Ghost hunters use a variety of tools and techniques to investigate alleged paranormal activity. While there is no universal acceptance among ghost hunters of the following methodologies, a number of these are commonly utilized by ghost hunting groups.

• Still and video photography - using infrared, digital, night vision, and even disposable film cameras to capture evidence of possible visual manifestations, such as orbs, mist, apparitions, and ectoplasm.

• EMF measurement - using electromagnetic field meters to detect possible unexplained magnetic fields which some attribute to the presence of ghosts and spirits.

• Temperature measurement - using infrared, and thermal cameras, imaging video cameras, and/or hand-held infrared surface and ambient temperature sensors to detect changes in the environment, such as "cold spots", which some believe accompany paranormal activity.

• Digital and analog audio recording - to capture anomalous audio, including voices and sounds that may be interpreted as electronic voice phenomena, which some theorize are attempts at communication by paranormal entities.

• Geiger counter - to measure fluctuations in radiation which some believe will point to a disturbance in spirit energy.

• K2 meter - to "communicate" with an alleged ghost.

• Negative ion detectors - to detect an excess of negative ions which some feel are associated with paranormal activity.

• Infrared and/or ultrasonic motion sensors - to detect possible anomalous movement within a given area, or to assist in creating a controlled environment where any human movement is detected.

• Air quality monitoring equipment - to assess the levels of gases such a carbon monoxide which are thought contribute to reports of paranormal activity. (Also see carbon monoxide poisoning).

• Infrasound monitoring equipment - to assess the level of sound vibrations below 20Hz which is thought to contribute to reports of paranormal activity.

Non-objective "equipment"

• Dowsing rods - usually constructed of brass and bent into an L-shape, dowsing rods may be used by those who feel they help indicate the presence of ghosts and spirits.

• Psychics - trance mediums or "sensitive" individuals thought to have the ability to identify and make contact with spiritual entities. (This practice is considered controversial among groups that prefer a scientific approach)

• Demonologists, Wiccans, Healers - individuals who may say prayers, give blessings, or perform rituals for the purpose of cleansing a location of alleged ghosts, demons, poltergeists, or "negative energy". (Also considered controversial among groups that prefer a scientific approach)

• Interviews - to collect testimony and stories from witnesses, often compiled into a computer database for further study. Some groups also research the history of a location in hopes of learning more about past events and individuals associated with the site.

• Lights-Out Method - Many ghost hunters prefer to conduct their investigations during "peak" evening hours (midnight to 4 a.m.) when most paranormal activity is said to occur. This time period seems to have been put forth in the 1970s and was supported by Lorraine Warren. Most paranormal groups favor the ‘lights out’ or black-out conditions, theorizing that it’s easier to see a possible apparition in the dark since it requires less energy to manifest. According to the theory, spirits/ghosts that attempt to manifest themselves (become corporeal or material-visible) do so by drawing energy from all surrounding sources of both electric and magnetic waves/frequencies. This is one of the reasons why paranormal groups utilize the Gauss (or Electromagnetic Frequency (EMF)) meter. By drawing these energies from surrounding sources, they are enabling themselves to be seen in this plane of existence. A popular thought among ghost hunters is that any equipment that behaves erratically (temporary and inexplicable battery drains, electronic units that shut down, flickering lights or other unexplainable anomalies) point to the presence of a spirit/ghost that is attempting to materialize. Some have even explained that people who experience nausea or dizziness are being subsequently affected by these manifesting spirits/ghosts due to the fact that our brain's synapses (all electrically based) are misfiring and causing an equilibrium change that affects the individual's perception. Additionally, some paranormal investigators point to a disturbance of their equipment by the presence of fluourescent or other types of lighting. Critics of the lights-out method of investigation point to the lack of evidence regarding the apparition-occurrence-to-darkness ratio, indicating that, historically, 80% of full-body apparitions have been witnessed during daylight hours. Daytime investigations, they claim, will produce markedly better results since the video and photographic evidence will be much clearer and more concise for others who scrutinize such evidence. Some also experiment in wavelengths on the fringe of human vision including red and ultraviolet light.