Do Contractors Charge Sales Tax? Lump-Sum vs. Time and Materials

On this page 7 sections

1. Do Contractors Charge Sales Tax? It Depends on Your Role
2. Lump-Sum Contract Sales Tax: Tax Paid at the Supply House
3. Time and Materials Sales Tax: Separately Stated on the Invoice
4. Capital Improvement Sales Tax Exemption vs. Repair: Why the Label Matters
5. Using Resale and Exemption Certificates Correctly
6. Setting up Your Invoicing Software to Tax the Right Lines
7. Next Steps

Key takeaways

• Whether you charge sales tax often depends on whether your state treats you as the consumer of materials or as a retailer reselling them.
• On many lump-sum jobs, tax is paid at the supply house and is not added again on the customer invoice.
• Time-and-materials invoices often require tax as a separate line on materials, and sometimes on labor, depending on the state and the type of work.
• Contract type, the capital improvement vs. repair label and certificate use all affect who owes tax. Confirm your state's rules with a tax professional.

Do contractors charge sales tax? Sometimes. The answer usually depends less on your trade and more on how the job is contracted and what kind of work it is. In many states, a contractor on a lump-sum job is treated as the final consumer of materials and pays tax at the supply house. On a time-and-materials job, the tax may belong on the customer's invoice instead. This guide covers the consumer-versus-retailer distinction, how contract type and the capital improvement vs. repair label change the answer, how to use resale and exemption certificates, and how to set up your invoicing so tax lands on the right lines.

Important: Sales tax rules for construction vary a lot from state to state, and sometimes by locality. This article is general information, not tax or legal advice. Before you change how you bill, confirm your obligations with your state's department of revenue and a qualified CPA or tax advisor.

Do Contractors Charge Sales Tax? It Depends on Your Role

Sales tax applies to retail sales, and someone in the chain has to pay it once. For contractors, the key question is whether you are the consumer of the materials you install or a retailer who resells them to the customer.

Contractor as Consumer of Materials

When materials become part of real property, many states treat the contractor as the end user. Framing lumber, drywall, roofing and a water heater that gets plumbed in are typical examples. In those states, contractor sales tax on materials works like this: you pay the tax when you buy the materials, then build that cost into your price, the same way you build in fuel or equipment wear. The customer pays the tax indirectly through your price, not as a separate line.

Contractor as Retailer of Materials

In other situations, the contractor is treated as selling the materials to the customer. Common examples include:

• Your contract or invoice separately states and marks up materials.
• You sell items over the counter without installing them.
• You install items that stay tangible personal property instead of becoming part of the building, such as some freestanding appliances or movable fixtures, depending on the state.

As a retailer, you may be able to buy those materials tax-free with a resale certificate. You then charge tax to the customer and remit it.

Why the Line Moves From State to State

Some states treat contractors mostly as consumers. Others treat them as retailers by default. Many use a mix that turns on contract wording, how the invoice is laid out and the type of work. Some states also tax certain construction or repair labor as a taxable service. That is why a crew working in two states can owe tax in two different ways on identical jobs.

Lump-Sum Contract Sales Tax: Tax Paid at the Supply House

A lump-sum (fixed-price) contract quotes one price for the finished job. Materials and labor are not broken out for the customer. In states that follow the consumer model, the usual pattern looks like this:

1. You pay sales tax on materials when you buy them from the supplier.
2. You include that tax cost in your bid.
3. Your invoice shows the contract price with no separate sales tax line.

The double-tax trap: If you paid tax at the supply house and then also add sales tax to the homeowner's invoice, the customer is taxed twice on the same materials. In some states, tax you collect from a customer must be remitted even if it wasn't owed, so you can't just keep it. Either way, you have an unhappy customer and a messy fix.

Watch for Use Tax on Untaxed Purchases

If you buy materials from an out-of-state or online supplier that doesn't charge your state's tax, you may owe use tax on those purchases. The same is true if you pull from inventory you bought tax-free on a resale certificate and install it on a lump-sum job. Auditors commonly compare purchase records against job files to find these gaps. Keep supplier invoices tied to job numbers so you can show where tax was paid.

Time and Materials Sales Tax: Separately Stated on the Invoice

Time-and-materials (T&M) and cost-plus jobs bill labor hours and itemized materials, often with a markup. Because you are visibly selling materials to the customer, many states treat these lines as retail sales. When that applies:

• You may buy the materials tax-free with a resale certificate, if your state allows it for this job type.
• You charge sales tax on the materials line, usually including your markup, and show it separately on the invoice.
• Labor may or may not be taxable. That depends on whether your state taxes that kind of service and whether the work counts as a repair or a capital improvement.

Illustrative Example

The numbers below are illustrative only and use a made-up 7% rate. They show structure, not your actual tax.

On the lump-sum job, the $280 is your cost. On the T&M job, the $336 belongs to the state, and you are only holding it.

Mixed Contracts and Change Orders

Real jobs blur the lines. A lump-sum contract might include material allowances. A fixed-price remodel might pick up T&M extras midway through. Each piece may need different tax treatment. When you write construction change orders that add materials or labor, state clearly whether the change is priced as a lump sum or itemized. That choice can decide whether tax goes on the change order.

Capital Improvement Sales Tax Exemption vs. Repair: Why the Label Matters

Many states draw a line between a capital improvement, which adds permanent value or extends the life of real property, and a repair or maintenance job, which keeps property in its current condition.

Where a state offers a capital improvement sales tax exemption, it usually covers what the customer is charged. It does not cover what you pay for materials. You may still owe tax at the supply house even when the homeowner pays no tax on your invoice.

The label must match the work. Calling a repair a "capital improvement" to skip tax is exactly what auditors look for. If the job is borderline, such as replacing part of a system or doing a large repair, document the scope in the contract and ask your tax advisor how your state classifies it.

Using Resale and Exemption Certificates Correctly

Certificates move the tax obligation to a different party. That only works if they are used for the right purpose.

Resale certificates let you buy materials tax-free because you will resell them and collect tax from the customer. Use them only for materials you will actually bill as a retail sale, such as T&M materials in a state that treats them that way. Don't use them for materials that go into lump-sum jobs where you are the consumer.

Exemption certificates come from customers who claim an exemption. That might be a qualifying nonprofit, a government entity or a property owner certifying a capital improvement where the state provides for it.

A practical checklist:

• Collect the certificate before you invoice, not after an auditor asks.
• Check that it is complete, signed and the correct form for your state.
• Store it with the job file, along with the contract and invoices.
• Track any expiration dates on repeat customers' certificates.
• Don't accept a certificate you know doesn't fit the job. In many states, good faith protects you only when you had no reason to doubt the certificate.

Setting up Your Invoicing Software to Tax the Right Lines

Software defaults are a common source of tax errors. A single "tax everything" setting can overcharge lump-sum customers and under-collect on T&M jobs. Set it up deliberately:

1. Create separate item types for taxable materials, nontaxable materials (already taxed at purchase), taxable labor and nontaxable labor.
2. Build job templates by contract type. For example, use a lump-sum template with no tax line and a T&M template that taxes materials.
3. Set tax rates by job location, not your office address, if your state sources tax to where the work is done.
4. Flag exempt customers and attach their certificates to the customer record.
5. Reconcile with your books. Regularly compare the sales tax shown on invoices with what you record and remit. If you keep your books in QuickBooks, MannyPay offers a QuickBooks integration for merchants who use it.
6. Review a sample of invoices each quarter against your tax advisor's guidance.

How Payments and Card Fees Interact With Sales Tax

When a customer pays by card, the amount you charge includes any sales tax on the invoice. Contractors often take payments in the office or over the phone, and a virtual terminal for keyed and invoiced payments lets you charge the exact invoice total, tax included. For multi-stage projects, make sure each milestone payment on a construction draw schedule carries the correct share of tax, or none on lump-sum draws.

If you add a card fee, two questions come up: whether the fee is calculated before or after tax, and whether the fee itself is taxable. Both depend on state law and card network rules. Read up on charging a credit card fee on progress invoices before you turn one on, and ask your tax advisor how your state treats it.

Next Steps

To avoid double-taxing customers or absorbing an audit bill, match three things on every job:

• How you bought the materials (taxed or on a resale certificate)
• How the contract is structured (lump-sum or itemized)
• What your invoice shows (a tax line or none)

Start by asking your CPA how your state treats lump-sum, T&M, capital improvement and repair work. Then build invoice templates that reflect those answers.

If you're also reviewing how you accept payments, MannyPay offers payment solutions for in-person, online and keyed transactions, including card terminals, virtual terminals and gateways. You can request a free processing quote, and a MannyPay specialist will respond within one business day.

ME

About the author

MannyPay Editorial Team

Beyond the Swipe's editorial desk researches the publication's guides and news and cites its sources in every article. Articles reviewed by a named MannyPay editor carry that editor's byline.

This article is for general educational purposes and is not legal, tax or financial advice. Card network rules and state laws change; confirm current requirements for your business.