapest portable charger that’s still genuinely useful, the INIU 5000mAh is a brilliant choice. At under 100g and just 9mm thick, it’s thinner than most smartphones and slips effortlessly into a back pocket. It supports 22.5W fast charging input so it replenishes quickly, and its 12W output is fast enough to give your phone a meaningful top-up in a short time. INIU includes both USB-C and Micro-USB input ports, which adds real versatility. The LED indicator clearly shows remaining battery level, and the build quality for the price is surprisingly respectable. Ideal for light users or as a grab-and-go backup.
Pros
- Incredibly slim and lightweight at under 100g
- Great value — well under £12
- USB-C and Micro-USB input options
Cons
- Only one full smartphone charge in the 5000mAh version
- No simultaneous dual-device charging
Charmast 10400mAh Power Bank
The Charmast 10400mAh punches well above its weight, offering features you’d normally expect at the £25–£35 price point. Most notably, it sports a USB-C input and output alongside two USB-A ports, so it works seamlessly with the latest smartphones, tablets, and earbuds without needing an adaptor. A clear LED percentage display tells you exactly how much charge remains — far more useful than the vague dot indicators found on cheaper rivals. The 22.5W fast charging input means you can top up the bank itself quickly overnight. At around 210g it’s a touch heavier than the Anker, but the extra features more than justify it for regular users.
Pros
- USB-C in and out — future-proof connectivity
- Accurate LED percentage display
- Charges three devices simultaneously
Cons
- Slightly bulkier than competitors at 210g
- USB-C output is limited to 18W rather than 20W
Who Should Buy a Portable Charger Under £20?
A portable charger under £20 is ideal for anyone who finds themselves away from a power socket for several hours at a time. Students heading to university, commuters on long train journeys, festival-goers, and travellers are all perfect candidates. Even if you’re not a heavy smartphone user, having a compact power bank in your bag means you’ll never face the anxiety of a dying battery when you need maps, a contactless payment, or an emergency call. They also make excellent low-cost gifts for practically anyone on your list.
Budget power banks under £20 do have limitations — they’re generally not suitable for charging laptops, and very high-capacity models above 20,000mAh sit out of this price bracket. If you’re a photographer relying on your phone as a primary camera, or you regularly spend multiple days off-grid, you may want to consider investing a little more. But for the vast majority of everyday UK users, the options in this guide will serve you brilliantly without any compromise on safety or reliability.
Final Verdict
You genuinely don’t need to spend a lot to get a capable, reliable portable charger in 2026. Our top pick, the Anker PowerCore 10000, delivers the best all-round experience with proven reliability, solid capacity, and a compact form factor for around £18. If your budget is tighter, the INIU 5000mAh is a brilliant slim option under £12 that won’t let you down. And if you want the most features for your money, the Charmast 10400mAh edges close to £20 but rewards you with USB-C connectivity and a proper display. Any of these three will keep you powered up without draining your wallet.
Frequently Asked Questions
Are portable chargers under £20 safe to use?
Yes, as long as you buy from reputable brands such as Anker, INIU, or Charmast that carry CE and FCC certifications. These safety marks confirm the device has been tested against European electrical standards. Always avoid unbranded power banks with no certifications, as they can pose a genuine fire or overheating risk.
How many times can a 10,000mAh power bank charge my phone?
A 10,000mAh power bank will typically provide between one and a half to two full charges for a modern smartphone with a 4,500–5,000mAh battery. Real-world output is slightly lower than the stated capacity due to energy lost as heat during the conversion process, so expect around 6,500–7,500mAh of usable charge in practice.
Can I take a portable charger on a plane from the UK?
Yes, but only in your hand luggage — power banks are not permitted in checked baggage due to aviation regulations. Most airlines allow power banks up to 100Wh (approximately 27,000mAh at 3.7V) in carry-on bags without special permission. The models in this guide are all well within those limits, so you can travel with them without any issues.
What’s the difference between mAh and watt-hours (Wh)?
mAh (milliamp-hours) measures the raw charge capacity of the battery cells inside the power bank, while Wh (watt-hours) accounts for the voltage and gives a more accurate picture of usable energy. To convert, multiply mAh by the battery voltage (typically 3.7V) and divide by 1,000 — so a 10,000mAh bank equals roughly 37Wh. Airlines and safety regulations use Wh, so it’s worth knowing this figure when travelling.
How long does it take to recharge a portable charger itself?
This varies significantly by model and the charger you use to fill it up. A 10,000mAh bank charged via a standard 5W USB port can take 6–8 hours to fully recharge. However, models with fast-charging input like the Charmast or INIU can recharge in as little as 2–3 hours when paired with an 18W or 22.5W wall charger. Always check the product specifications for input wattage to get the fastest possible recharge times.