How to write a change order (with template)

Every job changes. The client picks a different tile, the wall you opened has rot behind it, or they ask you to “just quickly” do the closet as well. None of that is a problem. The problem is doing the extra work on a handshake and then putting a number on the invoice the client has never seen.

A change order fixes that. It is a one-page agreement that says what changed, what it costs and how it affects the schedule — approved by the client before the work starts.

When do you need a change order?

• The client asks for work that was not in the estimate.
• You find something that has to be dealt with before you can continue, such as rot, wiring that is not up to code or a hidden leak.
• The client changes a material, fixture or finish after you have priced it.
• Work is removed from the job, which should lower the price.
• The schedule changes in a way that costs you, such as a delay the client causes.

A useful rule: if the change would surprise the client when they read the invoice, it needs a change order.

What should a change order include?

1. A change order number, such as CO-1, CO-2, and the date.
2. The original estimate or contract number it changes.
3. The client’s name and the job address.
4. A plain description of the change: what is being added, removed or swapped, and why.
5. The cost: labour, materials and tax for the change, itemised like an estimate.
6. The effect on the schedule, even if it is “no change”.
7. The new job total, and the client’s approval with a date.

What does a change order look like?

Copy this and change the details. It works as a document, an email or a text.

Change order CO-2 · October 14, 2026 · Changes estimate EST-118, 42 Maple Street. Change: add an exhaust fan to the main bathroom, including ducting to the exterior wall. Reason: requested by the client during rough-in. Cost: labour $320.00, materials $185.00, tax (13% HST) $65.65, total $570.65. Schedule: adds half a day; completion moves from October 20 to October 21. Original job total $8,420.00 + previous changes $310.75 + this change $570.65 = new job total $9,301.40. Approved by: ________ Date: ________

Why get approval before you start the extra work?

The order matters. Price the change, send it, get a yes in writing, then do the work. Once the extra work is finished you have lost your leverage: the client can say they never agreed to the price, and you are negotiating after the fact.

On site, the quickest way is to write the change order on your phone and have the client sign it there and then. If they are not around, send it and wait for a written reply before you continue with the changed work. A text that says “Yes, go ahead with CO-2” is far better than a verbal OK.

Rules for written change orders vary. California, for example, requires change orders on home improvement contracts to be in writing and signed. Check what applies where you work.

How do you price a change?

Price a change order the same way you priced the job: your hourly rate times the hours, materials with your usual markup, plus tax. Two things are easy to miss:

• The knock-on time. A change in the middle of a job often means another trip for materials, rework of something already finished, or waiting on a delivery. Count it.
• Credits. If the change removes work or materials, show the credit as a negative line. Clients notice when changes only ever go up.

How do you put change orders on the invoice?

The final invoice should line up with the paperwork the client already has. Keep the original scope as its own lines, then add each change order labelled with its number.