How to Calculate the Total Cost of a Job (Full Formula)
I have run this exact formula on a $900 repair and on a $42,000 remodel that taught me the hard way what happens when you leave pieces out. The formula itself is short. Getting every real dollar into it is the actual job.
The formula, term by term
Six pieces make up total job cost. Miss one and your job looks more profitable than it is — right up until the bill for the thing you forgot shows up.
- Direct labor, loaded.Not just the hourly wage. "Loaded" means the wage plus payroll taxes, workers comp, and any paid time that isn't billable to the job — drive time, load-out, lunch on the clock if that's how you pay it. A $22/hr worker can cost $28–30/hr loaded once taxes and comp are in. Use the real loaded number, not the number on the pay stub.
- Materials.Everything bought for the job — lumber, tile, fixtures, hardware, the caulk and screws that never make it onto a proper line item because they're "small." Small adds up across a job.
- Subcontractors.Every sub's invoice, in full, whether they bill weekly or at the end. A sub you haven't been billed for yet is still a cost you owe — a plumber who did the rough-in three weeks ago but hasn't sent a bill is a committed cost the job is carrying right now, whether it shows up in your books today or not.
- Equipment and rentals.A rented lift, a dumpster, a compressor you don't own — anything rented or run specifically for this job.
- Permits and fees. Permit costs, inspection fees, plan review fees — often paid once, up front, and then forgotten by the time the job wraps.
- Overhead share. The slice of your truck payment, insurance, software, and shop rent that this one job has to carry. This is the piece contractors skip most often, because none of it shows up as a receipt tied to the job.
Overhead share: don't reinvent it here
Overhead is its own calculation — what it is, the four types, and how to find your own rate instead of guessing at one — and I've written the full method separately so this post doesn't repeat it badly. Short version: total your annual costs that aren't tied to any one job, divide by annual revenue, and that percentage gets applied to every job's direct costs before profit. Read construction overhead for the full method and a worked ledger.
Markup vs. margin, in two sentences
Markup is profit as a percentage of cost; margin is profit as a percentage of price. The two numbers are never equal above 0%, and using one where you mean the other is the single most common pricing mistake — see markup vs. margin for the conversion table and why a 30% markup only produces a 23% margin.
Three worked examples
Same formula, three sizes. The first two are labelled examples with round numbers so the math is easy to follow. The third uses the real numbers from a job I've written about in full. In all three, notice that overhead share is calculated on thedirect cost total (labor plus materials plus subs plus equipment plus permits) — never on the price, and never skipped just because the job is small.
Example: a $900 repair
| Line | Amount |
|---|---|
| Direct labor (3 hrs loaded at $30/hr) | $90 |
| Materials | $120 |
| Subcontractors | $0 |
| Equipment/rentals | $0 |
| Permits/fees | $0 |
| Overhead share (18% of $210 direct cost) | $38 |
| Total job cost | $248 |
| Price at 30% margin | $354 |
Example: a $9,000 bath refresh
| Line | Amount |
|---|---|
| Direct labor (loaded) | $2,400 |
| Materials (tile, fixtures, vanity) | $2,650 |
| Subcontractors (plumber, electrician) | $900 |
| Equipment/rentals (dumpster) | $280 |
| Permits/fees | $150 |
| Overhead share (18% of $6,380 direct cost) | $1,148 |
| Total job cost | $7,528 |
| Price at 30% margin | $10,754 |
The real one: a $42,000 bathroom remodel
I priced a bathroom remodel at $42,000 expecting a 30% margin. When the job closed, the real margin was 12% — not because the price was wrong, but because $7,500 in receipts never made it into the job cost while the work was happening. They were real costs, just uncounted ones, and uncounted costs still get paid out of profit whether you tracked them or not. I wrote the full breakdown, line by line, in the $42,000 bathroom remodel post — this is the one job number in this post that isn't a rounded example, because it actually happened.
What people forget
None of these show up as a single obvious receipt. They're the reason a job's "total cost" on paper is usually lower than its real total cost.
| Forgotten cost | Why it disappears |
|---|---|
| Drive time | Feels like overhead, not labor — but it's paid time either way |
| Dump fees | A cash ticket at the landfill, easy to lose before it reaches the books |
| Second trips | The supply-house run for the part that was wrong or missing — rarely logged as a job cost |
| Consumables | Caulk, screws, blades, tape — bought in bulk, never split out per job |
| Permit runs | The half-day spent at the permit office, not just the fee itself |
| The owner's own hours | Estimating, driving, and admin time on your own job — unpaid on paper, still a real cost |
Cost per square foot as a sanity check
Once you have a total job cost, dividing it by square footage gives you a rough number you can compare job to job — total job cost ÷ square feet = cost per square foot. On the $42,000 remodel above, the real cost came to $36,960 once the missing receipts were in. If that bathroom was 60 square feet (a made-up size for the math), that's about $616 per square foot in total job cost, not price.
Treat that number as a sanity check, not a price. Two bathrooms the same size can cost wildly different amounts depending on finish level, how far the plumbing has to move, and how much of the existing tile has to come out first. Cost per square foot tells you "does this number look like the same kind of job I did last time," not "what should I charge." Price the job from its real formula above; use cost per square foot to catch a number that looks off before you commit to it. If a new bid comes in at half the cost per square foot of your last three similar jobs, that's not a sign you found a cheaper way to build — it's a sign to go back through the formula and find what got left out before you sign anything.
Doing this on a real job, with real receipts
The formula is simple. Keeping every real dollar flowing into it while a job is running is the actual work, and it's the part that breaks first — a receipt left in the truck, a sub's invoice that arrives three weeks late, an hour of drive time nobody wrote down. I built Job Cost Pro because I was losing that fight with a shoebox of receipts. Snap a receipt at the counter and the AI reads it and files it to the job automatically; say an expense out loud with voice-to-expense when your hands are full; watch live profit and margin update per job instead of finding out at tax time. Crew time on the Contractor tier feeds straight into your labor cost, so the loaded-labor line above stops being a guess. Free on the App Store: 3 projects, 50 receipts a month, full AI scanning, no card. Get it here. Want the calculator to do the arithmetic above for you right now? Try the job cost calculator or the labor cost calculator for the loaded-labor piece specifically.
One last thing, said plainly:this is not tax or accounting advice. I'm a contractor who built a tool to stop losing receipts, not your CPA. The formula above will get your job cost close to right; bring your actual numbers to a professional for anything that touches your taxes or your books.
FAQ
What is the formula for job costing?
Total job cost = direct labor (loaded) + materials + subcontractors + equipment/rental costs + permits and fees + your share of overhead. Add profit on top of that total to set your price. Markup and margin describe that profit differently — see the markup vs. margin post for the conversion.
What is included in total job cost?
Six pieces: loaded direct labor (wage plus taxes, comp, and unbillable paid time), materials, subcontractor invoices, equipment and rental costs, permits and fees, and a share of your overhead. Costs that never generate a normal receipt — drive time, dump fees, second trips, consumables, the owner’s own hours — belong in the total too, even though they’re the easiest ones to forget.
How do you add overhead to a job?
Calculate your overhead rate first (annual costs not tied to any single job, divided by annual revenue), then apply that percentage to the job’s direct costs before adding profit. A job with $10,000 of direct costs and an 18% overhead rate carries $1,800 of overhead before any dollar counts as profit. The full method is in the construction overhead post.
Is markup the same as margin?
No. Markup is profit as a percentage of cost; margin is profit as a percentage of price. A 30% markup on a $10,000 job produces $3,000 of profit and a price of $13,000 — but that profit is only 23% of the $13,000 price, not 30%. Confusing the two is one of the most common pricing mistakes contractors make.
How do I calculate job cost per square foot?
Divide total job cost by square footage. It’s a rough sanity check for comparing similar jobs to each other — not a way to price a job, since finish level, plumbing moves, and demo scope can make two same-size rooms cost very different amounts. Price from the full job cost formula; use cost per square foot to catch a number that looks off.