How to build an overhead rate for a job shop or trades business

"We're busy but we're broke" is the most common sentence I hear from job-shop and trades owners, and the cause is almost always the same: jobs are priced on materials and labor, and the shop, trucks, insurance, and office are supposed to come out of what's left. They don't. An overhead rate is how you put those costs into the price of every job before you quote it, so the margin on the estimate is the margin you actually keep.

Step 1: define the overhead pool

Overhead is every cost of running the operation that can't be traced to a specific job. The pool is the annual total. Pull last year's P&L and sort every expense line into one of three buckets:

• Direct cost (not overhead): materials, direct labor and its burden, subcontractors, job-specific equipment rental, permits. These are already in the job.
• Production overhead (in the pool): shop rent and utilities, shop supplies, small tools, equipment depreciation and repairs, vehicle costs, shop supervision, indirect labor like a shop helper or a dispatcher, production software, uniform and safety costs, general liability and property insurance.
• General and administrative (your call): owner's salary, office staff, accounting and legal, marketing, office rent. Some shops put G&A in the pool so every job carries its full share; some keep it separate and add it as a markup on top. Either works as long as you're consistent. For a business under a few million in revenue, one combined rate is simpler and harder to misapply.

Watch the direct-labor line. If field or shop wages are sitting in operating expenses, pull them out to cost of goods sold before you build the pool, or you'll be allocating labor to itself. The chart of accounts has to separate direct from indirect labor for any of this to work.

Adjust the pool for the year ahead: known rent increases, an added truck, a planned hire. The rate is forward-looking because it's used on quotes for next year's work.

Step 2: pick the allocation base

The base is the measure of activity that drives overhead. The right base is the one that, when a job uses more of it, the shop costs more to run. The candidates:

For most job shops and trades businesses, direct labor hours is the answer. If you have one department that's clearly machine-driven, give it its own rate on machine hours. Don't build five departmental rates for a twelve-person shop; the precision is fake and nobody will maintain it.

Step 3: do the math

Rate = overhead pool ÷ expected base. Use the hours you expect to bill to jobs, not the hours you'll pay for. The difference matters.

Call it $50. If the shop had used paid hours (12,480) instead of productive hours, the rate would be $38.94, and every job would be under-recovering overhead by about $11 an hour. That one mistake, using paid hours instead of productive hours, is the most common reason a calculated rate doesn't cover the shop.

Now the fully loaded labor cost per hour:

Average direct wage                     $28.00
Labor burden (taxes, WC, benefits ~24%)   6.72
Overhead rate                            50.00
                                        ------
Fully loaded cost per labor hour        $84.72

That's the number that goes into estimating. A job you quote at $75 an hour for labor is losing money before materials, and the P&L will confirm it at year-end, just too late to do anything about it.

Step 4: apply it

The rate is applied in two places:

• Estimating. Every estimate carries labor hours × fully loaded rate, plus materials and subs with their own markup, plus profit. The profit line is now real profit, not the pool you're hoping covers rent.
• Job cost reporting. In QuickBooks, you can apply overhead to jobs with a zero-dollar item or a monthly journal entry that debits an "applied overhead" line in job costs (by job) and credits an "overhead applied" contra account in operating expenses. That gives you job profitability after overhead without ever moving actual overhead into COGS, which keeps the P&L clean. Many shops skip the ledger entry and apply the rate only in estimating and a job-margin spreadsheet; that's fine for a smaller operation, as long as somebody is actually comparing estimated to actual by job. The job costing guide covers the item setup.

Step 5: true it up

At year-end, compare overhead applied (hours × rate) to actual overhead spent. The difference is over- or under-applied overhead, and it tells you something:

• Under-applied (actual higher than applied): either the pool grew, or productive hours came in below plan. Both mean next year's rate goes up, and this year's job margins were overstated.
• Over-applied (applied higher than actual): you ran leaner or busier than planned. Job margins were understated. Rate can come down, or you can hold it and bank the cushion.

For the books, the difference is usually closed to cost of goods sold at year-end if you've been applying overhead through the ledger. For the business, the point is the recalculation: new pool, new productive hours, new rate, every January. A rate that hasn't been recalculated in three years is wrong in a direction you can't see.

The owner's test: add up a year of labor hours on invoices and multiply by the overhead rate. If that's less than what the shop actually cost to run, you've been paying the difference out of profit, every job, all year.

Common mistakes

• Using paid hours as the base instead of productive, billable-to-jobs hours
• Leaving the owner's shop time out of direct labor while including the owner's salary in the pool
• Letting direct labor sit in operating expenses so it gets allocated to itself
• Building departmental rates for a shop too small to track them
• Pushing actual overhead into COGS by journal entry so the "job margin" on the P&L looks right and gross margin stops meaning anything
• Never recalculating; the rate from the year you had three trucks is still running the year you have six

Common questions

General guidance on cost allocation for management purposes, not accounting, tax, or legal advice. Overhead treatment for tax inventory costing (Section 263A and related rules) follows different requirements; confirm with your preparer.