The cost of a lie detector test performed by and analyzed by a certified professional trained in polygraph can be cost-prohibitive, ranging from two hundred to two thousand dollars. The cost depends on the length of the test, the sensitivity of questions asked and the depth of the questions.
There are polygraph machines available to take at home. However, if a lie detector test is not performed by a professional, the results are questionable at best and more for entertainment purposes. Polygraph tests measure a range of physiological changes such as breath rate, pulse rate, blood pressure, skin conductivity and voice stress and has been shown to be 80-98% accurate according to the American Polygraph Association. There are tests based only on voice stress, but the accuracy sharply declines to about 65% accuracy. They are a more affordable option than the standard polygraph test, so you will need to consider if finding out the truth is worth the cost involved.
