Change Order True-Cost Calculator

The four hidden costs every change order triggers

The materials + labor delta is the obvious number. The other three — schedule disruption, trade-coordination drag, and restocking — sit invisibly behind every change order and quietly compound. On a typical mid-project change, these hidden costs are 30-100% of the direct cost. Contractors who quote off the direct number eat the rest.

Schedule disruption — usually the biggest hidden cost

Daily burn ≈ 15% of contract total spread across the original calendar duration. A 5-day push on a $50k project pulls roughly $700/day × 5 days × 1.6 (burn + opportunity) = $5,600 in real cost — bigger than most homeowners' mental model of "it's just five days." If schedule disruption is your dominant hidden cost, the right negotiation move is a written timeline extension before discounting price — that transfers the cost from your books to the owner's calendar.

Trade coordination — sub idle costs are real money

When a change order pushes one trade back, the trades that were sequenced after them get idled. A plumber idled 3 days costs you ~$1,800 (truck, lead tech salary, partial helper) whether you cover it or whether they bill you for standby. HVAC and electrical run higher because of equipment carrying cost; framers and drywallers run lower. Itemize these in your quote; owners are more receptive when they see specific dollar lines than when they see a single bigger number.

Restocking — the easiest one to avoid

25% restocking is industry-standard at most supply houses; some specialty material runs 30-40%. On a change that returns $4,000 of material, that's $1,000 you'll never see back. The way to minimize this on future projects: order materials JIT for change-order-prone scopes (kitchens, baths, finish carpentry) instead of dropping the whole package at the start of the build.

The recommended quote

Recommended quote = trueCost × (1 + at-risk-margin). That holds the gross margin you priced into the underlying contract on the change order itself. If your contract is running at 18% margin and the trueCost is $8,000, the change should quote at $9,440 to keep the math whole. Quoting below that level dilutes margin on the rest of the work.

When the owner pushes back

Identify which bucket dominates and negotiate against THAT specifically. Schedule? Push for an extension. Trade? Itemize sub idle. Restocking? Propose using the materials in another scope. Direct? You're already at the cleanest possible quote — the math is the math.