James
Founder, PayReady
James spent 20 years developing software and apps for Johnson and Johnson, Disney, and Eli Lilly before building PayReady for the tradesmen he saw drowning in paperwork.
“Quote”, “estimate”, “invoice” - these three words are used almost interchangeably in conversation, but they mean very different things in law and in practice. Mixing them up can leave you unable to chase a debt or exposed to a price dispute.
What is a quote?
A quote (also called a quotation) is a formal offer to carry out a specific job for a stated price. When a customer accepts your quote - verbally or in writing - it becomes a legally binding contract. You cannot increase the price after acceptance without the customer's agreement, even if the job costs you more than expected.
A quote should clearly state:
- Exactly what work is included
- What is explicitly excluded
- The fixed price
- How long the quote is valid
- Payment terms
What is an estimate?
An estimate is an approximation of what a job might cost. It is not legally binding. If the final cost comes in higher than estimated, you are generally entitled to charge the higher amount - as long as the difference is reasonable and the customer understood it was an estimate.
In practice, most customers treat estimates and quotes as the same thing. To protect yourself, always make clear in writing whether you are providing a fixed price (quote) or an approximation (estimate). When in doubt, call it a quote and build in a realistic contingency for unknowns.
Quote vs estimate - when to use which
| Use a quote when | Use an estimate when |
|---|---|
| You have seen the full scope of the job | The scope depends on what is found under floors or inside walls |
| Material quantities are predictable | Material quantities cannot be known until work opens up |
| The customer wants a fixed price | The customer understands prices may change with conditions |
| You can build in a contingency for unknowns | The risk of major unknowns makes a fixed price unrealistic |
What is an invoice?
An invoice is a request for payment for work already completed (or for a stage that has been reached). It is issued after the job, not before. An invoice is not an offer - it is a demand for money owed.
An invoice should match the accepted quote. If additional work was done beyond the original scope, it should be itemised separately - and ideally agreed in writing with the customer before you did it.
The document sequence on a trade job
A typical trade job follows this sequence:
- Quote - you send a fixed-price offer describing the work
- Acceptance - the customer says yes (verbal or written)
- Work - you complete the job
- Invoice - you send a payment request matching the accepted quote
- Payment - the customer pays within the agreed terms
For larger jobs with stage payments:
- Quote with a payment schedule (deposit + balance, or milestones)
- Deposit invoice (before work starts)
- Progress invoice (at an agreed milestone)
- Final invoice (on completion)
Can you change the price after a quote is accepted?
Generally no. A quote is a binding offer once accepted. Exceptions:
- The customer requests changes to the agreed scope - that is a new quote or a variation agreement
- The quote includes a contingency clause for unforeseen conditions that actually materialise
- Material prices change significantly after acceptance (a validity period protects against this)
Any price change after acceptance should be agreed in writing before the additional work proceeds. A WhatsApp message saying “Happy to add the extra socket for £150 inc VAT, shall I proceed?” and a reply of “yes go ahead” is enforceable and protects both parties.
What is a pro-forma invoice?
A pro-forma invoice looks like an invoice but is not a demand for payment. It tells the customer what the invoice will look like before the work is done or goods are delivered. It is commonly used for deposit requests or advance payment arrangements.
For most sole trader tradesmen, a clear quote with payment terms is sufficient. Pro-forma invoices are more common in commercial supply relationships.
How PayReady handles quotes and invoices
PayReady manages both documents. You create a quote from a plain English job description - PayReady AI structures it with the correct VAT rate and you send it via WhatsApp or email. When the job is complete, you convert it to an invoice in one tap. The figures carry across automatically. You do not re-enter anything.
Invoice generator Free tool
Once the job's done, turn it into a proper invoice PDF in seconds - logo, VAT, and line items included.
Download a free quote or invoice template for your trade, or get early access to PayReady - it's free.
For the full guide on writing professional quotes, see how to write a quote that wins jobs.
Sources
- Contracts and your rights as a consumer - citizensinformation.ie
- Quotes and estimates (consumer guidance) - GOV.UK
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