If you're a tradesman in the UK, you've probably used the words "quote" and "estimate" interchangeably. Most customers do too. But legally, the difference between a quote and an estimate is significant — and using the wrong one could cost you money or even land you in a legal dispute.

The short answer: a quote is a fixed, legally binding price. An estimate is an approximate price that can go up or down. But there's much more to it than that — especially when it comes to UK consumer law, winning jobs, and protecting your business.

This guide covers the difference between a quotation and an estimate with real examples, a comparison table, and advice on when to use each.

What Is a Quote?

A quote (also called a quotation) is a fixed price for a specific piece of work. Once a customer accepts your quote, it becomes a legally binding agreement under UK contract law. You cannot charge more than the quoted amount unless the customer agrees to additional work outside the original scope.

Key characteristics of a quote:

  • Fixed price — you must honour it
  • Legally binding once accepted
  • Usually has a validity period (e.g., 14 or 30 days)
  • Should include a detailed breakdown of what's included
  • Must clearly state what is not included

Example of a Quote

A plumber visits a customer's home, inspects the existing boiler, and provides a written quote:

Boiler replacement (Vaillant ecoTEC Plus 832): £2,400 including parts, labour, removal of old boiler, and Gas Safe certificate. Excludes any additional pipework modifications. Valid for 30 days.

If the customer accepts this quote, the plumber must do the work for £2,400 — even if it takes longer than expected.

What Is an Estimate?

An estimate is an approximate price based on your best professional judgement. It gives the customer a ballpark figure but is not legally binding. The final cost can go up or down depending on what you find during the work.

Key characteristics of an estimate:

  • Approximate price — can change
  • Not legally binding
  • Used when exact costs are uncertain
  • Should still be as accurate and reasonable as possible
  • Must not be deliberately misleading (this could be considered unfair trading under UK consumer law)

Example of an Estimate

An electrician is asked to find and fix an intermittent tripping issue:

Estimated cost: £150-£300 depending on the fault. This is an estimate only — the final cost may vary once the cause is identified. Diagnostic rate: £65/hour.

The electrician doesn't know exactly what's wrong until they start investigating, so a fixed quote wouldn't be appropriate.

Quick Comparison

Quote Estimate
Price Fixed Approximate
Legally binding? Yes (once accepted) No
Can price change? No (unless scope changes) Yes
Best for Clear, defined jobs Uncertain or complex jobs
Customer confidence High Lower

When to Use a Quote

Use a quote when:

  • You can clearly define the scope of work
  • You've done a site visit and know what's involved
  • The job is straightforward (e.g., fitting a new boiler, rewiring a room)
  • Material costs are stable and predictable

Pro Tip: Customers prefer quotes because they know exactly what they'll pay. If you can offer a fixed quote, you're more likely to win the job over a competitor who only gives an estimate.

When to Use an Estimate

Use an estimate when:

  • You can't see the full extent of the work (e.g., hidden damp, underground pipes)
  • The job involves unknowns that could affect cost
  • Material prices are volatile
  • The customer hasn't finalised exactly what they want

Protecting Yourself

Whichever you use, protect yourself with these practices:

  1. Always put it in writing — verbal quotes can lead to disputes
  2. Be specific about what's included — and what isn't
  3. Include a validity period — material prices change
  4. Add a variation clause — "Any additional work not specified in this quote will be charged at £X per hour"
  5. Get acceptance in writing — an email reply saying "go ahead" is enough

Quote vs Estimate: Real Examples by Trade

Here's when to use each, depending on your trade:

Trade Use a Quote Use an Estimate
Plumber Boiler install, tap replacement, radiator fitting Leak investigation, drain unblocking, hidden pipework
Electrician Consumer unit upgrade, socket addition, rewire Fault finding, intermittent tripping, fire damage repair
Builder Extension (after architect plans), kitchen fit Structural repairs, subsidence work, renovation of old properties
Painter Full room repaint, exterior woodwork Damp-damaged walls (extent unknown), stripping old wallpaper
Roofer Replacing tiles, new flat roof Leak investigation, storm damage (extent unknown)

What About a Tender?

You might also hear the term tender, especially on larger commercial or public sector jobs. A tender is a formal process where multiple contractors submit sealed bids for a project. It's essentially a competitive quote — the client sets the scope and contractors compete on price and quality.

For most self-employed tradesmen doing domestic work, you won't need to worry about tenders. Quotes and estimates are what you'll use day-to-day.

UK Legal Position on Quotes and Estimates

Under UK law:

  • A quote that has been accepted forms a binding contract. You must complete the work for the agreed price.
  • An estimate is not binding, but the final price must still be reasonable. Under the Consumer Rights Act 2015, if no price is agreed, the customer must pay a "reasonable charge" for the work done.
  • Deliberately giving a low estimate to win work and then charging significantly more could be considered an unfair commercial practice under the Consumer Protection from Unfair Trading Regulations 2008.
  • If the final cost is going to exceed your estimate by more than 10-15%, it's good practice to contact the customer before continuing and get their agreement to the higher cost.

Frequently Asked Questions

Is a quote legally binding in the UK?

Yes. Once a customer accepts your quote, it forms a legally binding contract. You must complete the described work for the agreed price. If the job changes or additional work is needed, you should issue a new quote or variation for the extra work.

Can I change a quote after the customer accepts it?

Not without the customer's agreement. If you discover something unexpected (like hidden asbestos during a rewire), you should stop, explain the situation, and provide a revised quote or estimate for the additional work. The customer can then decide whether to proceed.

What if my estimate is way off?

If the final cost is going to be significantly higher than your estimate, contact the customer as soon as you know. Explain why costs have increased and get their agreement before continuing. A good rule of thumb: if it's going to exceed 15% of the estimate, call the customer.

Should I always give a quote instead of an estimate?

Customers strongly prefer quotes because they know exactly what they'll pay. You're more likely to win work with a fixed quote. However, never give a fixed quote for work where you genuinely can't predict the cost — you'll end up losing money. Use estimates for uncertain situations and quotes for everything else.

The Bottom Line

The difference between a quote and an estimate comes down to certainty. Use quotes whenever you can — they give customers confidence and help you win more jobs. Save estimates for genuinely uncertain situations where fixing a price would be a gamble. And whatever you send, always put it in writing with a clear scope of work.

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