Updated October 2026. This page first appeared in 2018 as a survey of what wireless-power companies were claiming. The claims are kept below so you can see how they aged. The useful part comes first: which method is in your phone, what the numbers mean, and how to read the next big promise.
The short answer: every phone, earbud case and toothbrush that charges on a pad uses inductive charging, standardised as Qi. Resonant charging found its home in electric-vehicle pads. Capacitive charging never left the lab. If you are buying a pad today, our Qi2 25 W guide covers the speed you will actually get.
Three ways to move power without a wire
| Method | How it works | Working gap | Where it is used now |
|---|---|---|---|
| Inductive | Two coils; the pad's magnetic field induces current in the phone's coil | A few millimetres | Phones, earbuds, watches, toothbrushes (Qi and Qi2) |
| Resonant | Coils tuned to the same frequency, so power crosses a larger gap | Centimetres to tens of centimetres | Electric-vehicle charging pads (SAE J2954), some industrial robots |
| Capacitive | Electrodes instead of coils; power crosses an electric field | Contact or near contact | Research papers and one 2011 iPad accessory; no mainstream phone |
The 2018 version of this page treated the three as rivals. They never were. Inductive won the pocket because it is cheap and small. Resonance won the garage because a car cannot park within two millimetres of anything.
What is in your phone
Your phone uses the Qi standard from the Wireless Power Consortium. Basic Qi delivers 5 W, the Extended Power Profile allows 15 W, and Qi2, launched in 2023, adds a magnet ring so the coils line up every time. In 2025 the consortium raised the Qi2 ceiling to 25 W, and the first phones to use it shipped that autumn.
Two things the box will not tell you. First, the pad's own adapter sets the ceiling: a 25 W pad on a 20 W brick is a 15 W pad. Our guide to the new EU charger label explains how to read adapter ratings. Second, wireless loses more energy as heat than a cable, and heat is what ages a battery. Our 80% charging guide covers the trade-off.
What happened to the 2018 claims
| Claim in 2018 | Company | What happened |
|---|---|---|
| Inductive pads at 40 W, "90 W on future designs", for laptops | Powermat | Powermat joined the Wireless Power Consortium in 2018 and now builds Qi hardware for others. No mainstream laptop charges wirelessly; USB-C handles that. |
| Resonant car charging "on the market in 2018" at 11 kW | WiTricity | The technology became the SAE J2954 standard in 2020, at up to 11 kW. Factory-fitted wireless charging on cars remains rare; most installations are fleet and retrofit. |
| Capacitive charging at 10 W, heading for phones, cameras and toys | Murata | The 2011 iPad accessory stayed the only consumer product. The Berkeley technical report that described the method is still the clearest explanation of why: it needs large, flat electrodes. |
| A "global wireless charging ecosystem" of resonant pads in furniture and airports | Integrated Device Technology, AirFuel Alliance | IDT was bought by Renesas in 2019. Public resonant pads never appeared; the public pads that exist are Qi. |
| Inductive charging that feeds energy back to the grid | Bosch | Bidirectional charging arrived, but through the cable: vehicle-to-grid and vehicle-to-home use the wired port. |
Four of the five claims were roadmaps, and roadmaps are not products. The one that shipped on time, Powermat's inductive pad, shipped by giving up its own standard and adopting Qi.
How to read the next wireless-power claim
- Transmitter watts. The pad's rating. It is the ceiling, not the delivery.
- Receiver watts. What the phone or car is allowed to draw. The lower of the two numbers wins.
- Wall-to-battery efficiency. The share of mains power that reaches the battery. A vendor who quotes only coil-to-coil efficiency is leaving out the adapter and the electronics.
- Gap and alignment. Every method loses power with distance and offset. Ask at what gap the headline number was measured.
Frequently asked questions
Is wireless charging bad for my battery?
Not by itself. The extra heat is the problem, so keep the pad off a sunny windowsill and take a thick case off if the phone feels warm.
Can I charge a laptop wirelessly?
Not any laptop you can buy from a mainstream maker. The practical answer for laptops is a USB-C charger rated at the laptop's maximum, as the EU charger label now states on the box.
Do I need Qi2 or is Qi enough?
Qi works with every pad. Qi2 adds magnets, which fixes the misalignment that makes old pads slow and warm. If your phone supports Qi2, a Qi2 pad is worth the small premium.
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