An estimate is what you expect a job to cost, sent before the work is agreed. An invoice is a request to be paid for work already done. Same layout, opposite direction: one asks for a decision, the other asks for money.
What actually changes between them
Most of the document is the same — your details, their details, line items, totals. The differences are small and all of them matter.
| Estimate | Invoice | |
|---|---|---|
| Sent | Before the work is agreed | After the work is done |
| Asks for | A yes or a no | Payment |
| Second date | An expiry date — how long the price holds | A due date — when payment is expected |
| Numbering | Its own sequence, so estimates that go nowhere leave no gaps | Its own sequence, unbroken and unique |
| Deposits | Stated as a condition of booking | Shown as already received, reducing the balance |
| Tone of the amounts | A price you are offering | A figure that has already been earned |
Estimate, quote, or proposal?
These words get used interchangeably and it causes more confusion than the invoice question does. In everyday trade usage:
- An estimate is a considered guess. The final figure may move if the job turns out differently.
- A quote is usually understood as a fixed price for a defined scope.
- A proposal is a quote with the reasoning attached — common in consulting, rare in the trades.
Two things are worth being clear about. The word on the document is not what makes a price binding; the agreement you reach with your customer is. And whether a given price commits you legally depends on that agreement and on the law where you are — which is exactly why the document should say, in plain words, whether the figure is fixed or indicative.
The workflow most service businesses end up with
- Look at the job. On site, on a call, or from photos.
- Send the estimate, with a scope and an expiry date. Two weeks is a common window and protects you from someone accepting a six-month-old price after your costs have moved.
- Get a yes in writing. A reply to the message is enough for most small jobs. For anything with a deposit, get the deposit.
- Do the work, and note anything that changed as it happens rather than reconstructing it later.
- Invoice against the estimate. Same line items, in the same order, so the customer can hold the two documents side by side. Anything added goes on as its own line, described as agreed on the day.
Example
The same job, twice
An estimate for a fence replacement, then the invoice that followed it. Note that the invoice keeps the estimate's line order and adds the extra work as a separate, dated line.
Estimate EST-0018 · valid until 30 June 2026
- Remove and dispose of existing fence18 linear metres
- $340.00
- Supply and install closeboard fencing18 linear metres @ $58
- $1,044.00
- Concrete post fixing10 posts
- $160.00
- Estimated total
- $1,544.00
Prices held for 30 days. A 25% deposit confirms the booking. If a post base needs excavating below 600mm, that will be quoted separately before any additional work starts.
Invoice INV-0091 · due 21 July 2026
- Remove and dispose of existing fence18 linear metres
- $340.00
- Supply and install closeboard fencing18 linear metres @ $58
- $1,044.00
- Concrete post fixing10 posts
- $160.00
- Additional excavation, posts 4 and 5Agreed on site 8 July, 2 hrs @ $45
- $90.00
- Total
- $1,634.00
- Deposit received 22 June
- −$386.00
- Balance due
- $1,248.00
When the job changes
This is where estimates earn their keep and where they most often go wrong. If the work grows, the moment to say so is when it grows — not on the invoice. A message on the day (“the post bases need digging deeper, that’s another two hours at $45, happy to go ahead?”) turns a surprise into an agreement, and the invoice line then just records something the customer already knows.
On larger jobs this is formalised as a change order, which is worth doing properly — the contractor page covers how that flows onto the final invoice. On small jobs, a text message is genuinely enough, as long as it exists.
Do you need both?
It depends entirely on whether your customers know the price before you start.
- Fixed, published prices — a tutor at an hourly rate, a cleaner on a standing weekly job. Invoice only. An estimate adds a step that answers nothing.
- Variable work you price after looking — repairs, garden work, decorating, most handyman jobs. Both, always.
- Booked work with a deposit — weddings, events, multi-day projects. Both, and the estimate is doing the heavier job of the two.
Once the job is done, the mechanics of the bill itself are covered in how to invoice for services and what to include on an invoice.
