Contractor paperwork
Change order vs. estimate vs. invoice
An estimate explains the expected job before agreement. A change order documents an approved change after the original scope is established. An invoice requests payment for work and charges that are due.
The short version
| Document | Main purpose | Typical timing | Customer action |
|---|---|---|---|
| Estimate or proposal | Describe and price the original job | Before the original agreement | Review and accept the proposed work |
| Change order | Modify the agreed scope or price | After agreement, before changed work | Approve the specific change |
| Invoice | Request payment | At a billing milestone or completion | Pay the amount due |
What an estimate does
An estimate or proposal describes the anticipated original scope and price. Depending on its wording and acceptance, it may be an early planning document or part of the agreement. It is not the best place to quietly add new work after the customer has already approved the original job.
What a change order does
A change order connects the new decision to the original job. It should identify what is added, removed, or revised; why the change is needed; how the contract price changes; and whether other terms are affected. The customer approves that change before the contractor relies on it.
For example, an estimate may include replacing a bathtub. If demolition reveals damaged subfloor that was not included, a change order can document the repair scope and added price before the repair begins.
What an invoice does
An invoice is the payment request. It can reference the original agreement and approved change order numbers, but sending an invoice after performing unapproved extra work does not create the same clear approval record. Keep approval and billing connected, but do not confuse their purposes.
A clean contractor workflow
- Send the estimate or proposal for the original job.
- Record the accepted agreement and original job number.
- When the scope changes, create a change order tied to that job number.
- Collect written approval before starting the changed work.
- Complete the work and retain the signed change order.
- Reference the approved change order on the invoice.
Keep the approval side of the job documented
JustSignOff supports the original estimate or work proposal, later change orders, and service authorizations. It keeps the customer-approved record while your accounting system continues to handle invoices and payments.