If you’re concerned about the level of electromagnetic radiation (EMR) exposure you’re subjected to daily, well, you’re in great company. There are lots of folks out there who want to know how to measure EMR but don’t have the slightest clue how to how to go about it.
Purchasing a meter and detector is a great first step. But, if you don’t understand the units for measuring, then it’s all a zero-sum game.
By the end of this guide, you’ll have a firm grasp on how to measure the various kinds of electromagnetic field (EMF) radiation, the units used to measure them, as well as, what constitutes a dangerous reading. Without further ado, it’s time to jump right in.
How to Measure EMF Radiation: The Basics
Before getting into the units for measuring EMF radiation, it’s important to have a general overview of what exactly it is in the first place. An EMF is essentially a physical field that’s produced by an electrically charged object. It is broadly classified into three major categories:
- Electric fields
- Magnetic fields
Exposure to EMF radiation over sustained periods has long-lasting adverse biological effects on the human body. You’ll be surprised by the number of ways you’re exposed to EMF radiation in your day-to-day life.
For instance, the smartphone or PC you’re reading this guide on is emitting radiation. If you heated some leftovers in your microwave, you were exposed to radiation. There’s no escaping it. Ultimately, what matters is that you’re not exposing yourself to high amounts of it over long periods.
EMF is often measured by its strength and frequency. So if you come across terms like ELF (Extremely Low Frequency) or UHF (Ultra High Frequency), they simply refer to the particular region of the EM spectrum that the radiation falls in.
Understanding the Units of Measuring EMF Radiation
When it comes to measuring EMF, there are two major things you need to keep in mind: The frequency of the EMF and the strength of that particular frequency.
1. Frequency of EMF Radiation
The unit for measuring EMF radiation is Hertz, commonly abbreviated as Hz. It is a measure of the number of complete wave cycles per second. So, depending on where you live, for instance, you might measure radiation and find that the electricity that powers your home ranges between 50Hz and 60Hz.
Say, for instance, that you’re in your car jamming to music from your favorite radio station – 98.4 FM. This means that it’s broadcast signals operate on the 98.4 MHz (MegaHertz) band which is equivalent to 98,400,000 hertz.h
Most of the devices that connect to cell towers, or use Wi-Fi to receive and transmit information, usually operate in the GigaHertz (GHz) frequency range. These include familiar electronics like PCs, Android- or iOS-powered devices.
So, if your phone is 4G or 5G enabled, it simply means that it’s broadcasting and transmitting information on a 4 GHz or 5 GHz frequency, respectively.
The chart below displays some of the different services you enjoy and their respective frequencies:
|50 – 60 Hz
|Electrical power in buildings and electrical appliances
|3 – 30 kHz
|535 – 1700 kHz
|88 – 108 MHz
|800 – 940 MHz
|Cellular and cordless phones
|WLAN and Bluetooth
|3 – 30 GHz
|Radar and data transmission
|38.6 – 40 GHz
|High-speed data links
|2483 – 2500 MHz
|Satellite phone downlinks
|54 – 806 MHz
2. Strength of EMF Radiation
When you hear discussions revolving around the dangers of EMF radiation, they are essentially referring to its strength. The most common units used to measure this includes Volts, Watts, and Gauss.
The preference for one unit over the other depends on several factors, such as the type of EMF radiation you’re measuring, the medium, the frequency of the given radiation, and the specific part of the world you’re in.
The next section looks at what units of measurement you should expect with regard to the three different types of EMF radiation.
Radio-Frequency Radiation Units of Measurement
Right off the bat, it’s important to bear in mind that radio-frequency radiation consists of both magnetic and electric frequency components. For this reason, the strength of EMF radiation is expressed in terms that are specific to each of the two components.
The electric portion is given in terms of volts per meter (V/m). The magnetic portion, on the other hand, is expressed as amperes per meter (A/m).
When measuring the radio-frequency, the following units also come into play:
- milliWatts per square meter (mWm²)
- microWatts per square centimeter (µW/cm2)
- microWatts per square meter (µW/m2)
“µW” refers to “microWatts,” whereas “mW” refers to milliWatts. The difference between each of the three all boils down to conversion. Bear in mind that:
- 1 μW/cm² = 10,000 μW/m² = 10mW/m²
- 1W/cm² = 1000 mW/cm² = 1000,000 µW/cm²
- 1 W/m² = 1000 mW/m² = 1000,000 µW/m²
If you can’t remember how to go through the different conversions, there are lots of online conversion calculators available to take a load off.
Power Density of Radio Fields
When radio-frequency waves are generated by an antenna, they exhibit different properties at various distances from the source. The propagation paths of radio-frequency waves consist of: The near field, the intermediate field, and the far-field.
The near field refers to the EMF that exists from the RF source extending over a distance of one wavelength. The intermediate field extends from the end of the near field to the beginning of the far-field. The far-field refers to the EMF located well beyond the near field.
To accurately measure the power density of EMF radiation, it must be measured from the far-field. This is because taking precise measurements from the near field is difficult due to the varying impedance of air.
Power density is expressed in terms of power per unit area, for instance, milliWatts per square centimeter (mW/cm2).
What Is the Best Unit for Measuring Radio-Frequency Radiation?
There’s no definitive answer to this question. However, if you’re looking to protect yourself against EMFs, then the recommended unit of measurement would be volts per meter (V/m). There are two main reasons for this.
First, if you don’t have a scientific background, V/m is fairly straightforward to understand. It’s the easiest way to measure the pulsing effects of radio-frequency radiation, which is considered by most people to be the most detrimental form of EMF.
Second, and equally as important, most EMF meters give their measurements in V/m. So, it would be quite pointless to measure EMF radiation in one unit and then go through the hassle of converting the readings to establish whether they are within acceptable levels. However, if you have to, here’s how to go about it.
Converting W/m2 to V/m
To convert volts per meter (V/m) to watts per square meter (W/m2) apply the following formula:
V/m = (W/m2 x 377)1/2
To convert watts per square meter (W/m2) back to volts per meter (V/m) apply the following formula:
W/m² = (V/m)² / 377
Now that that’s out of the way, this next section looks at magnetic fields.
Magnetic EMF Radiation Units of Measurement
Measuring magnetic fields is a more straightforward process than its radio-frequency counterpart. The units of measurement used are Gauss or Tesla, depending on which region of the world you’re in. Gauss is commonly used in the US whereas a large portion of the rest of the world uses Tesla.
It is common knowledge that even a seemingly weak magnetic field radiation can have adverse effects on human health. So, you’ll often find these units quoted in “Milli” and “Micro,” that is, milliGauss (mG) and microTesla (μT), respectively.
Converting Magnetic Field Units
The conversion of magnetic field units is a lot easier than that of radio-frequency units of measurement. Here’s how to go about it:
1 mG = 0.1 μT
1 μT = 10 mG
Electric EMF Radiation Units of Measurement
The process of measuring the strength of electric fields is pretty much the same as that of the radio-frequency portion covered in the earlier section. The difference comes in the scale of the measurement used.
For instance, to measure the radio-frequency EMF radiation coming to or from your cell phone, you would typically be in the GigaHertz (GHz) realm like 4G or 5G. If you measure the electric fields in your office or home, on the other hand, you would be in the 50 to 60 Hz ballpark.
How to Measure EMF Radiation
A great EMF meter is one that can measure all the different types of radiation – that is Radio-frequency, magnetic field, and electric field. Regardless of the device, you’re using the general procedure of measuring EMF radiation remains the same. Here are the practical steps to follow to get the best results:
1. Do a General Sweep of the Area
The first thing you’ll need to do is to take a general survey of the area you want to scan with your EMF radiation meter. Start with one room and work your way through the house, office, or whichever other space you’re surveying.
It’s important to have a pen and a notebook close at hand to record the EMF readings. To begin, flip your EMF meter to the field marked “magnetic field.” This is a great starting point since magnetic fields are usually generated by nearly every electronic device you’ll have in your space. You’ll be surprised by the amount of radiation your PC emits.
Next, you want to hold out the EMF meter in front of you and slowly walk forward while moving it back and forth.
2. Look Out for a Radiation Source
As you sweep the device back and forth, keep an eye on the display. Note any spikes in the reading, indicating that the amount of radiation is higher than usual. Most EMF meters usually beep faster as the level of radiation increases. The idea is to use the readings to identify where the radiation is coming from. So move in the direction that indicates high emission.
Once you pinpoint the source, move around it and record the average readings in your notebook. If the device whose readings you’re taking doesn’t support any wireless connectivity, then all you need to measure is its magnetic and electric field radiation.
You can then continue doing a sweep of the remaining area and indicating any unusual readings before moving on to another area of the premises. These records will come in handy later when trying to find ways to eliminate your overall EMF radiation exposure and lower any health-related risks you might be facing.
3. Consider Where You Spend a Large Portion of Your Time
The adverse effects of EMF radiation on an individual’s health don’t manifest immediately. It is cumulative. This means that your risk of developing radiation-related ailments increases with continued exposure throughout your lifetime.
For this reason, you need to be mindful of the places where you spend a large portion of your time and measure the amount of radiation in those areas. Some starting points include:
- Where you work
- Where you sleep
- What you use to get around more so, if you have a long commute
- Your favorite reading spot in your home or coffee shop
If you find unusually high readings that could pose a health risk with continued exposure, it might be time to change things up a bit.
4. Wireless Devices
When measuring the EMF radiation coming from wireless devices, you’re ideally looking at the level of radio-frequency radiation emitted. Wireless devices include anything that supports Wi-Fi, Bluetooth, 4G, and 5G. So, your smartphone, PC, tablet, iPad, smart-refrigerator, home security system, smart meter, etc. all fall within that category.
To measure RF radiation, configure your EMF meter settings to “RF.” Next, place the device whose readings you want to take on the floor, on a table or hold it in one hand if it’s small enough.
Point your meter at the device from at least 1 or 2 feet away and slowly move it closer. Keep an eye on the readings as you do this. Take note of the peak RF radiation readings and write them down in your notebook.
They will usually be in milliWatts per square meter (mW/m2). Peak readings matter since information transmitted through wireless networks occurs via packets of data sent over radio waves. So, unlike the steady emission of radiation from magnetic and electric fields, radio waves generate varying pulses of radiation.
If you don’t wait long enough for at least one packet of data to transfer, you might be fooled into believing that the devices in question are radiation-free.
Factors to Consider When Measuring EMF Radiation
Measuring radiation is not a one-size-fits-all affair. Higher EMF readings may not always be cause for alarm. Here are some factors you need to consider when doing a sweep of your building.
1. Seasonal Radiation
As stated before, the adverse effects of radiation become apparent over long periods of sustained exposure. Seasonal radiation isn’t a problem, per se.
There may be periods when the level of radiation might increase due to underlying factors. For instance, consider the ambient EMF radiation emitted from a power line. Levels recorded will be higher during hot summer days when most people have their air conditioning systems turned on.
When summer’s over, there will be a marked reduction in ambient radiation. The same thing is likely to recur during winter when everyone’s drawing an enormous amount of electricity from the grid to power their indoor heating systems.
Likewise, the level of radiation in your home might be higher in the evening than at any other time of day. With all the members of your household home as well as those in the neighboring houses, the amount of electricity being utilized at that time of day will be higher.
So, any readings you take at that time may not be an accurate representation of the true level of radiation that increases your health risk.
2. Emission of Multiple Types of EMF Radiation
Many household appliances emit more than one type of EMF. For instance, if you have an induction cooktop in your kitchen (Know about the radiation of a induction cooktop) or a hairdryer (Check our list of best low EMF hair dryers), there’s a good chance that they will be generating both magnetic-field as well as electric-field radiation.
If you’re working on your laptop while it’s connected to Wi-Fi, there’s a strong likelihood that it is emitting copious amounts of radio-frequency radiation, magnetic field radiation, and electric field radiation.
So, it’s important to configure your EMF meter to different settings to get a clear picture of the levels of the various kinds of radiation different devices are emitting.
3. Cheap EMF Meters Are a Scam
If you go on Amazon or any other marketplace, you’ll be confronted with a large array of EMF meters to choose from. It is in your (and your wallet’s!) best interest to stay away from the cheap ones. Most of them won’t read any level of radio-frequency.
While they typically only pick up magnetic and electric fields, they likely won’t do it accurately either. It might be tempting to go for the cheaper brands, but it’s not worth it in the end if you can’t get reliable readings.
What Constitutes a High EMF Meter Reading
Now that you understand the units for measuring EMF radiation as well as how to get the actual readings, you’re likely now wondering, “What is a high EMF meter reading?”
This final section explores the answer to this question in depth.
High Magnetic Field Readings
Most safety guidelines surrounding magnetic fields base their regulations on the IEEE or ICNIRP standards. The latter generally has stricter guidelines, so their recommended maximum exposure limits are usually lower.
With that said, the ICNIRP guidelines set the maximum magnetic field exposure limit at 2000mG. However, that number is ridiculously high. Here’s why.
If you have a quality EMF radiation meter, you’ll notice that the magnetic field readings in your general surroundings hover somewhere between 0.1mG and 1mG. That’s considered normal for any household.
These numbers will likely be higher if you live in an apartment complex. So, exposure to a whopping 2000mG of magnetic radiation will certainly cause biological harm to your body.
High Electric Field Readings
Electric field radiation is a lot less talked about than its magnetic field counterpart. For this reason, there isn’t as much information out there about what constitutes high electric field readings. The ICNIRP recommends that up to 5000V/m exposure is fine.
However, based on the findings of various studies on the subject, ambient electric field meter readings higher than 10V/m are dangerous. Electronic devices in your home should emit electric fields measuring between 1 and 5 V/m.
High Radio-Frequency Readings
High radio-frequency radiation is the most pervasive and damaging form of EMF in the bunch. When measuring RF, the number that should interest you is the peak number and not the primary one.
According to recent findings of the Bioinitiative report, people who were living around five cell towers that were emitting radiation levels ranging from 0.003 to 0.05 μW/cm2 reported headaches, concentration difficulties, and sleep disturbances. This is equivalent to 0.03 and 0.5 mW/m2 respectively. This is up to 10,000 times less than the recommended regulatory limits. Therefore, 1 mW/m2 constitutes a high RF reading.
Knowledge Is Power
When all is said and done, taking charge of the levels of EMF radiation you expose yourself to is what will ultimately save your life. Identify the sources of dangerous levels of EMF and take practical steps to reduce your overall exposure. Arm yourself with the knowledge gained in this guide to living a healthy exposure-free life. Are Fitbits safe? Check out our blog to read about their long term effects.
Genuis SJ. Fielding a current idea: exploring the public health impact of electromagnetic radiation. Public Health (2007),
Biological effects of power frequency electric and magnetic fields. IEEE Eng Med Biol Mag. 1989;8(3):46-7.