To price a change order, price it exactly the way you priced the original job: material at your current replacement cost, labor at your fully burdened rate, then your standard overhead and profit markup on top. The mistake that kills margin is not the markup percentage — it is pricing extra work on the tailgate, from memory, under pressure, at a discount you would never offer on a fresh quote. Below is how to price change orders so extra work earns the same margin as the work you bid.
How to price change orders: the short version
A change order is a separate, small job that happens to occur on an existing jobsite. Treat it like one.
- Stop and document. Photo the condition, write one sentence on what changed and why.
- Pull the line items from your price book — not from your head.
- Add material at today's cost, not the cost you paid when you bid the job.
- Add labor at your burdened rate, including the disruption time the change causes.
- Apply your normal markup. Same markup as the base job, not a "since we're already here" discount.
- Get a signature before the work starts. Verbal approvals do not survive an invoice dispute.
The single highest-leverage change you can make: pre-price your 20 most common "while we're in there" tasks so a tech can produce a priced change order in under two minutes, on site, at full margin.
Why change orders quietly lose money
Change orders are not a rounding error. On most commercial work, change orders land somewhere between 5% and 10% of contract value, and the Construction Industry Institute has long pegged rework at roughly 5–9% of total project cost — a large share of which flows through change orders. If a tenth of your revenue is priced sloppily, your blended margin is being set by your worst pricing process, not your best one.
The causes are predictable. A 2025 study in Engineering, Technology & Applied Science Research analyzing 127 practitioners found that design changes accounted for 56.5% of cost overruns and 40% of delays, while planning errors accounted for 34.5% of overruns and 23.1% of delays. Translated to residential and light-commercial service work: most change orders come from conditions you could not see at quote time (a rotted joist, undersized panel, buried cleanout) plus scope you did not write down clearly enough.
Neither of those is a paperwork problem. Both are pricing problems, and they show up in three specific leaks:
- Stale material cost. You bid the job in March and discover the extra work in July. If you price the change order off the original bid sheet, you eat every increase since. See how to adjust pricing when material costs rise.
- Unburdened labor. Techs quoting "two more hours at $95" are usually quoting the billing rate they remember, not the rate that covers payroll taxes, insurance, vehicle, and non-billable time. If you have not built your labor burden rate, every change order is a guess.
- Markup confused with margin. Adding "20%" to cost gives you a 16.7% margin, not 20%. On a $400 change order that gap is small; across a year of them it is real money. Our markup vs margin explainer covers the math, and the margin and markup calculator will do it for you.
Three ways to price a change order
Pick the method that fits how well you understand the scope. Do not default to time and materials just because the change feels small.
| Method | Use it when | Watch out for |
|---|---|---|
| Flat / lump sum | Scope is clear and you have done it before — add a circuit, swap a valve, replace 8 ft of duct. | Only safe if it comes from a maintained price book. Flat-rating from memory is just guessing with confidence. |
| Unit price | You know the type of work but not the quantity — per linear foot of pipe, per fixture, per square of shingle. | Set a minimum. Ten feet of trench is not one-tenth the cost of a hundred feet. |
| Time and materials | Truly exploratory work — opening a wall, chasing an intermittent fault. | Cap it. Give the customer a not-to-exceed number and a checkpoint, or you will be arguing about hours later. |
For most field-service change orders, flat pricing from a price book wins. It is faster on site, it removes negotiation from the tech's shoulders, and it makes the number look considered rather than invented. That only works if the price book is real — see how to build a price book.
What markup should you use on change orders?
Use your standard markup. Full stop.
Contractors routinely discount change orders because they feel awkward asking for more money mid-job. That instinct is backwards. Change-order work is usually less efficient than bid work — it interrupts sequence, may require a second trip or an extra material run, and carries real schedule risk. If anything it justifies a higher markup, not a lower one.
Be aware that many written contracts cap change-order markup. Institutional and public specifications frequently limit combined overhead and profit on change-order work to around 15% for the performing trade contractor. If you sign a contract with a cap like that and your true overhead recovery needs 22%, you have agreed in advance to lose money on every change. Read the change-order clause before you sign, and price the base bid knowing what the cap will cost you. If you do not know your real number, start with calculating overhead for contractors.
Get the approval before the wrench turns
An unsigned change order is a donation. Two exceptions are worth writing into your process: immediate safety hazards and code violations, where a tech should make the site safe first and price it second.
Otherwise, the sequence is fixed: identify, document, price, present, sign, then work. Present it on the spot — same visit if possible. Approval rates fall sharply once the customer has left the emotional context of standing in front of the problem with you.
Keep the document itself short: what changed, why, the itemized price, the schedule impact, and a signature line. Note that a signed change order functions as a binding modification to the original agreement, which is a different thing from a rough estimate — the distinction is covered in quote vs estimate for contractors.
Close the loop with job costing
Change orders are the best free data your business generates. Every one of them is a note that says "we did not price this condition into the original job." If you see the same change order five times in a quarter — corroded shutoffs, undersized returns, panels with no spare breakers — that is not a change order pattern. That is a scoping gap, and the fix is to add it to your standard quote as an inspected item or an optional line.
Compare estimated versus actual on change-order work specifically, the same way you would on a full job. Our guide to job costing for contractors walks through the comparison. Contractors who do this typically find their flat change-order prices are too low on labor and roughly right on material, because the disruption time never got counted.
If you want the price book side handled — one master list of costs and prices, markup rules applied consistently, and change-order line items your techs can pull up in the field — that is what Pricebookr is built for.
FAQ
Should change orders be a separate invoice or added to the original?
Either works, but itemize them separately and reference the signed change-order number. Bundling extra work into the original line items is the fastest way to trigger a payment dispute, because the customer cannot reconcile the invoice against what they approved.
What markup should I use on a change order?
The same markup you use on your base work, at minimum. Change-order work is less efficient than planned work, so discounting it means earning below your target margin on the least efficient hours you sell. Check your contract first — many specify a maximum overhead-and-profit percentage on changes.
Can I start work before the change order is signed?
Only for immediate safety or code hazards, or if your contract contains a written change-directive clause that lets work proceed with pricing settled afterward. Absent that, unsigned work is unenforceable and you are relying on goodwill to get paid.
How do I price a change order when I don't know the full scope?
Use time and materials with a not-to-exceed cap and a defined checkpoint. Tell the customer you will stop at the cap, report what you found, and re-price the remaining work as a second change order. This is far better than guessing a flat number on unknown conditions.
How do I stop change orders from happening in the first place?
You cannot eliminate them — hidden conditions are real. You can reduce them by writing tighter exclusions into your quotes, adding a pre-work inspection line for common failure points, and reviewing your recurring change orders quarterly so repeat conditions get priced into the base bid instead.