Enter your weekly project count, average job value, materials cost percentage, and full operating costs to see your general contracting business's real monthly net profit — before you commit to the next bid.
You ran $80,000 through the business last month and there's $6,000 in the account. That's the moment most GCs realize "busy" and "profitable" are two different words. A 7.5% margin isn't a business — it's one change order dispute, one rained-out week, or one sub who walks mid-job away from a loss. This calculator puts every cost line against your revenue so you can see the real margin before you sign the next contract, not after. Enter Jobs Per Week, Working Weeks Per Month, Average Job Value, Materials/Parts Cost percentage, and flat monthly costs for labor, vehicle, overhead, and marketing.
The distinction this tool makes — and that most GC operators miss — is between gross revenue and what actually clears after materials and subcontractors. A $25,000 residential addition where materials and subs cost $17,500 is a $7,500 gross margin job, not a $25,000 profit job. The calculator processes your blended numbers to show that distinction at a business-wide level every month.
Materials cost and subcontractor cost: the real top-line leak
For a general contractor, the Materials/Parts Cost percentage captures two things simultaneously: direct materials (lumber, concrete, roofing, fixtures) and subcontractor payments (electrical, plumbing, HVAC, framing subs). Combined, these often run 50–70% of total revenue for a GC who manages trades rather than self-performing all work. A GC self-performing more trades will have a lower materials percentage but a higher labor cost.
On $75,000 in monthly gross revenue at 60% materials and sub cost, $45,000 leaves the business to pay suppliers and subcontractors before you have spent a dollar on your own staff, trucks, or office. The remaining $30,000 covers labor for your own team, vehicle fleet, overhead, and your own wages. That is the actual revenue pool available to run the business — which is very different from the $75,000 on your invoices.
The practical use of this calculator is seeing that $30,000 number and comparing it to your actual monthly fixed costs. If your combined labor, vehicle, and overhead total $24,000, you are netting $6,000 — a thin margin at $75,000 gross. If your fixed costs are $18,000, the same gross revenue yields $12,000, which is a much more sustainable operation.
Job margin versus company margin: why both matter
Experienced GCs often know their job margin — what a specific project nets after direct costs. Fewer track company margin — what the business nets after all overhead is allocated. The difference between job margin and company margin is your overhead absorption rate: how much of your fixed monthly costs each job must contribute.
A business doing 6 projects per month with $15,000 in monthly overhead needs each project to contribute $2,500 to overhead before generating profit. On an $8,000 average job with 35% materials cost, gross margin per job is $5,200. After $2,500 overhead allocation and $1,800 in allocated labor, the project nets $900. Scale that to 6 jobs and you are at $5,400 net for the month — roughly 11% of $75,000 gross.
The calculator does not do per-job overhead allocation, but it shows you the business-wide equivalent. Use it to establish what your company-level net margin is, then compare that to what you thought your project margins were. If company margin is significantly lower than project margin estimates, overhead is higher than you have been allocating.
Vehicle and fleet costs: the fixed obligation that does not flex
A general contracting business with two or three trucks, a trailer, and a job site trailer carries meaningful fixed vehicle costs: loan payments, commercial insurance, fuel, and maintenance. For a three-vehicle fleet, monthly vehicle costs commonly run $2,500–$5,000. These costs run regardless of how many jobs are active, which is why vehicle overhead is a particularly dangerous fixed cost during slow months.
Enter your Monthly Vehicle/Fuel cost honestly. Include every vehicle used in the business — even the owner's truck if it is used exclusively for work. Fuel alone can run $600–$1,500 per month for a multi-vehicle GC operation depending on geographic spread. Vehicle maintenance on work trucks adds another $400–$800 per month amortized over the maintenance calendar.
The business case for equipment ownership versus rental depends on your utilization rate. A compressor or trencher used on every job is worth owning; one needed twice a year is better rented. The calculator does not distinguish owned versus rented equipment, but the monthly cost should reflect your actual fleet — not an idealized version of it.
Overhead as an investment: what it should be buying you
Monthly Overhead for a GC typically includes general liability insurance, workers' compensation (or subcontractor certificates), project management software, licensing and bonding, tools and consumables, and a home or office allocation. These costs often run $2,000–$6,000 per month for a small to mid-size GC operation.
Overhead is not waste — it is the infrastructure that makes the revenue possible. Adequate insurance enables you to bid commercial work. Project management software reduces job delays. Bonding opens access to public contracts. The question is not how to minimize overhead but whether your gross revenue is sufficient to support it at a margin that makes the business worth running.
The Pricing Impact Analysis tab shows what job value is needed to generate 15%, 20%, or 25% net margin at your current overhead structure. If your current average job value puts you at 8%, the table shows you exactly what average ticket change — either through higher pricing or a different job mix — gets you to a sustainable range. GCs who answer that question before bidding tend to have fewer months where the revenue looks strong but the cash does not show up.
How to use the projections to plan a crew expansion
The Revenue at Different Job Volumes table shows net profit at different weekly job counts, which is the core planning tool for evaluating a crew expansion. If adding a second lead carpenter and a helper would enable 3 additional projects per month, the table shows whether the additional revenue at your current average job value covers the additional labor cost with margin left over.
More specifically: if your current crew runs 4 jobs per month and the expanded crew would run 7 jobs per month, the table shows net profit at both volumes. If the difference in net profit exceeds the additional monthly labor cost, the expansion is self-funding. If it does not, you need either higher average job values or a larger volume increase before the expansion makes financial sense.
Most GC operators considering expansion are already running at capacity — which means the expansion is not optional but the timing matters. Use the tool to determine the minimum number of additional jobs per month the expansion must generate to be immediately profitable, not just to cover costs over time. Run your real numbers before the next bid walk: it's free, no login, and it'll tell you in 30 seconds whether the job you're about to sign actually pays you or just keeps you busy.
How to use it
- Enter Jobs Per Week and Working Weeks Per Month — your realistic average, including slower weeks and jobs that run longer than expected.
- Set Average Job Value ($) to your actual monthly revenue divided by total projects completed — not your bid amounts.
- Enter Materials/Parts Cost (%) as your combined direct materials and subcontractor cost as a percentage of total revenue.
- Fill in Monthly Labor Cost ($), Monthly Vehicle/Fuel ($), Monthly Overhead ($), and Monthly Marketing ($).
- Read Profit Per Job, Profit Margin, Net Profit, and Monthly Revenue — then use the Pricing Impact tab to find the average job value that hits your target margin.
Who it's for
- GC comparing residential renovation versus commercial tenant improvement margins — Models residential at 4 jobs/week averaging $3,500 with 55% materials cost versus commercial at 1 job/week averaging $18,000 with 62% materials cost, finding commercial nets $2,100 more per month despite 70% fewer jobs.
- Owner evaluating a move from subcontracting to self-performing — Reduces materials/sub percentage from 65% to 45% while adding $8,000/month in labor for a framing crew, and finds self-performing adds $4,200/month in net at current volume — if the crew stays fully utilized.
- Contractor preparing a business line of credit application — Exports a monthly revenue, cost breakdown, and net margin projection to provide a bank with documented business financials rather than verbal estimates.
- New GC setting minimum project size policy — Finds the project value at which net margin drops below 10% given current overhead, and establishes that as the minimum bid threshold — stops taking unprofitable small jobs.
Key terms
- Materials/Parts cost percentage
- The combined share of gross revenue paid to material suppliers and subcontractors. For a general contractor managing trades, this is typically the largest single cost category — often 50–70% of revenue.
- Overhead absorption rate
- The portion of fixed monthly overhead that each project must cover. Calculated as total monthly overhead divided by monthly project count. Used to set minimum job sizes and pricing floors.
- Profit per job
- Total monthly net profit divided by total jobs completed in the month. The per-project efficiency metric for a contracting business.
- Gross margin
- Revenue minus materials and subcontractor costs, before labor, vehicle, and overhead are subtracted. The revenue pool available to run the contracting business.
Frequently asked questions
Should subcontractor payments go in Materials Cost or Labor Cost?
Subcontractor payments are best included in Materials/Parts Cost (%) since the tool treats that as a blended percentage of revenue. This keeps your Labor Cost field for your own employees' wages and payroll taxes. The blended materials-plus-subs percentage is what matters for the profit model — separating them is a bookkeeping choice that does not change the margin calculation.
What is a healthy net margin for a general contractor?
For a GC managing mostly residential work, net margins of 8–15% after overhead and owner wages are typical for a well-run operation. Commercial and specialty GCs with long-term project contracts sometimes run 5–10% net on higher absolute revenue. Below 6% net is fragile — one bad project, a slow month, or an unexpected cost can eliminate the year's profit.
How do I handle jobs that span multiple months?
For ongoing multi-month projects, estimate the monthly revenue recognized as work progresses and enter that as the effective monthly revenue. Alternatively, divide total contract value by expected project months and use that as your working monthly average. The tool models monthly cash flow — for long projects you may need to account for billing milestones rather than completion-based revenue.
Why is my gross revenue high but net profit always feels thin?
The most common explanation is that materials and subcontractor costs are higher than estimated, overhead has grown without a corresponding revenue increase, or the owner is not paying themselves a market wage (making the margin look better than it is). Enter your fully-loaded costs including a real owner wage and you will likely see the margin compress toward the truth.
Should I include general liability and workers' comp in Overhead or Vehicle?
Insurance — both general liability and workers' comp — belongs in Monthly Overhead since it is a fixed or near-fixed monthly cost tied to business operations rather than vehicle usage. Commercial auto insurance goes in Vehicle/Fuel since it is directly tied to the vehicles.