Job Costing for General Contractors: The 3 Numbers You Must Track Daily

Effective job costing for general contractors requires tracking three daily metrics: estimated vs. actual labor hours, material waste percentages, and unbilled change orders. Failing to track your fully burdened labor in real-time means you won't know you lost money on a $50,000 kitchen remodel until the job is completely finished. By implementing a daily tracking system, you can catch margin fade on day three instead of day thirty.

Listen, if you are waiting until the final check clears to see if you made money on a build, you aren't running a construction business. You're buying a lottery ticket.

Most contractors practice what I call "autopsy accounting." They finish the job, pay the subs, sweep the site, and then look at the bank account to see what's left. If there's cash, they celebrate. If they are in the red, they blame the client, the weather, or the lumber yard.

Proper job costing for general contractors isn't an end-of-month accounting exercise for your CPA. It is a daily, field-level operational tool. It is how you steer the ship.

If you want to stop guessing and start running predictable, profitable projects, you need to strip away the complex software and focus on first principles. Here are the three numbers you must track every single day, why most guys get them wrong, and exactly how to fix it tomorrow morning.

1. Estimated vs. Actual Labor Hours (The Daily Burn Rate)

Labor is the most volatile variable on any job site. Materials sit there until you nail them together. Subcontractors give you a fixed price (usually). But your in-house labor? That is a ticking meter that bleeds cash every time a guy spends 45 minutes driving to Home Depot for a $6 box of screws.

Most Contractors Get This Wrong: Ignoring Labor Burden

The biggest mistake in construction estimating and job costing is tracking base pay instead of labor burden.

Let's say you pay your lead carpenter, Mike, $30 an hour. You estimate a custom deck will take him 40 hours. You budget $1,200 for labor.

Mike finishes in 40 hours. You think you hit your budget. You didn't. You lost money.

You forgot that Mike doesn't cost you $30 an hour. When you factor in:

• FICA/Medicare taxes (7.65%)
• Workers' Compensation (Let's say 12% for carpentry)
• General Liability Insurance (2%)
• State/Federal Unemployment (3%)
• Health insurance stipend ($400/month or ~$2.50/hr)
• Vehicle allowance/gas ($3.00/hr)
• Non-billable time (shop meetings, loading the truck—adds about 10% to the hourly cost)

Mike's true cost to your company—his labor burden—is actually $46.50 an hour.

That 40-hour deck didn't cost $1,200 in labor. It cost $1,860. If you didn't track the burdened rate, you just gave away $660 of your net profit. If you are wondering how much profit a general contractor should make, standard industry target is 10% to 15% net. A $660 leak on a small deck completely wipes that out.

How to Track It Daily

You cannot track labor in dollars on the job site; you must track it in hours.

Break your estimate down into cost codes (e.g., 01-Demo, 02-Framing, 03-Trim). If you budgeted 24 hours for framing, you need to know where you stand at the end of day one.

If Mike and his apprentice burn 16 hours on Tuesday, and the framing is only 30% done, you have a massive problem. You have 8 hours left in the budget, but 70% of the work remaining. Because you tracked this daily, you can intervene on Wednesday morning. Was the material staged poorly? Is the apprentice slowing Mike down? Fix it now. If you waited until Friday, the budget would be blown by 20 hours ($930 in burdened costs).

Actionable Step for Tomorrow Morning

Stop accepting timecards that just say "8 hours - Smith Job." Mandate that every timecard submitted by 4:00 PM includes specific cost codes. (e.g., "4 hours Demo, 4 hours Framing"). If they don't allocate the hours to a code, they don't get processed for payroll.

2. Material Waste Percentages (Reading the Dumpster)

Every estimate includes a waste factor. For hardwood flooring, it's typically 7% to 10%. For framing lumber, it might be 15%. For tile, depending on the pattern, it can be up to 20%.

But estimating waste and tracking actual waste are two different universes.

Most Contractors Get This Wrong: The Dumpster Drain

Contractors assume that if they ordered 15% extra material and the job got finished, everything went according to plan. But what if the crew made so many bad cuts that they used the 15% waste, ran out, and quietly went to the supplier to buy another 10% on the company account to finish the job?

Let's look at a high-end tile job. You are installing 500 square feet of $12/sq ft marble.

• You estimate 500 sq ft + 15% waste = 575 sq ft.
• Material cost: $6,900.

Your setter is sloppy. He miscuts around the shower niche, drops a box, and fails to plan his layout, resulting in tiny, unusable slivers at the walls. He ends up needing 650 sq ft to finish the job. That's a 30% waste factor.

That extra 75 sq ft cost you $900 out of pocket. To understand how devastating this is, you need to understand markup vs margin. If your company operates at a 10% net profit margin, you have to sell $9,000 worth of new work just to make up for the $900 your tile setter threw in the dumpster.

How to Track It Daily

Job costing for general contractors requires physical audits. You track material waste by looking at the cut pile and the dumpster at the end of the day.

If you are framing a house and you see 4-foot offcuts of $45 LVL beams in the scrap pile, your crew is pulling long stock for short spans instead of using the existing cutoffs. You are bleeding cash.

Track your material deliveries against your installed units. If 50% of the drywall is hung, but 70% of the boards you ordered are gone, you have a variance. You need to address it immediately.

Actionable Step for Tomorrow Morning

Walk your active job site and physically inspect the dumpster and the scrap pile. If you see usable offcuts of expensive material (Azek trim, clear cedar, copper pipe), take a picture, show it to your lead guy, and explain exactly how much money is sitting in the trash.

3. Unbilled Change Orders (The "While You're Here" Trap)

Scope creep is the silent killer of construction companies. It doesn't happen all at once; it happens in $200 increments.

"Hey Mike, while you have the wall open, can you move that outlet over two feet?" "Since you guys have the excavator here, can you quickly grade this little patch of dirt by the driveway?"

Most Contractors Get This Wrong: The Handshake Agreement

Contractors are people-pleasers. When the homeowner asks for a small favor, the lead carpenter says, "Sure, it'll only take 20 minutes."

But it's never just 20 minutes. Moving that outlet requires 30 minutes of labor, $15 in wire and boxes, and now the drywaller has to patch an extra hole, which costs you another $75. That "quick favor" just cost your company $135 in hard costs.

If you do that twice a week, you are giving away $14,000 a year in free labor and materials.

Worse, many GCs will do the work and tell the client, "We'll settle up at the end." When the end of the job comes, you hand the client a bill for $3,500 in extras. They get angry, claim they didn't know it would cost that much, and refuse to pay. You end up eating it to keep the peace.

How to Track It Daily

Unbilled change orders must be tracked on a daily job log. If the scope of work changes by even one inch, work stops until a price is attached to it and a signature is acquired.

If you subcontract work properly, you know that your subs will relentlessly charge you for change orders. If the plumber hits you with a $300 bill for moving a pipe that was in the way, you must pass that cost (plus your markup) to the client immediately. If you don't track this daily, the sub's invoice will arrive 30 days later, long after you've handed the final bill to the homeowner.

Actionable Step for Tomorrow Morning

Implement the "Zero-Tolerance Change Order Rule." Print out five blank change order forms and put them on clipboards in every company truck. Train your crew to use this exact script:

"I would love to take care of that for you, Mrs. Smith. Let me text the boss so he can send over a quick change order for approval, and as soon as you sign off, I'll jump right on it."

If it's not signed, it doesn't get built.

Real-World Example: Autopsy of a $50,000 Kitchen Remodel

Let's look at what this looks like on a job when you don't track these three numbers daily, versus when you do.

The Setup:

• Contract Price: $50,000
• Estimated Hard Costs (Labor + Materials + Subs): $35,000
• Target Gross Profit: $15,000 (30% margin)

The Reality (Without Daily Job Costing):

1. Labor: You estimated 120 hours for in-house carpentry. You budgeted at the $30/hr base rate ($3,600) instead of the $45/hr burdened rate ($5,400). You are already down $1,800 before the job starts. The crew hits a snag with out-of-plumb walls and takes 160 hours.
   • Real Labor Cost: 160 hrs x $45 = $7,200. (Variance: -$3,600)
2. Material Waste: The crew miscuts three sheets of $150 cabinet-grade plywood and ruins a bundle of custom trim.
   • Real Material Overage: $850. (Variance: -$850)
3. Unbilled Change Orders: The client asked for two extra can lights, a different cabinet pull style (which required redrilling), and asked you to paint the pantry to match. You did it on a handshake.
   • Unbilled Costs: $1,200. (Variance: -$1,200)

The End Result: You thought you were making $15,000. Subtract the labor variance (-$3,600), the material waste (-$850), and the unbilled extras (-$1,200). Your gross profit is now $9,350 (an 18.7% margin).

Once you subtract your company overhead (office rent, software, admin salary, marketing), which typically runs 15% to 20% of revenue, you actually lost money on this kitchen. You paid for the privilege of remodeling Mrs. Smith's house.

The Reality (With Daily Job Costing):

• Day 3: You check the daily labor log. The crew is 40 hours in but the walls aren't plumb yet. You catch the overrun early, jump on-site, and help them laser-level the strapping in 4 hours instead of letting them struggle for 2 days. You save 16 hours of labor.
• Day 6: You check the dumpster and see the ruined plywood. You realize the new apprentice's saw blade is dull and tearing out the veneer. You buy a $60 Diablo blade and stop the waste immediately.
• Day 12: The client asks for the extra can lights. Your lead guy pulls out the clipboard. The client signs a $450 change order. You capture the revenue.

By tracking the numbers daily, you protect your 30% margin and actually take home the $15,000 you planned on.

Building Your Daily Tracking System (Without Overcomplicating It)

You do not need a $500/month enterprise software suite to do this. You need a simple spreadsheet and discipline. Effective job costing for general contractors comes down to tracking units, not just dollars.

Set up a spreadsheet for every job with these six columns:

1. Cost Code: (e.g., 04-Drywall)
2. Description: (e.g., Hang and tape kitchen walls)
3. Estimated Units: (e.g., 32 Labor Hours / 40 Sheets of Rock)
4. Actual Units to Date: (Updated daily from timecards and delivery tickets)
5. Remaining Units: (Column 3 minus Column 4)
6. % Complete: (Subjective field estimate by the lead guy)

The Daily 4:30 PM Sync

Every day at 4:30 PM, you or your production manager must spend 15 minutes updating this sheet.

Compare Column 5 (Remaining Units) with Column 6 (% Complete).

If your sheet says you have 10% of your labor hours remaining, but your lead carpenter says the task is only 50% complete, a massive red alarm should go off in your head. You are about to blow the budget. You now have the power to fix it tomorrow morning before the money is permanently gone.

The Bottom Line

Construction is a game of margins, and margins are lost in the micro-details. A $50,000 job doesn't lose $5,000 all at once. It loses $50 an hour in inefficient labor, $100 a day in wasted materials, and $300 a week in undocumented favors for the client.

Job costing for general contractors is the only defense mechanism you have against margin fade. Track your fully burdened labor hours against your estimate. Audit your material waste by looking in the dumpster. Never lift a hammer on out-of-scope work without a signed piece of paper with a dollar amount on it.

Your Next Step: Open up the estimate for the job you are currently building. Calculate the fully burdened labor rate for the guys on that site right now. Multiply it by the hours they've worked so far this week. Compare that to the budget. If you are upside down, get in your truck tomorrow morning and go fix it.