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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 how we reach a score, where our information comes from, and where the limits of our process lie.

Methodology Updated 28 September 2026
How we test and score wall chargers and portable chargers at SmartGadgetKit: two reviewers comparing GaN wall chargers, portable chargers and cables against four criteria

Our Method

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 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 what sits behind a number.

We would rather be open about our method than dress it up.

What hands-on means here

We do buy or source some of the products we write about and live with them: through an airport, across a hospital shift, over a working week. Those units give us our notes on size in a bag, warmth in the hand, how the cables behave and what wears thin after a month.

That is real-world use, not measurement, so it never stands in for a lab figure. Where one of us has used a product first hand, the review says so and names the person. Where we have not, the review says that too, and every number on the page is credited to the independent source it came from.

Transparent Scoring · Independent Sources · No Lab Claims · Four Criteria · Half-Point Steps · Open Method · Transparent Scoring · Independent Sources · No Lab Claims · Four Criteria · Half-Point Steps · Open Method · Transparent Scoring · Independent Sources · No Lab Claims · Four Criteria · Half-Point Steps · Open Method · Transparent Scoring · Independent Sources · No Lab Claims · Four Criteria · Half-Point Steps · Open Method ·

Evidence Hierarchy

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.

01

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.

02

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.

03

Independent testing

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, not fixed: we add or change sources as the right evidence appears.

04

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.

Charger Scoring

How we score GaN chargers

You can see these scores applied across a whole category in our best GaN charger roundup. 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 Speed8.0
Portability9.0
Travel Versatility7.5
Value for Money8.5
Averaging 8.0, 9.0, 7.5 and 8.5 gives 33.0 ÷ 4 = 8.25, rounded to 8.5 / 10

Portable Charger Scoring

How we score portable chargers

Portable chargers use the same four criteria and the same averaging method, adapted to what matters when the battery, rather than the wall outlet, is the source of power. The worked results sit in our best power banks roundup.

Portable charger 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 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 the headline price alone.
Overall score = average of the four marks, rounded to the nearest half point.

A worked example

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

Charging Speed7.5
Portability7.0
Travel Versatility8.0
Value for Money8.5
Averaging 7.5, 7.0, 8.0 and 8.5 gives 31.0 ÷ 4 = 7.75, rounded to 8.0 / 10

Score Bands

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.

Commitments

What we do not do

Being clear about our limits is part of being trustworthy.

We do not run first-party laboratory tests

We use some of this kit in normal life and report what that is like, but 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 We Are

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. There is more on who we are and how the site is funded on our about page. Journalists will find press and media information on a page of its own.

Alisdair
Lead Reviewer & Editor

Alisdair 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, Alisdair 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 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.

Behind every score

Two perspectives on every product. One technical, one everyday. That is how we keep our reviews honest.

Alisdair, SGK author
AlisdairNetwork engineer, 9 years
Darleene, SmartGadgetKit contributor
DarleeneNurse, professional sceptic
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