Bluetooth is a wireless communication protocol that operates on radio frequencies in the 2.4 GHz spectrum. It’s commonly understood that Bluetooth is meant for short-range data transmission, probably because most of us know Bluetooth as the technology that allows us to connect our phones to our earbuds, headsets, and car stereos.
According to Bluetooth SIG, the special interest group that governs the development of Bluetooth technology, Bluetooth is both a long-range and short-range protocol. But what exactly is this range and why do we need to know about it? Learn more about Bluetooth range and how it works in our guide.
Power-to-Distance Tradeoff
Several factors define the distance of a Bluetooth connection, such as the number of channels, the efficiency of those channels, the quality of transmitter and receiver, the level of antenna gain, and how much the environment degrades the signal.
Generally speaking, low-powered solutions will be short-range, and high-powered solutions can transmit data quite far. Bluetooth generally has a shorter range than WiFi.
Five Bluetooth Classifications
There are five different classifications of Bluetooth, each with different use cases and capabilities. These specifications were established for an intended range of Bluetooth use. However, as technology has improved, so too have the maximum distances that Bluetooth can traverse.
Commercial Bluetooth
Class 1 is the longest-range Bluetooth classification. It supports approximately 300 feet (100 meters) of communicable distance. However, the most potent Bluetooth radios can transmit more than 10 times that distance outdoors.
Class 1 Bluetooth radios are for industrial applications and not used for consumer products. The key to their longer range is the 100mW power rating of Class 1 Bluetooth radios. Commercial Bluetooth connections manage numerous connected devices.
Bluetooth in Consumer Electronics
Most electronic devices with Bluetooth support are Class 2 or Class 3 Bluetooth devices. Consumer products such as Apple and Android smartphones, tablets, and peripherals like wireless earbuds and Bluetooth headsets fall into this category.
Class 2 Bluetooth 4.0 radios officially support data transfer up to 33 feet (10 meters). Meanwhile, Class 3 devices typically have a range of less than 3 feet (1 meter). It’s not uncommon for Class 2 devices to reach 100 feet, but they don’t officially support that range.
In 2017, the Bluetooth SIG introduced the Bluetooth 5.0 specification, which increased the maximum range of Class 2 devices from 33 feet to 800 feet.
Lower Power Draw Means a Shorter Range
The difference between Class 2 and Class 3 Bluetooth radios mostly comes down to power draw. A Class 2 radio can use up to 2.5mW, whereas Class 3 radios pull less than 1mW. You will usually find Class 2 Bluetooth in higher-end smartphones and Class 3 Bluetooth in most wireless accessories, such as a keyboard, wireless headphones, or a wireless speaker.
Years after Class 1 and Class 2 were established, Class 1.5 joined the Bluetooth standard, which offers a mid-range option of up to 65 feet (20 meters).
There is also Class 4 Bluetooth. This is a low-power option, with an even shorter communication distance of fewer than 1.5 feet (0.5 meters).
The Environment Impacts & Bluetooth Range
The theoretical maximum range of different classes of Bluetooth radios is not the only factor that affects the communication range of your devices. Bluetooth is not a line-of-sight wireless technology, which is to say the receiving end does not require an unobstructed path to the transmitter to achieve a strong Bluetooth signal.
Like radio waves, Bluetooth signals can pass through solid objects. However, those objects will reduce the effective range of the signal.
Signal Degradation
Bluetooth connections can pass through solid matter, but not without signal degradation (or path attenuation as it’s known in the business) that reduces data rate and transmission range. Materials like glass, wood, metal, and concrete can alter the signal strength of a Bluetooth connection.
Environmental factors, such as precipitation and humidity, can also impact the radio waves that carry Bluetooth signals.
Hardware Quality Matters
The quality of your hardware will also have a significant impact on your signal range. As mentioned, the transmit power is directly associated with power consumption, which also impacts heat production and battery life.
The receiver sensitivity is also vital for long-range Bluetooth communication. The wireless signal degrades over distance, and a low-sensitivity receiver may have trouble deciphering the information it receives at long range.
Range Estimator
Many factors can affect the performance of a given Bluetooth device, which makes it very difficult to estimate the range you may get from a particular piece of equipment. The Bluetooth SIG put together a handy tool that can help you figure out the estimated range of specific hardware configurations.
Feature photo by Brett Jordan on Unsplash
Adorama's 42West isthe content destination for photographers, filmmakers, audio creatives and all things electronic. Check out our up-to-date editorial features on all the latest gear, how-to's and interviews with today's most relevant industry insiders.
