How much does a lie detector test cost?
Ashburn, VA

How much does a lie detector test cost?

Ashburn, VA

How much does a lie detector test cost?

$400 – $1,200 average cost

Get free estimates for your project or view our cost guide below:

$400 – $1,200 average cost


Get free estimates for your project or view our cost guide below:
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Tara Farmer
Written by
Tara Farmer
Edited by
Tamatha Hazen
Fact-checked by
Kristen Cramer

Average polygraph test cost

A lie detector test costs $400 to $1,200 on average, but prices can range from $200 to $2,000+, depending on the location, examiner experience, test type, and services included. Basic screening polygraph tests take 1 to 2 hours and cost less than those involving multiple or complex issues or topics.

Average lie detector test price
National Average Cost $800
Minimum Cost $200
Maximum Cost $2,000+
Average Range $400 to $1,200

  • Polygraph tests are commonly used in law enforcement, government, and the corporate world to indicate deception, but they cannot 100% prove someone is lying. Both the National Academy of Sciences and the Journal of Law and Human Behavior have highlighted the scientific limitations of these tests.

  • The Employee Polygraph Protection Act restricts most private employers from using polygraph testing for pre-employment screening or requiring existing employees to take such a test. The Act also gives strict guidelines for testing when it is allowed.

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What is a polygraph test?

A polygraph test, commonly called a lie detector test, is a procedure that measures and records physiological indicators while asking the subject questions. The data is then analyzed to determine truthfulness or deception. Polygraph testing is based on the theory that lying causes subtle but detectable and measurable physiological changes.

How does a lie detector test work?

A lie detector test typically takes place in a room with just the subject and the examiner. During an initial pre-test interview, the examiner conducts a medical and mental health screening. After explaining the details of the procedure, the examiner begins setup and testing:

  1. The polygraph examiner applies sensors to measure factors such as the subject's blood pressure, breathing and heart rate, pulse, and perspiration.

  2. The examiner asks a series of control questions unrelated to the topic—typically simple questions like your name and address—to establish baseline physiological measurements.

  3. Then, the questions continue, with a mixture of more control questions and questions related to the issue.

  4. After the test, the polygraph examiner analyzes the data to determine if the subject is being truthful or deceptive in their responses.

Lie detector test cost factors

Polygraph test prices can vary significantly depending on several key factors:

  • Location: Like most services, major metro areas tend to have higher polygraph test prices, sometimes up to 25% more compared to rural areas.

  • Experience level: An examiner’s training, credentials, experience, and professional reputation can influence costs. Examiners with extensive backgrounds often charge higher rates.

  • Test length / number of questions: Some tests take longer than others, which affects the cost. Screening tests are shorter than specific-issue tests, which examine a particular situation in depth. Full-scope or multi-issue polygraphs are the most time consuming.

  • Test purpose: Polygraphs performed for pre-employment screening for sensitive jobs like those involving national security, or other high stakes matters like a crime investigation tend to cost more than tests for personal reasons.

  • Number of tests: Some situations involve multiple tests, such as a case of infidelity where both parties are accusing each other. Some providers offer a discounted rate when purchasing multiple tests, but the total cost will be higher than for a single test.

  • Travel: If the examiner must travel to a remote location to conduct testing, they may add on travel fees. Mileage and lodging expenses increase costs.

  • Additional services: Many examiners offer add-on services like test result analysis, detailed reporting, court testimony, and legal consultation for extra fees.

A man taking a polygraph lie detector test.
A man taking a polygraph lie detector test.

FAQs about lie detector tests

How accurate are lie detector tests?

Opinions on lie detector test accuracy vary widely. Some studies show accuracy of over 90% while critics argue for accuracy closer to 75%. In general, polygraph testing is considered most accurate when proper protocols are followed and conducted by a highly trained, experienced examiner in a controlled setting.

The debate over polygraph reliability stems from several issues:

  • Many factors besides deception can affect physiological measurements, including stress, anxiety, medications, and medical conditions. This may skew test results.

  • Quality of training and analysis varies between examiners which impacts accuracy.

  • Test formats and questioning techniques can significantly impact results.

  • Though polygraphs are resistant to most countermeasures, some can artificially skew outcomes if done correctly.

Are lie detector tests admissible in court?

The admissibility of lie detector test results as evidence in court varies from state to state and is determined by each trial judge. Many states allow admission of polygraph testing if both parties consent in advance. However, some states prohibit polygraph evidence entirely while others have no clear precedent.

Where can I take a lie detector test?

Polygraph tests are widely available from government agencies, private examiners, and online vendors. Law enforcement agencies may conduct testing during criminal investigations. Many private examiners market polygraph services to the public and private sector. Many companies now provide mobile polygraph testing options.

A good place to begin your search is with the American Polygraph Association or the American Association of Police Polygraphists membership directories.

Can you beat a lie detector test?

Techniques people use in an attempt to “beat” a polygraph are generally ineffective when an experienced examiner follows proper testing protocols. Attempting to beat the test often backfires by indicating deception. However, someone trained in complex countermeasures may be able to manipulate test results to some degree in ideal circumstances.

The most reliable way for an honest person to pass a polygraph is to answer all questions truthfully, listen carefully, follow instructions, and avoid countermeasures. Truthful subjects have the best chance of passing.

How long does a polygraph test take?

A basic polygraph test takes 1 to 2 hours on average, but the time can vary significantly depending on the exam's scope. Employment screening lie detector tests typically take 60 to 90 minutes, while testing for a specific issue like a crime can take 90 to 120 minutes, or longer if it involves multiple issues or topics.

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The pre-test interview, medical baseline readings, and post-test analysis also lengthen the process. Allow at least 2 to 3 hours for the complete polygraph testing process.

What to look for in a lie detector test provider

Properly vetting the polygraph exam provider helps avoid frustration and ensures the most accurate, reliable test experience. Here are guidelines to follow when evaluating lie detector test providers near you:

  • Look for an examiner with accredited polygraph training from a reputable institution along with continuing education.

  • Confirm the examiner is licensed in your state (if applicable) and belongs to a professional polygraph association like the American Polygraph Association (APA). Verify their credentials and look for past ethics violations.

  • Choose a professional who's been a licensed polygraph examiner for 5 to 10+ years, has conducted at least 500 exams, and specializes in the type of test you need for the most reliable results.

  • Check out polygraph examiner reviews and complaints on sites like Lawful and Google.

  • Ask about their testing approach to ensure it's consistent with best practices for accuracy.

  • Confirm all costs and procedures in writing before paying for the test or signing any documentation.

Questions to ask a polygraph test provider

Ask these questions to feel confident you’re choosing a competent, ethical polygraph examiner who will deliver accurate, reliable test results.

  • How long have you worked as a polygraph examiner? How many tests have you conducted?

  • What professional certifications and/or licensing do you have?

  • Where did you complete your polygraph examiner coursework?

  • Are you a member of the American Polygraph Association or any other professional organization?

  • Do you have experience with my type of test (such as pre-employment or infidelity)?

  • How long does this type of polygraph test typically take?

  • What method or technique will you use for my specific test purpose?

  • What is your accuracy rate? How often do you have inconclusive outcomes?

  • What protocols are in place in your testing environment to maximize accuracy?

  • Will you provide a detailed written report of test questions, responses, measurements, analysis, and conclusion?

  • How long does it take to get the test results?

  • What are your fees for my specific test? Do you charge a flat fee or hourly?

  • Are there any discounts available on your polygraph tests?

  • What is your availability for scheduling a testing appointment?

  • What is your cancellation policy?