Subcontractor markup: what to charge when you bring in a sub

You're an HVAC tech. A customer wants a full system replacement, but the new layout needs ductwork redesign outside your license. You call in a sheet metal sub you trust—they come in at $1,800. What goes on the customer's estimate?

If you pass $1,800 straight through and charge only for your own labor, you've spent two days coordinating, scheduling, and standing behind someone else's work for nothing. Subcontractor markup is how you recover the coordination time, insurance exposure, and overhead a multi-trade job puts on a one-person operation. This guide walks through what to charge, how to present it on your quote, and the one question that generates endless arguments on contractor forums.

What your subcontractor markup actually has to cover

When your client hired you, they hired you to guarantee the entire job. If the sub you brought in makes a mistake, the customer calls you—not the sub. That liability, plus the real cost of coordinating two schedules, plus your business overhead, plus the self-employment tax you owe on any profit, all run against what looks like a simple markup percentage.

Here's what eats into the gross margin before you actually pocket anything:

• Coordination time. Even a clean sub job takes phone calls, a site visit or two, schedule management, and a final quality check. Two hours at your billable rate is real cost against whatever you make on the markup.
• Insurance exposure. Your general liability policy covers the full scope of your contract—including work a sub performs under your agreement. You pay that premium every year; the markup is where you recover it on the jobs that use a sub.
• Administrative overhead. Scheduling, invoicing, permit tracking, client updates. Your business runs on fixed costs that don't disappear because someone else is holding the wrench.
• Self-employment tax. The IRS charges 15.3% in self-employment tax on net self-employment income. That applies to your markup margin—so a $300 gross markup on a $2,000 sub job yields roughly $254 before any coordination time or overhead comes off the top.
• A risk buffer. If the sub runs a day late or their work needs a callback, that's on you to handle with the customer. A couple of extra percentage points built into the markup buys you room to absorb it.

How much markup to charge on subcontractor work

There's no regulation that sets a floor, but there's math that tells you where the real minimum is.

Start with the self-employment tax: if you mark up a $2,000 sub job by 10% ($200 gross), you keep roughly $169 after SE tax—before any coordination time or overhead. For anything more involved than a quick pass-and-done arrangement, 10% almost certainly leaves you working at a loss once you account for your actual time.

In practice, most solo trade contractors working through this math land here:

15% is a defensible floor for most solo operators on straightforward residential work. It covers your SE tax exposure and one to two hours of coordination at most billable rates; anything above it is net margin.

If you're still working out your base markup rate on materials and labor, how to calculate markup on a contractor quote walks through the core formula step by step. The markup calculator will let you run the exact numbers for any sub scenario.

Do you have to tell your client you're marking up the sub?

For standard residential work under a fixed-price contract: generally no. You're the prime contractor. Your client hired you to deliver a complete result at a price, and how you source labor is your business decision—the same way a plumber doesn't explain the distributor margin on every fitting they install.

Two situations where the answer changes:

1. Cost-plus contracts. If you're working under a cost-plus or "time and materials plus a fee" agreement, the contract usually defines what counts as "cost." You'd likely need to pass the sub invoice through at cost and bill your management fee separately—or make sure the contract language explicitly allows a sub markup.

2. When the client asks directly. Answer honestly: "Yes, I use specialty subs for certain scopes, and I stand behind their work the same as my own." Most clients don't care about the markup number once they understand you're taking on the guarantee. The response that loses work isn't "I mark up subs"—it's getting evasive when someone asks a direct question.

The disclosure debate lives on contractor forums because it feels like a gray area. For standard fixed-price residential work, it isn't. Your markup is your margin, no different from any other business that adds overhead to what it buys.

How to show subcontractor costs on your quote

The core rule: never pass the sub's invoice amount as a line item at their cost. Once a client sees "Johnson Sheet Metal: $1,800" on your estimate, every conversation becomes about your markup, not about the value of a completed, guaranteed project.

Here's how to present it cleanly:

1. Bundle it into your overall scope price. Include the sub's marked-up cost inside a single project line. Example: "HVAC replacement with modified plenum and new flex distribution: $5,400." The customer sees a project price.

2. Show it as a specialty scope line at your price. If the sub work is genuinely distinct—say, you're an electrician pulling in a low-voltage sub for a home theater install—you can break it out as its own line: "Home theater low-voltage installation: $1,600." That's your price for that scope, not what you paid the sub.

3. If you itemize, itemize at your price throughout. "Electrical rough-in: $X" and "Low-voltage: $X" is fine. "Sub invoice (cost pass-through): $1,380" and "Markup: $220" is the transparency trap that invites negotiation on your margin.

What to do when the sub's quote changes before the job starts

Sub quotes expire. Material costs move. If you estimate a job in September based on rough numbers from a sub and they formally quote you in October, the gap can wipe your margin before you've turned a wrench.

Two habits that protect you:

• Get a written sub quote before you quote the customer. Even a short email from the sub with a price and a validity window is enough. Don't finalize your customer quote until you have a confirmed number from your sub.
• Build a coordination contingency on complex jobs. When you're pulling together two or more subs on a single project, add 5–8% to the combined sub total before applying your markup. It covers late re-quotes, scheduling gaps, and scope clarifications. It's absorbed into your overall project price—not a separate line item.

The same logic applies to materials on volatile-cost jobs. How to protect your materials markup when prices keep rising covers the escalation-clause approach in more detail.

Takeaways

• Subcontractor markup isn't pure profit—it covers coordination time, insurance exposure, administrative overhead, self-employment tax (15.3%, per the IRS), and risk.
• A 15% markup on sub work is a defensible floor for most solo contractors on standard residential jobs once you account for SE tax and basic coordination cost.
• For fixed-price residential contracts, you're not required to disclose the sub markup to the client—but answer honestly and directly if asked.
• Never show the sub's invoice as a cost pass-through line item on your estimate; present your price for each scope.
• Lock in written sub quotes before quoting the customer, and build a contingency into multi-sub projects.

Quoting a job that involves a sub

When a job goes multi-trade, it's easy for the numbers to get messy—especially if you're building estimates in a spreadsheet and manually tracking sub costs alongside your own labor and materials. It's also where markup mistakes are most likely to slip through.

JobEstimator lets you add sub scopes as line items, apply your markup consistently, and generate a clean customer-facing PDF without any of the underlying cost detail showing through. Plans start at $39/mo. If the next job involves a sub, run the quote in the tool before you send anything to the client—it's the simplest way to make sure your markup is actually in the number you send.