Construction job costing: How to track estimated vs. actual costs

You quoted a remodel at $26,000 and figured $20,000 in costs. Six grand in expected profit.

Then you opened the wall. The framing needed repairs, the crew put in 30 extra labor hours, and you ran short on lumber. You also needed another dumpster pickup.

By the time the job finished, costs had climbed to $22,600. Your expected $6,000 profit was down to $3,400.

Construction job costing shows you where the extra $2,600 went. It tracks labor, materials, subcontractors, equipment, and overhead against each job so you can compare actual costs with your estimate.

You can use a spreadsheet or job management software. Either way, you’ll need to collect costs as work happens. A stack of receipts collected three weeks after the job closes makes it harder to pinpoint when the budget started slipping.

What is construction job costing?

Construction job costing is the process of tracking expenses for an individual construction project.

Every labor hour, material purchase, subcontractor bill, and other job expense gets assigned to the work that caused it.

That gives you more useful information than your company’s total monthly spending. You can see which jobs are making money, where costs are running high, and which estimating assumptions need work.

Job costing vs. construction estimating

Estimating determines what a job should cost before work begins. Job costing measures what it actually costs.

Your estimate becomes the starting budget. Once construction begins, actual labor hours, purchases, and invoices tell you how closely the work follows that budget.

If you’re preparing a bid, our guide on how to estimate construction costs and price a job covers the process.

Construction job costing example: Estimated vs. actual costs

Take a $26,000 residential remodeling job. The work includes demolition, framing repairs, drywall, finish carpentry, and subcontracted electrical and plumbing work.

You estimated $20,000 in costs, including allocated overhead. That left $6,000 in expected profit.

The job finishes with the following costs:

Fictional example. The original customer price remains $26,000, and all costs in the table are assigned to the job.

Your costs increased 13% over the original budget.

Job profit = Revenue - Job cost

$26,000 - $22,600 = $3,400

Your margin dropped from 23.1% to 13.1%. The $2,600 overrun consumed about 43% of the profit you’d expected.

Where did the extra $2,600 go?

The crew worked another 30 hours at a loaded labor cost of $40 per hour. That added $1,200.

Additional lumber and hardware cost $600. Another dumpster pickup added $200. The extra labor hours also increased allocated overhead by $600, using a rate of $20 per labor hour.

That accounts for the full $2,600 difference.

Hidden framing damage could explain some of the labor and materials. Poor production estimates could explain another part. The cost report needs enough detail to tell them apart.

How to track construction job costs in 7 steps

Step 1: Save the original estimate as your job budget

Before work starts, keep the approved estimate with its quantities, labor allowances, material prices, and subcontractor quotes.

Break the budget into categories you can track during construction.

For our remodel:

• Labor: $6,000
• Materials: $7,000
• Subcontractors: $3,000
• Equipment and disposal: $1,000
• Allocated overhead: $3,000

Total estimated cost: $20,000.

Keep a copy of the original budget when the scope changes. Approved additions should have their own costs and selling prices so you can see how the budget developed.

If you’ve included contingency, show it separately. A $1,000 contingency allowance becomes an actual expense only when you spend the money.

Step 2: Set up cost categories and codes

Your estimated and actual costs should use the same categories.

If dumpster fees were estimated under equipment and disposal, record the invoices there too. Otherwise, the report might show a materials overrun and an equipment saving simply because expenses were recorded under different headings.

For more detail, assign cost codes to types of work.

A bathroom remodel probably doesn’t need 50 cost codes. Start with the categories that help you compare the estimate with what your crew spent.

Using the same codes on similar jobs also makes it easier to compare labor and material costs when the next bid comes along.

Step 3: Track actual labor hours

Suppose your labor budget is $6,000 and your loaded labor cost is $40 per hour.

Estimated labor hours = $6,000 / $40 = 150 hours

Your crew records 180 hours.

Actual labor cost = 180 x $40 = $7,200

You’ve spent $1,200 more on labor than estimated.

Record who worked on the job, how long they worked, and what they were doing. If most of the extra hours went into framing repairs, you’ll want to know that before adjusting your standard drywall production rate.

The $40 rate in this example includes wages and employer labor burden, such as payroll taxes and workers’ compensation. Company overhead is allocated separately in Step 5. Use our free labor cost calculator to calculate wages and employer labor burden before setting your hourly labor cost.

For help calculating your own labor rate, see how to calculate construction labor costs.

Get the hours recorded each day. By Friday, your crew may remember working late on Tuesday, but the exact hours and tasks can be harder to reconstruct. If you’re recording hours manually, our free contractor timesheet generator lets you record work dates and hours and download the completed timesheet.

Cinderblock’s Build plan includes employee time tracking and job costing, so contractors can track labor hours and job expenses in the same system.

Step 4: Capture purchases and subcontractor costs

The supplier invoice for $4,000 usually reaches the office. It’s the $85 hardware run that disappears.

A crew member buys fasteners on the way back to the job. The receipt sits in the truck console. Two weeks later, somebody has to figure out which project used them.

Set a simple rule for field purchases: record the job, supplier, amount, and receipt when the purchase happens. Take a photo of the receipt and send it to whoever handles the job records.

For subcontractors, record the agreed amount, invoices received, and work still outstanding.

Suppose a subcontractor has a $3,000 agreement and has invoiced $1,000 so far. The remaining $2,000 belongs in your forecast of future costs. Counting the entire $3,000 commitment as an actual expense and then adding the invoice would inflate the job total.

Materials need the same attention. Record supplier credits, returns, delivery charges, and materials transferred between jobs. For supplier orders, our free purchase order generator lets you document materials, quantities, and agreed prices before the invoice arrives.

Cinderblock lets you attach files and photos to jobs. On the Build plan, you can also use purchase orders linked to jobs and vendors and record manually entered job costs.

Step 5: Allocate overhead to the job

Labor and materials are only part of the cost. Office staff, insurance, rent, accounting, and other operating expenses still have to be covered.

One way to allocate overhead is by productive labor hour.

Suppose you budget $120,000 in annual overhead across 6,000 productive labor hours.

Overhead rate = $120,000 / 6,000 = $20 per labor hour

Our remodel was estimated at 150 labor hours:

150 x $20 = $3,000 in estimated overhead.

The crew actually worked 180 hours:

180 x $20 = $3,600 in allocated overhead

Those extra 30 hours added $600 to the overhead allocation.

That doesn’t mean the business automatically paid another $600 in rent or office expenses. It means the job was assigned another 30 hours’ share of overhead using the contractor’s allocation method.

Your real overhead bill gets checked against the business’s total expenses.

Keep payroll burden in your loaded labor rate and company operating expenses in the overhead pool. Counting the same expense in both will inflate your job costs.

Our guide on allocating contractor overhead to each job explains how to calculate an overhead rate and apply it consistently.

Step 6: Review costs and forecast the remaining work

For longer jobs, review costs weekly. On smaller projects, check them at major milestones. Labor hours and purchases should be recorded as they happen so the review uses current numbers.

Look at actual spending, outstanding purchase commitments, subcontractor work, and the tasks still unfinished.

Say your remodel is roughly 40% complete and you’ve spent 35% of the budget. That sounds comfortable until you realize the expensive finish work is still ahead.

Estimate what the remaining work will cost.

Forecast final cost = Actual cost to date + Estimated cost to complete

Partway through our remodeling job, you’ve recorded $12,000 in actual costs. After checking the remaining labor, materials, subcontractor work, equipment, and overhead, you estimate another $10,600 is needed.

The remaining-cost estimate includes outstanding commitments that haven’t already been recorded as actual expenses.

Check whether the crew can complete the remaining tasks within the expected labor hours. Confirm material quantities and supplier prices before ordering. Ask subcontractors what work and invoices are still outstanding.

Update the forecast as the job progresses. If the customer approves additional work, compare the forecast with the revised budget.

Step 7: Close out the job and review the differences

Before closing the job, check for missing supplier invoices, subcontractor balances, labor hours, equipment charges, and credits.

Compare actual costs with the original budget and any approved revisions. Keep a short note explaining significant differences.

For the remodel, the closeout note might read:

“Framing required 30 additional labor hours after damaged studs were exposed. Material takeoff also missed lumber and hardware. One additional dumpster pickup was required.”

If some of those costs belonged to approved additional work, record that separately.

The next person preparing a similar estimate can see what caused the difference without having to track down the crew leader months later.

How to calculate construction job cost variance

A cost variance shows how far your spending differs from the budget.

For a straightforward overrun calculation:

Cost overrun = Actual cost - Budgeted cost

For the remodel, $22,600 - $20,000 = $2,600 over budget.

To calculate the percentage:

Cost overrun (%) = (Actual cost - Budgeted cost) / Budgeted cost x 100

$2,600 / $20,000 x 100 = 13% over budget.

You can do the same calculation for individual categories. Labor exceeded its $6,000 budget by $1,200, a 20% overrun.

Some accounting and project-control reports use the opposite sign convention, showing negative cost variance when spending exceeds the budget. Check the report’s formula before comparing figures.

How approved extra work changes the numbers

Now suppose the homeowner approved part of the framing repair as additional work before the crew started it.

This is an alternate version of the same remodeling job, using the same $22,600 in final actual costs.

The homeowner approves another $1,500 in the customer price. The approved work covers 15 of the 30 additional labor hours already recorded, plus some of the extra materials.

The added cost budget is:

Those costs are already included in the job’s $22,600 actual total. Part of the original overrun is now assigned to approved additional work.

The original and revised budgets look like this:

The job finishes with $22,600 in costs.

Against the revised budget, the overrun becomes:

$22,600 - $21,300 = $1,300

The final profit is:

$27,500 - $22,600 = $4,900

That gives you a 17.8% profit margin after the costs in our example.

The remaining $1,300 overrun consists of 15 additional labor hours ($600), their allocated overhead ($300), another $200 in materials, and $200 for the dumpster pickup.

Keeping the original and revised budgets separate lets you identify which costs were covered by approved work and which exceeded the revised estimate.

Record the added scope, cost allowance, customer price, and approval before the work proceeds. Keep that documentation with the job. Use our free change order generator to document the added scope and price for customer review before work begins.

What to include in a construction job costing spreadsheet

A spreadsheet can handle job costing for a small contractor running a few projects.

Start with one row per cost category or code.

Open commitments help build the remaining-cost forecast. If you’ve already included a subcontractor’s unpaid $2,000 balance in that forecast, adding it again will overstate the job’s expected cost.

You can also include transaction dates, suppliers, employee names, and receipt references.

Update the spreadsheet as expenses come in, then review it weekly for longer jobs or at major milestones for smaller ones.

Someone needs to own that process. If three crews are making purchases and nobody checks the records, your spreadsheet can look tidy while missing hundreds of dollars in expenses.

Use completed job costs to improve the next estimate

Our remodeling crew took 180 labor hours instead of the original 150.

Look at where those extra hours went before changing your estimating rates.

If 15 hours came from framing repairs the customer approved as additional work, separate those from the remaining 15 hours that exceeded the revised budget. Then check whether the original scope was underestimated or whether the crew ran into another problem.

Compare similar completed jobs to spot patterns. Repeated labor overruns on finish carpentry might mean your production rate is too aggressive. Regular material shortages could point to quantities missing from your takeoffs.

The same review can help you decide whether your pricing covers the work. Our guides on contractor markup and markup vs. margin for contractors explain how costs affect your selling price and profit.

Keep job costs current

Start with the original estimate, record costs against the job, and review the remaining work before the project closes.

A weekly cost review on a longer job can catch missing receipts, extra crew hours, and unbilled subcontractor work while there’s still time to adjust the plan. Keep the final report and its variance notes with the job records for the next estimate.