What is a change order in construction?

A change order is a short numbered document that amends a job you already quoted. It states what changed and why, what work is being added or removed, the new contract total, what it does to the schedule, and carries signatures from both the contractor and the customer. It does not replace the original estimate and it is not a second job — it rides along with the first one and rolls into the same final invoice.

What has to be on a change order?

Seven things: its own sequential number plus the number of the job it amends; the date it was written; one plain sentence saying what changed and why; the work added, priced line by line; any work removed, shown as a credit; the original contract amount, this change, and the new total stacked together; and the schedule impact with a signature line for both parties.

Does the customer have to sign a change order before the work starts?

That is the rule that makes it worth writing. A change order signed after the work is done is an invoice with extra steps — it has no leverage, because you are asking rather than agreeing. Get the signature before anyone touches the change. Requirements for enforceable contract amendments vary by state and by contract, so check your state.

Do I bill a change order separately from the original invoice?

No. One job, one final invoice. The original scope and every approved change order land on the same bill, so the customer sees one number to pay and one balance to clear. If the job runs long enough to need money partway through, take a progress payment against the same job rather than issuing a separate invoice for the change.

How should I price change-order work?

Price it the way you would price the job if it walked in on its own: your labor rate, your materials markup, your normal minimum. Do not discount change work because you feel the estimate was wrong — the conditions changed, not the estimate. Include second-order costs too: another trip, a permit amendment, a part you cannot return, a day of schedule you cannot resell.

How to Write a Change Order (With a Template)

The wall comes off, and what's behind it isn't what you quoted. Now you have a choice: eat it, argue about it later, or write it down before you touch it. A change order is the third option — a short, numbered document that says what changed, what it costs, what it does to the schedule, and that the customer agreed to all three before the work happened.

It isn't paperwork for its own sake. It's the difference between "we discussed that" and a signature with a date on it.

What a change order actually is

A change order amends a job you already quoted. It doesn't replace the original estimate and it isn't a second job — it's an addendum that rides along with the first one and rolls into the same final invoice. Three things make it a change order rather than a note: it's numbered, it's priced, and it's signed before the work starts.

Why "sure, I'll add it" costs you money

Verbal changes fail in one predictable way. You remember a number, the customer remembers a smaller one or no number at all, and the disagreement surfaces at the worst possible moment: when you hand over the final bill and they're deciding whether to pay it. Nobody is lying. Two people just remembered a driveway conversation differently, three weeks apart.

The second cost is quieter. Scope creep that never gets written down never gets priced, and a job that was making 30% ends up making 12% because of four small "while you're here" additions nobody billed for. Writing each one down forces you to price it, which is the whole point.

The seven things a change order has to say

Its own number, and the number of the job it amends. CO-2026-001 against Q-2026-047. Sequential, never reused.
The date. The day it's written, not the day the work happens.
What changed and why, in one plain sentence. "Feeder is aluminium, not copper as assumed." Not "additional work as discussed."
What's being added, priced line by line the way you'd price anything else.
What's being removed, if anything, as a credit. A change order that only ever adds looks like a shakedown; one that credits what you're no longer doing looks like arithmetic.
The new contract total. Original, this change, new total. Three numbers, stacked, so nobody has to add them up.
What it does to the schedule, and a signature line for both of you.

The one rule that matters: the customer signs before the work on the change starts. A change order signed afterwards is an invoice with extra steps — it has no leverage, because the work is already done and you're asking rather than agreeing.

A change order template you can copy

Plain text, on purpose — select it, paste it into whatever you already use, and fill in the blanks. Nothing here is trade-specific.

CHANGE ORDER

Change Order No.:  CO-2026-001
Date:              September 11, 2026
Original job:      Q-2026-047  (Panel upgrade, 14 Oak St)

Contractor
  Your Business Name
  Address / phone / email
  License #:

Customer
  Name
  Job address (if different from billing)

WHAT IS CHANGING AND WHY
  Opened the wall at the panel and found the feeder is
  aluminium, not copper as assumed at the walkthrough.
  Code requires it replaced to complete the upgrade.

WORK ADDED
  1. Replace 3/0 aluminium feeder, panel to meter ...  $ 640.00
  2. Additional permit amendment ......................  $  85.00

WORK REMOVED (credit)
  1. None ............................................  $   0.00

PRICE
  Original contract ..................................  $2,450.00
  This change order ..................................  $  725.00
  New contract total .................................  $3,175.00

SCHEDULE
  Adds 1 working day. New completion: September 16, 2026.

TERMS
  Billed with the final invoice. Terms unchanged: Net 15.
  Work on this change order does not start until signed.

APPROVED

  Customer _______________________   Date ____________

  Contractor _____________________   Date ____________

Pricing the change

Price it the way you'd price the job if it walked in on its own: your labor rate, your materials markup, your normal minimum. The most common mistake is quietly discounting change work because you feel bad the estimate was wrong. The estimate wasn't wrong — the conditions changed. If you've built a flat-rate price book, most change orders are one or two templates out of it, priced in under a minute.

Don't forget the second-order costs. A change can mean another trip, another permit amendment, restocking a part you can't return, or a day of schedule you can't sell to anyone else. Those are real; put them on the line items rather than absorbing them.

What happens at invoice time

One job, one final invoice. The original scope and every approved change order land on the same bill, so the customer sees one number to pay and one balance to clear. If the job ran long enough to need money partway through, that's a progress payment against the same job, not a separate invoice — see payment terms for contractors for how the due date works, and receipt vs invoice for what to send once each payment lands.

In QuoteIron: a change order is its own numbered document tied to the job it amends. It gets sent for approval like any quote, the customer signs it on their phone, and once it's approved the lines roll into the parent job's final invoice — you never bill a change order on its own. It's included in Pro rather than being a higher-tier feature; the QuoteIron vs Joist comparison shows where it sits on other apps' price lists.

Trades where this bites hardest

Anything that opens a wall, a roof or a slab. Electrical and plumbing retrofit work in older houses is the classic case — what's behind the drywall decides the price. Roofing runs on deck rot found after tear-off. HVAC changeouts turn up ductwork nobody costed. If your trade is on that list, a change order isn't occasional paperwork; it's part of the job.

More on how QuoteIron handles quoting, approvals and invoicing end to end is in the FAQ, and if you're weighing tools, the Housecall Pro alternative page compares what's included against what's a tier upgrade.

General information for tradesmen, not legal advice. Contract terms, notice requirements and what counts as an enforceable amendment vary — check your state and your own contract before you rely on any template, including this one.