Invoice vs Quote: What's the Difference for Tradies?

Tradies often use the words “invoice” and “quote” interchangeably. They’re not the same thing. Using the wrong one at the wrong time can mean unpaid work, price disputes, or tax problems.

Here’s what each one is, when to use it, and how to move from one to the other.

What is a quote?

A quote is a written offer to do specific work at a specific price. It’s sent before the work starts. When the customer accepts it, both parties have agreed to the scope and price.

A quote is a commitment — you’re saying “I will do this work for this amount”. The customer is saying “yes, I want that work done at that price.”

Key features of a quote:

Sent before work begins
Lists the work to be done with estimated prices
Has a validity period (e.g. “Valid for 30 days”)
Can be approved or declined by the customer
Not a demand for payment

What is an invoice?

An invoice is a request for payment for work already completed (or in progress). It’s sent after the work is done.

An invoice is a legal document — in most countries, it’s the official record of a transaction for tax purposes.

Key features of an invoice:

Sent after work is completed
Lists the work done and the final prices
Includes tax (GST, VAT, HST, or sales tax)
States a payment due date
Is a formal demand for payment

Quote vs invoice: side-by-side comparison

	Quote	Invoice
When sent	Before work starts	After work is done
Purpose	Get approval to proceed	Request payment
Legal status	Offer (not yet binding)	Legal payment demand
Includes tax	Sometimes	Always
Payment due	N/A	Yes — states due date
Can be declined	Yes	N/A

Do you always need a quote?

No. For small, straightforward jobs you both know the price for — an oil change, a standard callout, an hourly rate — you can go straight to an invoice.

Quotes are important when:

The scope of work needs to be agreed upfront
The price varies depending on what you find (e.g. “we’ll need to open it up to see the extent of the damage”)
The customer needs to approve a cost before you start
You’re competing for the job against other tradies
The job is large enough that a dispute about price would be painful

What is an estimate?

An estimate is similar to a quote but less binding. An estimate says “the work will cost approximately $X” — it’s your best guess, not a firm price. Quotes are fixed; estimates can vary.

In everyday tradie language, “quote” and “estimate” are often used interchangeably. For legal purposes, if you want a fixed price to be agreed upfront, call it a quote. If you’re not sure of the final cost yet, call it an estimate and make that clear in writing.

The quote-to-invoice workflow

The most efficient way to work:

Inspect the job → send a quote with detailed line items
Customer approves → you’re authorised to proceed at the agreed price
Complete the work → create the invoice from the approved quote
Send the invoice → customer pays

When your quote and invoice are linked, there’s no dispute about price. The invoice matches what was approved. No surprises.

In Spanner, converting an approved quote to an invoice takes one tap — all line items, customer details, and pricing carry over automatically.

Common mistakes tradies make

Starting work without a quote: If there’s no written agreement, the customer can dispute the price after the fact. Always get it in writing before starting significant work.

Quoting too vaguely: “Car service — $300” tells the customer nothing. “Engine oil + filter change, spark plug replacement, brake fluid top-up — $300” prevents disputes.

Not converting quotes to invoices: Starting fresh each time you move from quote to invoice wastes time and introduces errors. Keep them linked.

Using “invoice” for a pre-work document: Sending an “invoice” before work starts is technically incorrect and can confuse customers. Send a quote, then invoice after.

GST, VAT, and tax on quotes vs invoices

Quotes often show tax (to give the customer the full picture) but this isn’t always legally required.

Invoices must show tax separately in most countries:

Australia: if you’re GST-registered, the GST amount must be clearly shown on tax invoices over $82.50
UK: VAT-registered businesses must show the VAT amount and their VAT number on every invoice
Canada: GST/HST-registered businesses must show the tax amount and their Business Number
New Zealand: GST-registered businesses must show GST separately on tax invoices
USA: if you’re charging sales tax, it must be shown as a separate line item

Frequently asked questions

Can a quote become an invoice? Yes — and that’s exactly how it should work. When the customer approves the quote and the work is done, convert it to an invoice. In Spanner this is one tap.

Does a quote have to include GST or VAT? Not legally required in most countries, but best practice is to show the tax-inclusive total so the customer knows the full price.

What if my final price differs from the quote? If the scope of work changed, you need a variation — a written update to the original quote that the customer approves before you proceed. Invoicing for more than the quoted amount without agreement can lead to disputes.

How long should a quote be valid for? 14–30 days is standard for most trade work. For jobs dependent on material prices (e.g. large builds), shorter validity periods (7 days) are common.

Send quotes with online approval links or create and share invoices in seconds — both features are built into Spanner.