Whether a contractor charges sales tax to customers depends on what kind of work is being done. For a capital improvement to real property, most states treat the contractor as the final consumer of the materials: you pay sales tax at the supply house and the customer sees no sales tax on the invoice. For a repair, the state treats you as a retailer: you buy materials tax-free with a resale certificate and collect sales tax from the customer on the materials portion of the bill. Same box of shingles, different tax treatment, depending on the job it goes into.
Capital Improvement or Repair
State tax codes draw a hard line between two categories of work, and that line decides who owes the tax.
A capital improvement adds something new to real property or substantially extends its useful life. Building a deck, installing a new HVAC system, adding a room, and replacing an entire roof all sit on this side. A repair restores property to its previous condition without meaningfully increasing value or lifespan. Swapping a broken window pane, patching a few shingles, and fixing a leaking faucet are repairs.
The same material can flip categories depending on the job. A box of shingles for a full roof replacement is a capital improvement purchase. That same box used to patch a ten-square-foot section is a repair purchase. Installing a brand-new built-in mailbox into a brick column is a capital improvement, and the customer sees no tax. Bolting a replacement mailbox onto an existing post is a repair, and you collect tax from the customer on the mailbox.
Many states use a “true object” test for borderline transactions. The test asks what the customer is actually paying for. If the customer’s primary goal is a physical product and labor is incidental, the transaction leans toward a taxable sale of materials. If the customer is paying for expertise and materials are a minor component, it leans toward a non-taxable service. Some states apply a specific percentage threshold: if material cost falls below a set share of the total contract price, the entire transaction may be treated as a service.
When You Charge the Customer, When You Pay at the Supplier
Capital Improvements
On a capital improvement, you pay sales tax on materials when you buy them from your supplier. Your invoice to the customer includes your price for materials and labor with no separate sales tax line. From the state’s perspective, the tax was already collected at the supply house and the transaction is complete. The materials stopped being tangible personal property the moment they became part of the real estate.
The practical implication for bidding: the sales tax on materials is your cost, and it has to be built into your bid. Contractors who forget this effectively hand customers a discount equal to the tax rate on every material dollar.
Repairs
On a repair, you act as a retailer. You buy materials tax-free using a resale certificate, then charge the customer sales tax on the materials portion of the final invoice. This is the scenario where the answer to “does the contractor charge sales tax” is yes.
Using a resale certificate only works when you genuinely intend to resell the materials as part of a taxable transaction. Issuing one to buy materials you’ll consume in a capital improvement is one of the fastest ways to trigger an audit, and you’ll owe use tax on the full cost with penalties and interest added.
Separated vs. Lump-Sum Contracts
How you write the contract shapes how tax flows through the job. A time-and-materials or separated contract lists materials and labor as distinct line items. For repairs, this structure is what allows you to buy materials tax-free and then collect tax only on the materials line. In some states, even for capital improvements, a separated contract shifts the collection point: instead of paying tax to your supplier, you collect it from the customer on the marked-up material price.
A lump-sum contract gives the customer one number. For capital improvements this is straightforward, since you paid tax at the supply house and the invoice shows a single price with no tax line. The risk is using a resale certificate to buy materials for a lump-sum capital improvement job: you’ll owe use tax on those materials because you consumed them rather than reselling them, and some states audit aggressively for that pattern.
Labor Charges on the Invoice
Labor is non-taxable in most states, provided you separately itemize materials and labor on the customer’s invoice. Lumping everything together can cause the entire charge to become taxable, which is an expensive mistake on a labor-heavy repair job.
A handful of states tax construction labor. Some impose their tax on the entire contract price, including both materials and labor, through mechanisms like gross receipts taxes or transaction privilege taxes rather than a traditional sales tax. Others tax labor only for certain types of work, such as services to existing commercial property, while exempting labor on new construction or residential remodeling. At least one state applies a separate contractor’s excise tax instead of the standard sales tax. Assuming labor is always exempt will eventually cost you money in the wrong state.
Five states impose no statewide sales tax: Alaska, Delaware, Montana, New Hampshire, and Oregon. Alaska permits local jurisdictions to levy their own sales taxes, so contractors working in certain Alaska municipalities may still have collection obligations.
Mixed Jobs
Real projects rarely fall neatly into one category. A kitchen renovation might include new cabinets permanently installed (capital improvement) alongside a replacement garbage disposal (repair). A bathroom remodel could involve new tile installation next to fixing a leaky pipe.
The general expectation is that you break the project into its component parts and apply the correct tax treatment to each. Capital improvement materials get taxed at the supply house. Repair materials get resold to the customer with tax collected. Your invoicing has to be detailed enough to separate the two, and your purchasing records need to track which materials went to which portion of the job. Treating the whole project as one category for convenience is a gamble that auditors are trained to catch.
When the Customer Is Tax-Exempt
Some customers are exempt from sales tax entirely. Government agencies and qualifying nonprofit organizations are the most common examples. When working for an exempt client, the client provides an exemption certificate that allows you to purchase materials tax-free and skip collecting tax on the invoice.
The exemption belongs to the client, not to you. You’re responsible for obtaining and retaining the certificate, and if an auditor asks for it and you can’t produce it, you owe the tax the client should have been exempt from. Not every state handles these exemptions the same way. In some, the certificate lets the contractor buy materials tax-free directly. In others, the exemption only applies to certain organizations or certain types of work. Get the certificate before you start buying materials, not after the job is done.
Some states also use capital improvement certificates, where the property owner signs a form confirming that the work qualifies as a capital improvement before the contractor treats it that way for tax purposes. If the customer signs and the work turns out not to qualify, the customer, rather than the contractor, may be liable for the unpaid tax. Where these certificates exist, they are worth the paperwork.
Working Across State Lines
Contractors who cross state lines to perform work create nexus, a connection to the state that triggers registration and collection obligations. For construction contractors, physical nexus is almost automatic. If you’re on a job site in another state with your employees and your equipment, you have a physical presence, and most states with a sales tax will require you to register, collect, and remit.
Economic nexus is based on revenue rather than physical presence and typically sits at $100,000 in annual sales within a state, though a few states set the bar at $250,000 or $500,000. Some states also count transactions, commonly triggering obligations at 200 or more sales per year. For contractors, physical nexus almost always arrives first. A crew and a truck on the site establish presence on day one.
Use tax picks up what sales tax missed. If you buy materials from an out-of-state supplier who didn’t charge your state’s sales tax, or if you pull inventory from your own stock for a capital improvement, you owe use tax to the state where the materials are used. The rate is almost always the same as the sales tax rate. If you already paid sales tax to another state on the same materials, most states give you a credit and you pay only the difference. Keep the receipts, because the credit isn’t automatic.
What Happens If You Get It Wrong
Uncollected sales tax is treated by states as money you owed and didn’t pay, not as an accounting correction. Late filing penalties typically start at around 5% per month of the unpaid balance and can climb to 25% or more. Interest accrues from the original due date, not from when the state catches the error.
The expensive mistake isn’t usually a single bad invoice. It’s a systematic pattern: treating all work as capital improvements and never collecting tax on repairs, or using resale certificates for every purchase regardless of job type. Auditors look for patterns, and when they find one, they extrapolate the error rate across all of your returns within the audit window. Most states can look back three to four years from the filing date, several extend to six, and where the state believes you significantly underreported or never filed, many have no statute of limitations at all. A 5% error rate on one year’s returns can become a six-figure assessment when applied across four years of business.
Registering for a seller’s permit is free in most states, and the compliance cost is almost entirely bookkeeping discipline: itemized invoices, resale certificates on file with each supplier, exemption certificates from tax-exempt clients, and purchase records that tie materials to specific jobs. Compared to the cost of an audit assessment, that discipline pays for itself many times over.