All buzzing and rumbling we feel in our smartphones are created by small vibration motors known as haptic actuators. While physical buttons have largely disappeared, active haptics are more prominent than ever, featured in camera shutters, shopping experiences or by language-teaching owls.

Haptics, however is rarely advertised as a feature and is also challenging to compare looking at device specifications. So let’s take a closer look at the current state of haptics in smartphones, investigate how iOS and Android devices differ, and explore what makes a good haptic fidelity.

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Haptic feedback is generated by haptic actuators. These actuators are typically electromagnetic and convert electrical energy into motion by accelerating an internal mass. There are three types of haptic actuators used in smartphones today:

Wideband Voice Coil (VC) actuators: The most advanced and capable type, commonly found in high-end smartphones or game controllers.

Linear Resonant Actuators (LRA): The most common type in modern electronics due to their balance of efficiency, price and fidelity.

Eccentric Rotating Mass (ERM) actuators: The most affordable option, but with limited capabilities compared to VC and LRA actuators

Understanding haptic capabilities

To compare capabilities between different actuators and phone models, we need to shed some light on three essential parameters: Intensity level, frequency bandwidth and response time.

Note: Haptic applications are unique and choosing a suitable actuator requires many more aspects such as the context, size, body position. A generalisation of certain models being universally good or bad is not possible. Visit our haptic Design principles to learn more.

Intensity level: How strong is the signal?
The intensity of the haptic output is largely influenced by the mass of the actuator’s moving part (We are keeping things simple here). A higher mass results in stronger vibrations and improved representation of lower frequencies, allowing designers to create more distinct and contrasting sensations.

Frequency bandwidth: What range of frequencies can be produced?
Each type of haptic actuator has a distinct mechanical structure that affects its ability to produce vibrations at different frequencies:

LRA actuators are optimised to perform at a specific and very narrow frequency range (Resonant frequency) making them highly efficient for certain applications but less versatile overall. It’s like playing a song on a piano using only one key.

ERM actuators produce haptics by spinning an eccentric mass — As the mass spins faster, both the frequency and amplitude of vibrations increase simultaneously. Imagine as you press a key on a piano harder, the notes also get higher in pitch. You could not play a low note loudly or a high note softly because the pitch and volume are linked — Same applies to the ERM.

Wideband VC actuators, as their name suggests, are capable of rendering a wide frequency spectrum. The wider frequency spectrum allows for more nuanced and expressive haptic feedback just like a pianist utilising the complete range of keys. On iOS devices, this spectrum ranges from about 80–230Hz.

Response time: How quickly can the actuator start and stop?
Transients are short haptic pulses that require the actuator to respond very quickly to the incoming signal. To create this effect, the actuator must rapidly accelerate its internal mass for a brief moment and then bring it to rest by reversing the signal (=braking). The faster it can do this, the more precise a transient can be rendered. ERM’s have comparably slow spin-up and spin-down times, making them the least capable when it comes to producing transients such as mimicking mechanical clicks.

Why does it matter?
A capable haptic actuator offers a greater design freedom to craft nuanced feedback. It empowers designers to create signals that complement user interactions, convey a greater sense of realism and utilise subtle differences or distinct patterns to provide an intuitive user experience.
While the actuator plays a main role, it’s important to note that the haptic capability is also heavily influences by the driving electronics, the signal design and physical properties of the device — All need to correlate to provide a high fidelity output.

Haptic capabilities of iOS vs. Android devices

As of 2025, smartphone models are available with all three types of haptic actuators mentioned. Most manufacturers however feature wideband actuators at least in their flagship models: Apple first introduce VC actuators in 2015 (iPhone 6s), Google in 2021 (Pixel 6), Samsung in 2022 (Galaxy S22), OnePlus in 2019 (OnePlus 7).

Since adopting the Taptic Engine in 2015, Apple consistently features the actuator in all iOS devices, independent of the model and price. In contrast, Google differentiates their high-end models and uses LRA actuators in their more budget-friendly “a” series devices. The drawback is a significantly narrower range of experiences, with limited ability to produce lower-frequency “rumbles” or convincing mechanical click sensations.

Mechanical differences
Examining the latest models from Apple and Google reveals that their underlying haptic mechanics have grown more similar over the years. Shown bellow are X-rays of a iPhone 16 Pro Max and Pixel 9 Pro XL. In both devices, the wideband actuator features a mass suspended between two springs, one on each side. Spot a difference in size?

While Samsung and OnePlus employ a similar approach, they position the springs and coils in a different configuration compared to Apple and Google.

Actuator placement

Given that approximately 90% of the population is right handed, one might expect the haptic actuator to be placed on the right side or center of the device. However the most common position is on the bottom left side. This placement likely minimizes interference with the battery, main PCB, and sensitive components like sensors and speakers, as haptic actuators generate magnetic fields. 
It’s worth noting that smartphones are densely packed and rigid structures, allowing haptic signals to propagate effectively throughout the device. As a result, the specific placement of the actuator may have less impact on the overall haptic experience compared to other factors, such as actuator size and type.

Actuator footprint

In 2021, Amir Berrezag and Hansika Jayawardana (part of the former Lofelt team) shared their analysis of the actuator size in Apple iOS versus Android devices. They compared phone models starting with the Apple iPhone 6 over a timespan of 4 years. Two of their findings included a decline in actuator size and a substantial difference between Apple and Android. Four more years have passed since then, let’s take a look where things have led? 

Methodology 
Investigating haptics is challenging since there is no comprehensive source listing haptic parameters. Similar to the original approach by Lofelt, the data was collected from various sources, including manufacturer data-sheets, measurements of replacement parts, device teardowns, and X-ray images. While the height of the actuator was not always available, the approximations provide valuable insights into the overall trend.

Results

The graph below illustrates the ratio of actuator footprint to smartphone footprint (%), with the vertical axis representing the release timeline of the model and the horizontal axis indicating the size ratio. Data prior 2021 is reflecting Lofelt’s publication.

As highlighted above, an increased footprint (= weight in this context) results in an increased intensity output as well as a better representation of the lower frequency spectrum. By considering the size (and mass) of the device, we can calculate the actuator-to-device ratio, which in combination with the actuator type, indicates the expected capabilities of the haptic system. A higher ratio generally translates to better haptic fidelity.

Diminishing size

Back in 2021, Lofelt highlighted the diminishing actuator size in the Apple ecosystem. Taking a closer look at the models that followed, Apple seems to have identified a sweet-spot when it comes to size and performance. While it might look stagnating, there have been many iterations to the mechanical structure of the actuator over the years. When it comes to the difference to variation between the Ultra/ Max and default versions, one can see a declining ratio in the larger models as most of the time the same actuator is equipped.

Averaging the results from 2024 devices and comparing it to models between 2018 and 2020, the actuator/ smartphone ratio indicates a decline in the Apple ecosystem as well as an increase of footprint for Android devices - Still, Android devices average an about 35% smaller actuator size.

Software vs. Hardware

Although the type and capability of the actuator greatly influence the haptic experience, software, signal and electrical components play an equally crucial role. The driver IC converts the digital haptic signal into the electrical current that powers the haptic actuator. Advanced driver ICs not only output the signal but also integrate sensor data to create a closed-loop system. The software framework must also take advantage of advanced drivers and expose parameters for creating complex haptic signals to designers and developers. Apple’s CoreHaptics offers a unified framework across iOS devices, while the Android ecosystem has only recently pushed further to provide means to create haptics across devices.

Conclusion

Haptics in smartphones are more prominent than ever, with capable actuators available across the market. The focus has nowadays shifted towards delivering haptic content that leverages the capabilities of these devices. The primary challenge lies in addressing the wide range of devices with varying capabilities and missing framework support, making it difficult for designers to create consistent haptic experiences. 

At Hapticlabs, we provide intuitive tools that allows you to create custom haptic signals for both Android and iOS devices. Craft unique haptic experiences and test them live on you smartphone or build functional prototypes. Try it now and get buzzing!

Shoutout to the team of DBRAND for granting me permission to use their beautiful x-ray visuals! Link to learn more.