Change Order Pricing Calculator
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Runs entirely in your browser — your numbers never leave this page.
How it works
Change orders are where contracting profit goes to die — or gets made. The work is real, but contractors routinely underprice extras: forgetting markup on materials, eating the rescheduling cost, or doing it on a handshake and fighting about it later.
The formula is simple: direct cost × (1 + markup) + disruption fee. Markup covers overhead, risk and profit — 15% for easy add-ons, 25% standard, 35% when the change rips up finished work or reshuffles your subs.
The non-negotiable rule: written, signed, priced before work starts. A one-page change order with scope, price and schedule impact takes five minutes and prevents five-figure disputes.
Frequently asked questions
What markup should I use on change orders?
15% for simple add-ons, 25% standard, 35% for disruptive changes (redoing finished work, rescheduling subs, rush timelines). Change orders carry more risk than base bids — price accordingly.
Should I charge for the disruption?
Yes — reshuffling subs, remobilizing, and delaying other jobs has real cost. A flat disruption fee ($250–2,500 depending on scale) makes the invisible visible.
Do I mark up materials or pass through at cost?
Mark them up. You source, warranty, transport and handle them — 15–25% is standard. Passing through at cost means you work for free on procurement.
What must a change order document include?
Scope of the change, price, payment terms, schedule impact, and signatures from both sides. Date it. Keep a numbered sequence (CO-001, CO-002...).
Can I refuse a change order?
Yes — especially ones that compromise code, safety, or your schedule. Offer the alternative in writing; never do extra work "as a favor" on a fixed-price job.
How do I handle "while you're at it" requests?
Smile, write it up, price it. Small freebies train clients to expect free work. If you choose to comp something small, note it as a $0 line item so the value is visible.
What if the client disputes the price?
Your signed original contract + written CO process is your leverage. Without documentation, it becomes your word against theirs — which is why the paperwork comes first.
Should change orders have different payment terms?
Often yes — many contractors require 50% upfront on change orders, especially for special-order materials. Do not finance the client's changes.
How do change orders affect the schedule?
State the impact explicitly: "+3 days" or "no impact." Undocumented delays become your fault at final walkthrough.
Can change orders rescue an underbid job?
Sometimes — extras at proper margins can restore profitability. But deliberately underbidding to win and profiting on changes is a reputation killer; bid honestly instead.