Estimates and invoices are the two ends of the same job. Get them confused and you either fail to collect (an 'estimate' isn't a bill) or spook customers (an 'invoice' is a demand for money, not a proposal).
The short version: estimates come before the work, invoices come after. But the details matter, especially for legal enforceability.
What an estimate is. An estimate is a good-faith approximation of what a job will cost. It's not binding on either party — the customer can decline, and you can revise it if the scope turns out to be different than expected.
What an invoice is. An invoice is a formal request for payment for work already completed or goods already delivered. It creates a legal debt. If the customer doesn't pay, you can send it to collections, file in small-claims court, or (depending on your state) file a mechanics li
When to send each. Send an estimate before you commit to the job. Send an invoice after the work is done (or after milestones on longer jobs, with progress invoices).
What each document should include. The overlap is significant, but there are key differences:
Estimate → invoice: the smooth handoff. The best workflow: send an estimate, get it approved (ideally with a digital signature), do the work, then convert the estimate to an invoice with any scope changes noted as change orders. This preserves the audit trail — the customer can see exactly what they
Frequently asked questions
Can an estimate be legally binding?
In most cases, no — it's an approximation, not a contract. A signed quote or a signed contract can be binding. If you want a binding number, use the word 'quote' and get it signed.
Can I charge more than the estimate?
If the scope changed, yes — but document it with a change order before doing the extra work. Charging more than an estimate without notice is the fastest way to end up in small-claims court.
Do I have to send an estimate first?
Not legally. For small, well-known jobs (a $75 oil change, a standard haircut) you can skip straight to the invoice. For anything with variable scope, an estimate protects both sides.
