A construction change order is a written modification to the original contract that adjusts the scope, price, or schedule of a project. The contractor and the client both sign it before the changed work begins.
Change orders are tough. It is hard to get everyone on the same page, and harder still to get paid what the work is actually worth. It would be easier if they never came up, but the nature of remodeling means most projects will have at least a few. Here is the problem: you could be losing money on every one of them and not even know it.
A construction change order looks simple to price. Figure your costs, mark them up, get a signature. But there is a hidden cost buried in most change orders that quietly eats your profit, and I want to show you how to find it.
What is a construction change order?
A construction change order is a written agreement that modifies your original contract. It adjusts the scope, the price, the schedule, or all three, and both you and the client sign it before the changed work starts.
Change orders come up whenever the job moves outside what the contract and plans already cover: a client upgrade, a design change mid-project, or an unforeseen condition you uncover once walls are open. Each one needs to capture three things clearly: what is changing, what it costs, and how many days it adds.
Getting that math right matters for two reasons. The obvious one is margin. The less obvious one is disputes. A vague or under-priced change order is where profit leaks out and where arguments with clients start.
How to calculate a construction change order, step by step
Most remodelers know the basics. Here they are in order, so nothing gets skipped:
- Confirm the work is outside the original scope. If it is not in the contract or the plans, it gets written up as a change order.
- Add up your real costs. Materials, labor, and any subcontractor pricing for the added work.
- Apply the same markup as your original contract. If your contract runs a 50% markup, the change order does too. Do not discount it because the client pushes back.
- Add the schedule impact. Count the extra days the change adds to the job, including the disruption days covered below.
- Attach overhead to every added day. Labor days pick up overhead automatically through your markup. Disruption days do not, so you have to add it yourself.
- Total the new contract price. Original contract plus all change orders equals the new price.
- Get a signature before any work starts. No signature, no work.
- Collect the money before the work is done, and hold your price.
The cost most remodelers miss: disruption days
What is almost always missing from the math is the cost of what I call disruption days. These are days that carry no labor cost of their own, but still hit the job because of the disruption a change causes.
This matters more now than it used to. Everyone is busy. You cannot just reschedule trades or slide material deliveries to recover lost time. One day of changes can slow a job by a week, because the painter you bumped is now booked two weeks out. Those idle days still cost you, and nothing in your standard change order math accounts for them.
Figure your overhead per day, per job
Start by working out what a single day of a single job costs you in overhead. Take your annual overhead, divide by your working days, then divide by the number of jobs you run at once.
Estimated Numbers:
Figure | Amount |
Annual overhead | $600,000 |
Working days per year | 250 |
Overhead per day | $2,400 |
Jobs running at once | 4 |
Overhead per day, per job | $600 |
So every day a job runs, it carries about $600 of overhead in this example. When you price a change order, the labor days already absorb their share through markup. The disruption days do not, unless you add it.
(The figures above are an illustration. Swap in your own numbers, or use Remodelers Advantage benchmark data for current industry averages.)
Price the change order with disruption days included
Here is what a single change order looks like once you build the disruption days in. Say the changed work costs $4,000, you run a 50% markup, and the change pushes three disruption days onto the schedule:
Line item | How to price it | Example |
Materials and labor | Your actual cost | $4,000 |
Markup | Same percentage as the original contract (50%) | $2,000 |
Added labor days | Overhead already included in markup | (in labor) |
Disruption days | Overhead per day, per job × days (3 × $600) | $1,800 |
Change order price | Add it up | $7,800 |
Leave the disruption days out and you write that same change order for $6,000. That $1,800 gap is real overhead you will absorb whether you charge for it or not.
What disruption days do to your bottom line
If that overhead is not recouped somewhere, your company eats it. And it gets worse: by stretching a job out with days that carry no revenue, you push back the start of the next project and lose the profit that job would have produced. That is lost opportunity profit on top of the lost overhead.
Run it at the company level. Same business, targeting $2 million in revenue with overhead at 30%, across 250 working days. That means you need to produce $8,000 a day to hit the target. Now say extensions cost you 30 production days across the year that never get billed through marked-up labor:
Figure | On plan | With 30 lost production days |
Revenue produced | $2,000,000 | $1,760,000 |
Annual overhead (fixed) | $600,000 | $600,000 |
Overhead as % of revenue | 30% | 34.1% |
Net profit impact | baseline | about 4 points lower |
Overhead is mostly fixed. Produce less revenue against the same overhead and that overhead eats a bigger share, roughly four points of net profit in this case. Those are the kind of leaks that also show up in your WIP schedule and your over and under billing, and they are first cousins to slippage.
Some of you are thinking you cannot add $600 a day to every change order. You are probably right, and some clients will not wear it. But the cost is real. So do this: calculate your overhead per day, per job. Write the number of disruption days on every change order. Recover what you can. Where you cannot, at least you will know exactly what each change is costing you.
If your change order pricing has drifted, comparing notes with other owners is one of the fastest ways to fix it. That is the kind of thing remodelers work through together inside Roundtables.
Frequently asked questions
How much should I mark up a change order?
Use the same markup percentage as your original contract. If the job is priced at a 50% markup, the change orders carry 50% too. Cutting the markup on change orders, which clients often push for, quietly erodes the margin you built the whole project around.
Who pays for change orders?
The client pays for changes they request or approve, which covers most change orders: upgrades, design changes, and added scope. Work to fix your own error is usually on you. Genuinely unforeseen conditions, like hidden rot or a code surprise, are typically billable to the client, but spell out in your contract how those get handled so there is no argument later.
What is the difference between a change order and a change directive?
A change order is a mutual agreement. You and the client both sign off on scope, price, and schedule before the work starts. A construction change directive is different: the owner instructs you to proceed with a change before the price and schedule are settled, and you reconcile the cost afterward from actual labor and material records. Directives keep urgent work moving, but they only apply if your contract allows them, so for most residential remodelers the signed change order is the safer default. (The formal AIA versions are documents G701 for change orders and G714 for directives.)
Put it to work
Take your next change order and run it through these eight steps with disruption days included. You will either get paid for time you used to give away, or you will at least know what you are choosing to absorb.
Want to pressure-test your pricing against other remodelers who run the same numbers? That is what happens inside Roundtables.
