The needle jumps, the meter beeps, and someone whispers "did you see that?". It's the signature moment of any investigation — and the one where most mistakes are made. An EMF spike means nothing on its own: it means something when you know how to read it. This guide teaches you exactly that.
The EMF meter is the most used tool in paranormal investigation and, at the same time, the most misread. The difference between a serious investigator and someone who gets spooked by their own fridge isn't the device — it's the method. Let's build that method step by step, with an interactive simulator so you can train your eye before your next session.
The essentials in 20 seconds
- Your meter measures real magnetic fields in microteslas (µT), using the same sensor as your compass.
- Earth already registers 25–65 µT: the absolute number doesn't matter, the deviation does.
- Without a baseline there is no investigation: every spike is judged against that room's normal value.
- An interesting spike is stable, repeatable and sourceless within a one-metre radius.
What your EMF meter actually measures
EMF stands for electromagnetic field. When you use an EMF detector on your phone, the sensor doing the work is the magnetometer: the same chip that drives your compass and helps your GPS. It measures magnetic field strength along three axes and reports it in microteslas (µT).
Here's the first fact that will change how you investigate: the Earth is a giant magnet. Anywhere on the planet, the natural magnetic field already registers between 25 and 65 µT with absolutely nothing going on. If you switch on the meter and see 47 µT, you haven't found a spirit — you've found the planet. That's why absolute numbers mean nothing and comparisons mean everything.
Just as important is knowing what your meter does not measure: the magnetometer is largely insensitive to radio-frequency signals like Wi-Fi or 5G themselves. What it picks up strongly are the magnetic fields of electrical current, motors, transformers and magnets. That nuance explains 90% of false scares.
A real magnetometer
The same sensor as your compass. It measures the magnetic field on three axes, dozens of times per second.
The planet reads 25–65 µT
Earth's field already fills the scale. A "high" resting reading may simply be your city.
The baseline rules
Every room has its normal value. A spike only exists if it breaks away from that local reference.
All on your device
In GhostTech, readings are processed locally. Only if you ask to analyze a photo with AI are that image and its associated readings sent to the cloud.
The baseline: the step that separates the serious
Before turning off the lights and asking your first question into the dark, spend two or three minutes on the most valuable part of the whole session: walking the room slowly with the meter active and memorising (better: writing down) the typical value of each zone.
- Walk slowly and keep the phone steady. Swinging it around already disturbs the axis readings.
- Note the value of each zone: centre of the room, corners, along the walls.
- Locate the obvious sources: outlets, power strips, appliances, the breaker panel, the router.
- Write down the time. The heater or boiler that kicks in at midnight will show up in your data too.
With that you have your baseline: the room's normal electrocardiogram. From now on, the question is never "what does it read?" but "how far is it from what this room always reads?".
Train your eye: the readings simulator
Try the four most common situations of a real investigation. Watch how the reading behaves in each one — the shape of the movement says more than the number.
Field stable
This is a room at rest: Earth's field plus the electrical installation. Your baseline.
The false positives that fool the most people
Almost every "EMF encounter" circulating online has one of these culprits. Learn them and your data will be worth twice as much:
- Motors and compressors: fridges, air conditioners and water pumps generate strong, intermittent spikes. A fridge compressor kicks in on its own, unannounced, in the middle of your session.
- Transformers and chargers: any plugged-in power supply creates an intense field within a few centimetres.
- Wiring inside the wall: a high, constant reading that follows a straight line is usually a hidden cable, not a spectral corridor.
- Everyday magnets: phone cases with magnetic clasps, speakers, car mounts. A magnetic case ruins the entire session — take it off before investigating.
- Your own movement: turning the phone quickly changes the axis readings. Sweeps should be slow and smooth.
The one-metre rule: when you see a spike, look for a source within a one-metre radius before logging it as an anomaly. If there is one, label it and move on. If there isn't — now you have a data point.
When a spike deserves your attention
After ruling out the normal, this is what turns a reading into something worthy of your notebook:
- It's stable: it holds for several seconds — not a tenth-of-a-second flicker.
- It's repeatable: it comes back at the same spot or follows a pattern (for example, when you ask a question).
- It has no source: you've applied the one-metre rule and there's nothing electrical or magnetic nearby.
- It lines up with other tools: an EMF spike in the same minute as a sound on your EVP recording or a figure on the SLS camera is worth a thousand isolated readings.
- It's documented: exact time, exact place, conditions. Without timestamps there is no correlation.
Notice that none of these criteria require believing anything: they're simply good method. And good method is what makes your log stand up the day something genuinely unexplainable shows up.
Put your baseline to the test tonight
GhostTech's EMF radar reads your phone's real magnetometer and combines it with EVP recording, an SLS camera, night vision and surveillance mode in a single free app. Sensor detection is processed on your device.
Frequently asked questions about EMF readings
What unit does an EMF meter use and what values are normal?
Most phone-based EMF meters measure in microteslas (µT). Earth's natural magnetic field already registers between 25 and 65 µT depending on where you are on the planet, so a resting reading of 40-50 µT is completely normal. What matters is never the absolute number — it's how far a reading deviates from that specific room's baseline.
Can a phone magnetometer detect ghosts?
The magnetometer measures real magnetic fields — it's the same sensor your compass uses. No tool, professional or phone-based, can scientifically claim to detect spirits. What you can do is record genuine magnetic anomalies, rule out their normal causes, and treat whatever remains as data to investigate, never as proof.
Why does my EMF meter spike near the fridge or TV?
Motors, compressors, transformers and power supplies generate intense magnetic fields at close range. A fridge can push the reading far above baseline from less than a metre away. It's the most common false positive — which is why the rule is to look for a source within a one-metre radius before getting excited.
What is an EMF baseline and how do you take one?
The baseline is the normal value of each zone of a room before you start investigating. You take it by walking the space slowly for 2-3 minutes with the meter active, noting the typical value of each area and where the obvious sources are (outlets, appliances, the breaker panel). Every later spike is judged against that reference.
What free EMF detector app can I use on Android?
GhostTech includes a free EMF radar that reads your phone's real magnetometer, alongside EVP recording, an SLS camera, night vision and surveillance mode. Sensor readings are processed on your device; only the optional AI photo analysis uses the cloud.
Conclusion
An EMF meter is not a ghost-detecting machine: it's a magnetic-field-detecting machine, which is far more useful. Once you know Earth's field, build your baseline and apply the one-metre rule, 90% of the scares disappear — and the remaining 10% becomes data you can actually work with. If you're starting out, pair this guide with our complete phone ghost-hunting guide and go practise: your own home's baseline is the best training ground there is.
Remember: these tools are for entertainment and technical experimentation. An EMF spike is a real physical data point, but not scientific proof of paranormal activity. Always investigate with respect, safety and a critical mind.