Qi Wireless Charging Explained

Qi (pronounced “chee”) is why a pad from one brand can charge a phone from another. This page covers how it works, what the speed tiers are, how certification works, and the trade-offs against a cable.

How does Qi wireless charging work?

Wikipedia says Qi devices rely on electromagnetic induction between planar coils. A base station has a transmitting coil that creates an oscillating magnetic field, and the phone has a receiving coil in which that field induces an alternating current. The WPC points to magnetic induction as the basic science behind Qi.

Wikipedia says Qi chargers can be effective over distances up to 4 cm, and that version 1.1 added foreign object detection to prevent heating of metal objects near the transmitter.

What does Qi Certified mean?

Products are tested for safety and interoperability in independent authorized labs before they may show the Qi or Qi2 logo. Only Qi Certified products can display those logos. The WPC offers a searchable database of certified products, so you can check a charger before buying it.

How fast is Qi?

Profile	Power	Source
Baseline Power Profile	5W maximum	Wikipedia
Extended Power Profile	Up to 15W	Wikipedia
Qi2 (Magnetic Power Profile)	15W	WPC
Qi2 25W	Nearly 70% more than Qi2	WPC

These are standard-body ceilings. Your phone and the charger negotiate what they both support, so see Qi2 for the magnetic profiles and the wattage guide for the phone figures.

Is wireless charging less efficient than wired?

Wikipedia says wireless charging is significantly less efficient than wired charging and produces more waste heat. It cites a 2020 analysis in which a wired charge from 0 to 100 percent consumed 14.26Wh, a wireless charging stand used 19.8Wh (39% more), and a misaligned stand used 25.62Wh (80% more). That is one analysis of one stand, not a rule for every charger, but it explains why alignment, and the magnets in Qi2, matter.

Which phones in our library use Qi?

Sixteen phone pages list Qi, 19 list Qi2, and 16 list Apple’s MagSafe. The counts overlap, because many iPhone pages list more than one. Six list no wireless charging at all: the five Galaxy A phones and the Moto G Power. Motorola’s other five phones list wireless charging without naming a standard, so we show it as Motorola states it. Check the phone library for your model.

When did phones start using Qi?

Wikipedia says Nokia first adopted Qi in its Lumia 920 in 2012 and Samsung followed on the Galaxy S3 through an accessory that year. Apple’s iPhone 8, 8 Plus and iPhone X, announced on September 12, 2017, were among the first major iPhones to support it. Qi v2.0 arrived in April 2023, according to Wikipedia, and introduced the Magnetic Power Profile that Qi2 uses.

Wireless charger buying page, Apple hub, Samsung hub, chargers hub.

Frequently asked questions

Q01

Who makes the Qi standard?

The Wireless Power Consortium (WPC) manages Qi, which it says launched in 2010. Wikipedia says version 1.0 was released in July 2010. The WPC is a standards body, so Qi chargers come from many different brands.

Q02

How do I know a wireless charger is Qi Certified?

The WPC says only Qi Certified products can display the Qi or Qi2 logo, and it provides a database where you can search for certified products. Products are tested for safety and interoperability in independent authorized labs first.

Q03

How far away can a Qi charger work?

Wikipedia says Qi chargers can be effective over distances up to 4 cm. It also cites research that misalignment of more than 3 cm can severely lower power transfer, which is why placing the phone squarely on the pad matters.

Q04

How fast is Qi wireless charging?

Wikipedia lists a Baseline Power Profile of 5W maximum and an Extended Power Profile of up to 15W. The magnetic Qi2 profile is rated at 15W, and Qi2 25W, launched in July 2025, adds nearly 70% more power according to the WPC.

Q05

Is wireless charging less efficient than a cable?

Wikipedia says yes. It cites a 2020 analysis in which a wired charge from 0 to 100 percent used 14.26Wh, a wireless stand used 19.8Wh, a 39% increase, and a misaligned stand used 25.62Wh. One test is not every charger, but the direction is clear.

Q06

Which phones were first to use Qi?

Wikipedia says Nokia first adopted Qi in its Lumia 920 in 2012, with Samsung following that year on the Galaxy S3 through an accessory. Apple's iPhone 8, iPhone 8 Plus and iPhone X, announced September 12, 2017, were among the first major iPhones to support it.