ES-04Estimating

Change Order Calculator

What to calculate next

Tools commonly used alongside this calculation

Explanation

A change order calculator prices added or revised work and applies the overhead and profit markup so the change is not done at a loss. A change order is a written amendment to the contract that adjusts the scope, price, and often the schedule. The price is built from the direct cost of the work — labor, material, equipment, and any subcontractor — plus a markup that covers your overhead and the profit the change should earn.

How a change order is priced

Start with the direct cost, then add overhead as a percent of that cost and profit on the running subtotal. Bond and insurance, if your contract carries them, go on top of the marked-up price. Use a realistic burdened labor rate for the labor line — the labor burden calculator turns a base wage into the fully loaded cost per hour, and the man-hours calculator estimates the added work behind it.

direct = labor + material + equipment + subcontractor
overhead = direct × OH% ÷ 100
profit = (direct + overhead) × profit% ÷ 100
total = direct + overhead + profit + bond
TermMeaning
directDirect cost to perform the changed work
overheadHome-office and field overhead, as a percent of direct cost
profitEarnings on the change, applied to the overhead subtotal
bondBond premium and insurance on the marked-up price (optional)

Markup vs. margin

Markup and margin are the most common change-order mistake. Markup is a percent of your cost; margin is a percent of the price you charge. Marking up a $1,000 cost by 20% gives a $1,200 price, but the profit is only $200 — a 16.7% margin, not 20%. To actually earn a target margin you have to mark up by more, using the conversion below. The Target margin mode does this back-calculation for you.

markup% = margin% ÷ (1 − margin% ÷ 100)
Target marginRequired markup
10%11.1%
15%17.6%
20%25.0%
25%33.3%

Typical overhead, profit, and bond rates

Most change orders carry a combined overhead-and-profit markup of 15% to 25%. The low 10% overhead / 5% profit figure many contracts assume rarely covers the true cost of a change, because small added jobs disrupt the schedule and carry coordination cost out of proportion to their size.

ComponentTypical rangeNotes
Overhead8–15%Of direct cost; supervision and home office
Profit5–15%Depends on project risk and market
Combined OH&P15–25%Most healthy change-order markups
Subcontractor markup5–15%Often capped by the contract on sub work
Bond & insurance1–3%Of the marked-up price, when required

Notes and limitations

Allowable markup is set by your contract — many spell out the exact overhead and profit percentages and cap the markup a general contractor may add on subcontractor work. Under AIA documents, a deductive (credit) change order usually returns the direct cost without profit, and net change orders net the adds against the deducts before markup. Always get the change order signed before performing the work, and remember that change orders are billed and held back like base-contract work — the retainage calculator shows how retention applies to the added amount.

Frequently asked questions