What a Private Investigator Costs in Missouri, and What Moves the Price
Revised September 1, 2026
How much is a PI for a day?
Most day rates are built from an hourly figure rather than a separate price list. Licensed investigators commonly charge about $50 to $200 an hour, with many cases landing between $75 and $150, so an eight-hour surveillance day sits in the high hundreds before mileage and expenses.
Keep reading ↓Imagine it is a Wednesday in Kirkwood and you have been sitting on the same question for three weeks. Something in the story does not line up. You have checked the things you know how to check, twice, and checking them a third time has not helped.
Imagine the same week somewhere else in the metro. A landlord in Ferguson who needs to know who is actually living in a unit. A hearing coming up in St. Charles and a question about where a child spends Tuesday nights. An insurance claim in Maryland Heights that nobody quite believes. A small shop in Affton losing inventory that never shows up on camera.
Different problems, same moment. You have gone as far as you can on your own, and the next step costs money. So before you make the call, it helps to know roughly what the call costs, what the quote is actually made of, and which parts of it you control.
What does a private investigator actually charge?
Nationally, licensed private investigators commonly charge about $50 to $200 an hour, and a large share of everyday cases settle into the $75 to $150 range, according to Bark’s breakdown of private investigator cost. The spread is wide for a reason. It has to cover a two-hour records check and a week of overnight surveillance in the same sentence.
Hourly is the base unit for almost all of this work. Even when you are handed a flat fee or a day rate, somebody built that number out of hours, and those hours came from an assumption about how long the job will take. When the assumption is wrong, the price moves. That is the single most useful thing to understand before you talk to anyone.
Ask what sits on top of the rate. Mileage, database and records fees, court filing costs and the time spent writing your report are commonly billed as separate lines, and a quote covering only field hours is not a quote for the whole job. None of that is a trick. It is the ordinary difference between a rate and a bill.
One thing this page will not do is hand you a St. Louis figure. Local rates are set by individual investigators, they move with the case in front of them, and any article that quotes you a precise metro number is inventing it. What travels across state lines is the national range and the mechanics underneath it.
How much is a PI for a day?
Surveillance is the part of this business most often quoted as a day rate rather than an hourly one, and the day rate is still built from hours underneath. Work from the common $75 to $150 band and an eight-hour day lands in the high hundreds, running toward four figures once mileage and expenses go on. Do that arithmetic before you call so the quote is not a shock.
Then ask what a day means to them. Eight hours, ten and twelve are all used by somebody, and the gap between them is a third of your bill. Ask when the clock starts, too. Travel to the address, time spent waiting on a subject who has not moved, and the hour spent writing up what happened are all real work, and all of it is usually billable.
The day rate does have one genuine advantage for you. It is predictable. You know what a Tuesday costs, which makes it far easier to decide how many Tuesdays you are willing to buy. That decision, more than the rate itself, is what controls your total.
Here is the part people underestimate. Surveillance is not billed by the amount of evidence collected. It is billed by the amount of time somebody sat there watching. A quiet day where the subject never left the house costs exactly what the day that answers your question costs.
Is a retainer the same as your total?
No, and this is where most of the sticker shock happens. Retainers are standard in this field, and a retainer is money held against work that has not been done yet. The final total still depends on how many hours the case genuinely needs, how much travel is involved, and how long a subject stays under observation.
Treat the retainer as an opening balance. When it runs down, the investigator comes back to you for more, and at that point you are making a second decision with better information than you had for the first one. That is not a bad system. It only goes wrong when nobody told you it worked that way.
Get four things in writing before money changes hands: what the retainer buys in hours, what happens to any unused portion, whether the work stops automatically when the balance hits zero, and what the ceiling is if you set one. A written cap is the simplest protection available, and asking for one is completely ordinary. Anybody who bristles at the question has told you something useful.
What actually drives the number?
Four things, mostly: the type of case, where the work happens, the investigator’s experience, and how many hours the job honestly requires. Consumer pricing guides and a working investigator’s own published cost breakdown keep landing on that same short list. Everything else is detail hanging off those four.
The type of case
A background or asset check is desk work: databases, public records, courthouse files, phone calls. An infidelity or custody matter is field work on somebody else’s unpredictable schedule. Corporate and insurance cases often carry heavier documentation standards because the report has to survive scrutiny later. Two cases can share an identical hourly rate and differ tenfold on the invoice, purely because one needs six hours and the other needs sixty.
How many hours the work genuinely needs
The honest hour count is set by the subject, not by you. Someone with a fixed routine is cheap to observe, because the pattern shows up fast. Someone who leaves at random times, works nights, or is already alert to being watched is expensive, because the same answer takes more attempts to get.
Where the work happens
Location moves the rate and it moves the expenses separately. Distance between the investigator and the address gets billed as travel or mileage, and a case that follows somebody from one end of the metro to the other is a longer day than one that stays on a single street. Dense areas, gated properties and long rural driveways each change how the work has to be done.
The investigator’s experience
Experience usually costs more per hour and often less per case. Someone who has run your type of case a hundred times knows which two hours matter and stops burning the other six. The cheapest hourly rate is not automatically the cheapest case, and that is worth holding onto while you compare quotes.
Is it worth it to hire a private investigator?
It depends on what a verified answer is worth to you, and that is a real question rather than a dodge. Here is the test that works: if the answer changes a decision you have to make anyway, a filing, a custody position, a claim, a hire, then paid hours usually cost less than guessing wrong. If the answer changes nothing, you are buying certainty, and certainty is allowed to be worth money too.
Compare against what you would otherwise spend. Chasing the same information through an attorney’s billable hours is rarely the cheaper route, because a lawyer’s time is not priced for sitting in a car. Compare it against the cost of the decision as well. A few hundred dollars of observation is a different scale of number from a case built on an assumption that turns out to be false.
The alternative most people try first is doing it themselves. That is where this gets expensive in ways that are not money. Following someone yourself is unsafe, it can escalate a situation that was stable, and what you gather can be worth less than the same material documented properly by a licensed professional who can explain how it was obtained.
If this is heading for a courtroom, line up the order of operations before you spend. An investigator gathers, a lawyer decides what is useful, and doing that in reverse wastes hours you paid for. Our guide to finding the right lawyer in St. Louis is worth reading first if you do not have one yet.
And if the question is about a job rather than a person, check the ground rules before you pay for anything. Employment situations have their own process, and our rundown on what your rights actually are after being fired in Missouri covers that ground first.
Some of what you want may already be public. Start with Missouri court records.
How long does a PI investigation take?
Days for records work, weeks for surveillance, and nobody can give you a firm end date until they know the subject’s pattern. A background or asset check is largely database and courthouse work, so it moves at the speed of the records. Surveillance runs on somebody else’s schedule, which is exactly why it is billed by time rather than by result.
Set a review point instead of an end date. Agree on a block of hours or a number of days, then stop and look at what came back before authorizing more. You get two things from that: a cost you chose in advance, and a moment where somebody has to tell you honestly whether the case is going anywhere.
A short case is not a failed one. Sometimes two sessions settle the question. Sometimes the honest report is that the pattern you suspected does not exist, and that answer is worth paying for as well, even though it never feels like it on the day.
Is it illegal to hire a private investigator?
Hiring one is legal and ordinary. What is regulated is the investigator. Private investigation is licensed at the state level, and the rules on who may hold a license, and what that license permits, vary from state to state. Everything on this page is general information rather than legal advice, so confirm the current requirements with the state and with a lawyer before you rely on any of it.
Before you hire anybody, ask for their license and confirm it is current in the state where the work will be done. A professional hands that over without any friction at all. Hesitation at that one question is the most useful red flag you will ever get for free.
There are limits on what any investigator can do for you, and those limits protect you as much as anyone. A licensed investigator works inside the law. In practice that means no private phone or message content without lawful authority, no pretending to be law enforcement or a utility, no trespassing, and no access to accounts that are not yours.
So treat a promise as a warning. Anyone advertising that they can pull somebody’s call logs or read their texts for a fee is either overselling what they can lawfully do or planning something that can land back on you, since you are the person who hired them. The good ones tell you what they cannot do in the first conversation.
What should you ask before you sign anything?
Most bad outcomes in this field come from a vague scope rather than a high rate. Ten minutes of questions on the first call fixes more than any amount of comparison shopping. Take this list with you:
- Are you licensed in the state where the work will happen, and can I see it?
- Is this billed hourly or as a day rate, and how many hours is a day?
- What is billed on top: mileage, database fees, report writing, court time?
- How much is the retainer, what does it buy in hours, and what happens to whatever is left?
- Does the work stop when the retainer runs out, or does the bill keep running?
- What do I actually receive at the end: a written report, photographs, video, timestamps?
- Will you testify if this ends up in front of a judge, and is that billed differently?
- What would make you tell me to stop spending money on this?
That last one tells you the most. An investigator willing to say “this is not worth your money” out loud, before taking any of it, is the one worth hiring.
Where do you find private investigators near you?
Get more than one quote before you commit to a retainer. You can browse private investigation services across the metro on St Louis Near Me Directory, then ask each one the same questions and compare what is actually included. Confirm the license is current before any money moves.
Frequently asked questions
Is it worth it to hire a private investigator?
It comes down to whether the answer changes something you have to decide anyway. With hourly rates commonly running $50 to $200, a short block of professional hours often costs less than building a legal position, a claim or a hiring decision on an assumption that turns out to be wrong. If nothing hangs on the answer, you are paying for certainty instead, which is a legitimate reason as long as you know that is the purchase.
Is it illegal to hire a private investigator?
Hiring one is legal and common. The licensing sits with the investigator, and it is regulated at state level, so the requirements differ depending on where the work happens. Ask to see a current license for that state before you hire, and expect a professional to produce it without any fuss. This is general information rather than legal advice, so check anything that matters to your situation with the state and with a lawyer.
Can a PI get phone records?
Not the way people usually mean. A licensed investigator works within the law, and private call or message content is generally reachable only through lawful authority such as a subpoena or a court order, obtained through legal process rather than bought. Some limited information about a number can be researched through public and commercial sources. Anyone advertising that they will pull someone’s phone records for a fee is a red flag, and this is general information, not legal advice.
Can a private investigator read your text messages?
No, not lawfully, and that is worth being blunt about. Message content sits behind accounts and devices that a licensed investigator has no lawful right to enter, and accessing them without authority can create legal exposure for the person who paid as well as the person who did it. If somebody offers you that service, walk. In a legal case, message evidence normally comes through the court process instead, which is a question for your attorney.
Can you sue someone for hiring a PI on you?
Hiring a licensed investigator to make lawful observations in public places is generally not, by itself, the thing people end up suing over. Claims tend to arise from conduct instead: harassment, trespassing, or unlawful access to private information. Whether any of that applies to your situation depends on the specific facts and on state law, so it is a question for a lawyer rather than an article. Nothing here is legal advice.
How to tell if a PI is watching you?
Competent surveillance is designed to be unremarkable, so most people never notice it. What people do report is the same unfamiliar vehicle parked nearby on different days, or hearing that someone has been asking neighbors, coworkers or a landlord questions about them. Two things are worth separating here. Lawful observation from a public place is one situation. Feeling followed or unsafe is a different one, and that belongs with the police rather than with guesswork.
How long does a PI investigation take?
Records and background work can move in a few days because it depends mostly on how fast databases and courthouses respond. Surveillance is open-ended by nature, since it runs on the subject’s schedule rather than yours, and that is exactly why it is billed by time. The practical move is to buy a defined block of hours, review what came back, and decide again from there rather than authorizing an investigation with no end point.
Do private investigators charge for travel time?
Usually yes, in one form or another, and it is one of the biggest reasons two quotes for the same job come back different. Travel may appear as billable hours, as mileage, as a separate expense line, or be folded into a day rate. Distance between the investigator and the address matters, and so does how far a subject moves during the day. Ask specifically how travel is handled before you agree to anything.
More St. Louis guides
- How to find your court date and records in Missouri
- How to find the right lawyer in St. Louis
- Fired in Missouri: what your rights actually are
Written by a dedicated team of St. Louis locals who live, work, and play right here in the St. Louis metro. Founder Lane Forman and team are committed to building the region’s most trusted directory by verifying listings and connecting local businesses with loyal customers across Missouri and Illinois.