Margin, markup, changes, and job costing

Hourly Overhead Rate Calculation Example

A contractor projects $180,000 in annual G&A overhead and 9,000 billable field hours across its workforce:

$$\text{Hourly Overhead Rate} = \frac{\$180,000}{9,000 \text{ hours}} = \$20.00 \text{ per direct labor hour}$$

If a project requires 120 direct labor hours, the allocated company overhead is $2,400 (120 direct labor hours × $20.00).

Markup vs. Margin: The Critical Distinction

A common cause of contractor insolvency is treating markup and margin as interchangeable numbers.

• Markup is the percentage added to total cost to establish the price:

$$\text{Markup \%} = \frac{\text{Selling Price} - \text{Total Cost}}{\text{Total Cost}} \times 100\%$$

• Profit Margin on the Included Cost Base is the percentage of the selling price that remains as profit:

$$\text{Margin \%} = \frac{\text{Selling Price} - \text{Total Cost}}{\text{Selling Price}} \times 100\%$$

To price a bid to yield a target profit margin, divide total cost by $(1 - \text{Margin})$:

$$\text{Selling Price} = \frac{\text{Total Cost}}{1 - \text{Target Margin Rate}}$$ $$\text{Markup Rate} = \frac{\text{Margin Rate}}{1 - \text{Margin Rate}}, \quad \text{Margin Rate} = \frac{\text{Markup Rate}}{1 + \text{Markup Rate}}$$

Markup vs. Margin Conversion Reference Table

Step-by-Step Worked Mathematical Example

A residential hardscape project has the following estimated costs:

• Direct Materials: $8,400
• Burdened Labor (150 hours @ $32/hr): $4,800
• Equipment Rental: $1,600
• Indirect Job Costs (Permit, Disposal): $1,200
• Allocated G&A Overhead (150 hours @ $16/hr): $2,400
• Total Project Cost: $8,400 + $4,800 + $1,600 + $1,200 + $2,400 = $18,400

The contractor establishes a target 20% profit margin.

Flawed Contractor Calculation (Markup Error)

Multiplying cost directly by 1.20:

$$\text{Flawed Price} = \$18,400 \times 1.20 = \$22,080$$ $$\text{Actual Margin Earned} = \frac{\$22,080 - \$18,400}{\$22,080} = \frac{\$3,680}{\$22,080} = 16.67\%$$

Correct Mathematical Calculation

Using the proper margin formula:

$$\text{Correct Selling Price} = \frac{\$18,400}{1 - 0.20} = \frac{\$18,400}{0.80} = \$23,000$$ $$\text{Profit} = \$23,000 - \$18,400 = \$4,600$$ $$\text{Margin Verification} = \frac{\$4,600}{\$23,000} = 20.0\%$$ $$\text{Equivalent Markup on Cost} = \frac{\$4,600}{\$18,400} = 25.0\%$$

Changes, approvals, and cost records

LCB requires written construction contracts at $2,000 or more, aggregated by job site and owner over twelve months. Changes must be written and agreed to by both parties; signatures on a change order are not required. An accepted email or text can document agreement. Keep the description, quantity, revised price, and schedule impact together, and send the approved scope to the field crew before it performs the change.

Separate a material substitution from additional work. Replacing a unavailable specified shrub with an agreed equivalent can change the purchasing record without increasing plant quantity. Adding a second planting bed changes quantity, labor, disposal, and irrigation demand. Price the actual difference, including credits for removed scope, instead of automatically adding a percentage to the original contract. LCB contract checklist.

Job Costing, WIP Tracking, and Post-Job Audits

Estimating provides a projected budget; job costing tracks actual costs to verify financial performance.

• In-Progress Tracking: Field crew hours are recorded daily against specific cost codes (e.g., excavation, base preparation, paver setting, planting). Material invoices are coded directly to the active job ledger.
• Work-in-Progress (WIP): Compares actual costs against estimated completion percentages to prevent unbilled work or premature revenue recognition.
• Post-Job Audit & Variance Analysis: Compares estimated vs. actual labor hours and material consumption.

$$\text{Labor Variance} = \text{Actual Hours} - \text{Estimated Hours}$$

If 800 square feet of pavers was estimated at 20 sq ft/hour (40 hours) but required 56 actual hours (14.3 sq ft/hour), the audit flags a 16-hour labor overrun. Contractors use this data to identify causes (e.g., intricate cuts or equipment delays) and calibrate future bidding rates.

Application check

If the desired margin changes after an estimate is accepted, distinguish a new pricing decision from an error in the original cost estimate. Compare actual quantities, production, and overhead recovery first. A lower realized margin can arise from rework or cost growth even when the original selling-price formula was correct. Use the cost records to identify the source before changing every future bid.

The included cost base matters when naming a margin. Job gross profit commonly subtracts job costs before general business overhead, while operating profit also deducts that overhead. The worked bid includes allocated G&A in total cost, so its twenty-percent result is a profit margin on that stated full cost base; it is not a separate claim about financial-statement gross margin. Keep the same basis when comparing estimates with actual results.