Most of what changes for a tradesperson in Missouri is set by the state, not Washington: how you get paid, whether you need to register, and what you owe in tax. Here is what actually differs, and where to run your own numbers.
Each section below points to a tool that runs your exact numbers for Missouri.
Tax in Missouri
Missouri has a graduated state income tax that runs up to 4.7% at the top, on top of your federal taxes. Graduated means the rate climbs as your profit does, so a good year costs proportionally more. You owe federal income tax and self-employment tax as well, and you make estimated payments to both Missouri and the IRS through the year.
On sales tax, Missouri follows the usual rule for the trades: your labor is not taxed, and you pay sales tax on your materials when you buy them rather than charging it to the customer.
Work out what to hold back on the Tax Set-Aside Calculator, which runs the federal and self-employment numbers for Missouri.
Getting paid: liens and retainage
A mechanic's lien is the tool that actually gets a Missouri contractor paid, and in Missouri you generally have to record it within 6 months of your last day of furnishing. Miss it and you lose the lien, so the dates matter.
Enforcing it has its own clock. 6 months from filing. Work out your dates on the Lien Deadline tool, and if they are close, get an attorney to confirm them against the statute (Mo. Rev. Stat. §§429.080, 429.100, 429.170).
On money held back as retainage, here is where Missouri lands:
NOT VERIFIED AS A WHOLE ROW. Mo. Rev. Stat. §436.303 was read in full and the private 10% trust cap carries its own citation. §34.057 returned a stub from revisor.mo.gov, so the public cap and every release timing on this row are unread.
- Private work: 10% of any payment due from the owner to the contractor.
- Public work: No statutory cap on public work in Missouri. Whatever your contract says governs, so read the withholding clause.
- Release: Not verified on either private or public work.
Heads up: Only the private cap is verified. The public cap and the release timing were not readable from here and must be confirmed.
Check the Retainage Calculator before you sign a contract that holds back more.
There is no Missouri retainage letter on this site, and the NOT VERIFIED line above is why. A letter that tells the party holding your money what to hand over only gets written over a row that has been read against the statute in full. The Document Hub carries the forms that do not turn on a state rule.
Do you need a license in Missouri?
Missouri has no statewide general contractor license, so for most building work there is no state license to get. That is one of the things that makes Missouri straightforward to start in. It does not mean no rules at all: the state still licenses specific trades like electrical and plumbing, and your city or county can require its own registration or permits, so always check locally before you take a job on.
Trade licenses for electrical, plumbing and HVAC are usually separate and often required even where a GC license is not. See what applies to your trade on the Contractor License Checker.
Building codes and permits
Missouri has no single statewide building code, so the edition you build to and whether you need a permit depend on your city or county. Do not assume the town next door adopted the same code or the same amendments.
- Homes: none statewide; adopted city by city, with St Louis on the 2018 IRC and others ranging across 2015 to 2021
- Electrical: none statewide for house wiring; the only state electrical adoption is the NESC, a different code covering utility lines
- Energy: none statewide
- Plumbing: none statewide; plumber certification is required only in cities over 15,000 people
Missouri has no statewide building, electrical, energy or plumbing code for private work, and its own Division of Fire Safety says so. Where a city or county has adopted nothing, no code of that family applies at all and nothing fills the gap. Two things are easy to misread. The state does adopt an electrical code, but it is the National Electrical Safety Code, which covers utility supply and communication lines rather than the wiring in a house. And plumber certification is only required in cities of more than 15,000 people, so outside those there is no licensing regime either. A bill to create a statewide baseline was proposed to take effect on 28 August 2026 and died in committee.
Source: Missouri Division of Fire Safety, Department of Public Safety (dfs.dps.mo.gov); 4 CSR 240-18.010, Public Service Commission (NESC); Chapter 341 RSMo (plumbers); HB 3466 and SB 1431 of the 2026 session, neither enacted. Read against that source on 2026-08-25.
Check a specific job on the permit tool.
Pay and workers' comp
The minimum wage in Missouri is $15.00 an hour. That is the floor for anyone you put on the books, and it is worth confirming against the state labor department each year because several states step their rate mid-year. Check a rate on the minimum-wage tool.
Workers' comp rates in Missouri are not published as a single figure; they turn on your trade's class code and your payroll. Get a realistic range on the Workers' Comp Estimator, then get a real quote.
If a client will not pay
If a client will not pay, you can sue for up to $5,000 in Missouri's Circuit Court, Small Claims Division. That covers most unpaid-invoice disputes for a small outfit; a bigger claim goes to regular civil court where you will probably want an attorney. Walk through whether filing is worth it on the Small Claims checker.
The clock runs the other way too: a client generally has 5 years to sue you over the work under a written contract in Missouri, and there is no absolute cutoff, so your exposure turns on when a defect is found. Work out your exposure on the Warranty & Claim Deadline tool.
Common questions
How much state income tax will I pay in Missouri?
Missouri has a graduated rate up to 4.7% state income tax on your profit, on top of federal income tax and self-employment tax. Use the Tax Set-Aside Calculator to see what to hold back.
Do I need a contractor's license in Missouri?
For most general building work, no. Missouri has no statewide general contractor license. The state still licenses specific trades and your city or county may require its own registration, so check both.
What is the small claims limit in Missouri?
You can sue for up to $5,000 in Missouri's Circuit Court, Small Claims Division. The filing fee is typically $35 to $100. Larger claims go to regular civil court.
How long do I have to file a mechanic's lien in Missouri?
Generally 6 months from your last day of furnishing. Miss it and you lose the lien. Work your own dates out on the Lien Deadline tool.
What is the minimum wage in Missouri?
$15.00 an hour in Missouri, above the federal $7.25. Several states step their rate mid-year, so confirm it before you set a payroll.
What building code does Missouri use?
There is no single statewide building code in Missouri: the edition, and whether you need a permit at all, are set by your city or county. Homes: none statewide; adopted city by city, with St Louis on the 2018 IRC and others ranging across 2015 to 2021. Do not assume the next town over adopted the same thing.
The honest bit
These are the 2026 rules for Missouri as they stood when this guide was written, and they change: legislatures move thresholds, deadlines and rates every year. Treat this as general guidance to point you in the right direction, not legal, tax or financial advice. Verify anything you rely on at the source (the IRS, the Missouri tax and licensing agencies, and your local building department) or with a professional. Where Missouri does something unusual, the detail is called out above rather than glossed over.
Related: Tax Set-Aside Calculator · Mechanic's Lien Deadline · Contractor License Checker · Small Claims checker · Working in Your State
Know someone who needs this?
Keep reading
Templates you might need
Sources
- Missouri Revisor of Statutes - Revised Statutes of Missouri(RSMo) · Mechanics lien notice, filing and enforcement deadlines in Missouri: Mo. Rev. Stat. §§429.080, 429.100, 429.170. Verified against this authority on 2026-08-09.
Was this guide useful?
Didn't find what you were looking for?
Spotted something wrong or out of date? Email us at hello@kilnguides.co.uk.
In crisis? 988 Suicide & Crisis Lifeline 988 ·