How We Test and Score

How we test and score products is the same wherever you shop, whether in the UK, mainland Europe or the United States. This page explains exactly how we reach a score, where our information comes from, and where the limits of our process lie. We would rather be open about our method than dress it up.

The honest version first

We do not run our own laboratory tests. We do not own a bench full of wattmeters, thermal cameras and load testers, and we are not going to pretend otherwise. What we do is read the evidence carefully, check it against the manufacturer’s own figures and the live retail listing, and turn it into a clear, repeatable score.

That means our value to you is not “we plugged it in once and here is our hot take”. It is the opposite: we gather independent testing from people who do own that equipment, cross-check it against the official specifications and the current Amazon listing, and weigh it all against price and real-world use. When the published evidence disagrees with a manufacturer’s claim, we tell you. When we cannot verify something, we say so rather than guess.

We think being upfront about this makes our scores more trustworthy, not less. You can see exactly what sits behind a number.

Where our information comes from

We work from a clear hierarchy of evidence. Higher tiers carry more weight, and a claim only earns a place in a review once it holds up across the sources we can check.

Manufacturer specifications. The official product page is our baseline for wattage, port layout, dimensions, weight, voltage range and warranty. These are the figures the maker is willing to stand behind.
Verified retail listings. We confirm the exact model, current configuration and availability against the live Amazon listing before any product appears in a review. If we cannot link a product cleanly, it does not go in.
Independent testing and established technology publications. For real-world performance, charging speed under load, efficiency and heat, we rely on outlets and labs that test hardware hands-on, such as iMore, How-To Geek, ChargerLab, Digital Camera World and Windows Central. This list is illustrative rather than fixed: we add or change sources as the right evidence appears, and we always favour independent, hands-on testing over marketing copy.
Our own judgement. Where published evidence is thin, we say so plainly and fall back on documented reasoning, never on invented figures.

If a performance figure cannot be traced to a named, checkable source, it does not appear as a fact in our reviews.

How we score GaN chargers

We score every GaN charger against four criteria. Each is marked out of ten, in half-point steps, and the four marks are averaged to produce the overall score. No criterion is weighted more heavily than another, so the overall figure is a simple, transparent average.

GaN charger scoring rubric

1. Charging Speed / 10

Total and per-port wattage, USB Power Delivery and PPS support, and how quickly the charger tops up reference devices such as a phone and a laptop. We also look at whether full speed holds up when several ports are in use at once.

2. Portability / 10

Weight and packed size measured against output, folding prongs, and how comfortably the charger fits in a bag or pocket. A high wattage in a small, light body scores well here.

3. Travel Versatility / 10

Wide-voltage support (100 to 240V), plug type and whether interchangeable or adapter-friendly heads are available, and the port mix. We reward chargers that can run a phone, laptop and earbuds together and that suit travel across the UK, Europe and the United States.

4. Value for Money / 10

Price against output, port count and build quality, compared with directly competing chargers, plus warranty length and the maker’s track record for reliability.

Overall score = average of the four marks, rounded to the nearest half point.

A worked example

The figures below are illustrative, used only to show the method. Take a hypothetical two-port GaN charger rated at 65W total, weighing 112g, with folding UK prongs, wide-voltage support and one USB-C plus one USB-A port.

Charging Speed: 65W comfortably fast-charges a laptop or a phone, but output is shared when both ports are busy. We might mark this 8.0.
Portability: light and pocketable for its output, prongs fold flat. 9.0.
Travel Versatility: wide-voltage and dual-port, but only one USB-C limits simultaneous fast charging of two modern devices, and there are no interchangeable plug heads. 7.5.
Value for Money: competitively priced against similar 65W units with a solid warranty. 8.5.

Averaging 8.0, 9.0, 7.5 and 8.5 gives 33.0 divided by four, which is 8.25, rounded to an overall 8.5 out of 10.

How we score power banks

Power banks use the same four criteria and the same averaging method, adapted to what matters when the battery, rather than the wall socket, is the source of power.

Power bank scoring rubric

1. Charging Speed / 10

Output wattage and USB Power Delivery support, how fast it charges the devices you carry, how quickly the bank itself recharges, and whether pass-through charging is supported.

2. Portability / 10

Weight and size against capacity, the capacity-to-weight ratio, and whether it is genuinely pocketable or strictly a bag item. A bank that carries a lot of charge without the bulk scores well.

3. Travel Versatility / 10

Capacity in mAh and watt-hours, airline carry-on compliance (most airlines cap cabin batteries at 100Wh, roughly 27,000mAh), the number and mix of ports, and useful extras such as built-in cables or wireless charging. We frame this for travellers across the UK, Europe and the United States.

4. Value for Money / 10

Price against usable capacity and output, compared with competing banks, plus warranty and the maker’s reliability record. We look at cost per watt-hour, not just the headline price.

Overall score = average of the four marks, rounded to the nearest half point.

A worked example

Again, illustrative figures only. Take a hypothetical 20,000mAh power bank (around 74Wh) with 30W USB-C output, weighing 350g, one USB-C and one USB-A port, and no built-in cable.

Charging Speed: 30W fast-charges a phone and trickle-charges a small laptop, and the bank recharges at a reasonable rate. 7.5.
Portability: pocketable but noticeably heavy for the capacity. 7.0.
Travel Versatility: well under the 100Wh airline limit, two ports, but no built-in cable or wireless pad. 8.0.
Value for Money: strong cost per watt-hour against rivals. 8.5.

Averaging 7.5, 7.0, 8.0 and 8.5 gives 31.0 divided by four, which is 7.75, rounded to an overall 8.0 out of 10.

How the four scores combine

The overall score is always the straight average of the four criterion marks, rounded to the nearest half point. We never set a separate top-line number by feel, so the overall figure can always be checked against the four parts. The bands below show what a score signals at a glance.

9.0 to 10

Outstanding. Best in class on this criterion, with little to fault.

7.5 to 8.5

Very good. Strong performer with only minor trade-offs.

6.0 to 7.0

Solid. Does the job well, with clear compromises worth knowing.

4.0 to 5.5

Mixed. Workable for some buyers, but better options usually exist.

Below 4.0

Weak. Falls short on this criterion and hard to recommend.

What we do not do

Being clear about our limits is part of being trustworthy.

We do not run first-party laboratory tests. Performance figures always come from named, independent sources, never from claims we cannot back up.
We do not accept payment to change a score. SmartGadgetKit earns commission when you buy through some of our links, at no extra cost to you, but that never alters a rating or a recommendation. Our affiliate disclosure explains this in full.
We do not list a product we cannot verify. If we cannot confirm the model and link it to a live retail listing, it stays out of the review.
We do not invent specifications. Where evidence is missing, we say so rather than fill the gap with a plausible-sounding number.

Who writes and reviews

SmartGadgetKit is written by people with complementary backgrounds: one technical, one everyday. That combination is deliberate, because the best charger on paper is not always the easiest one to live with.

Alan

Lead reviewer and editor

Alan is a network engineer with nine years in the field, which means he reads a spec sheet the way most people read a menu. He handles the technical side of every review: making sense of wattage and Power Delivery profiles, checking manufacturer claims against independent testing, and deciding how each criterion is scored. If a number does not add up, Alan is the one who notices.

Darleene

Everyday-use reviewer

Darleene is a nurse who lives the way most of our readers do: long days, a bag full of devices that all need charging, and no patience for jargon. She brings the everyday lens to every review, asking whether a charger is genuinely easy to use, light enough to carry and worth the money for a normal person rather than a spec enthusiast. If it would not pass muster on a busy shift or a family holiday, she will say so.

Have a question about how we reached a particular score? We are always happy to show our working.