How much deposit should a tradesperson ask for?
There is no legal figure and no industry rate. The defensible answer is what you have to pay out before you start — the materials and any non-returnable order — not a percentage of your profit. On a small job, ask for nothing. On a long one, forget the deposit and stage the payments against milestones instead. Whatever you settle on, it has to be on the quote before they accept it: a deposit mentioned for the first time afterwards is a change to the deal, and they can say no.
What a deposit is actually for
A deposit is not a fee and it is not profit taken early. It does two jobs. It covers money you have to spend before you earn anything — the boiler, the units, the tiles, a special order that cannot go back — so that a job going quiet does not leave you out of pocket on somebody else's materials. And it is a small commitment that tells you the customer means it, which matters when accepting means you turn other work away for that week.
Being clear about which of those you are asking for changes the conversation. “A deposit of £1,000 covers the boiler, which I order on Monday” is a sentence a customer can agree with. “I take 50% up front” invites them to wonder why.
How much is reasonable?
People will tell you a third, or a half, or nothing. Those are conventions rather than rules, and they are a poor guide because they scale with the price of the job rather than with your exposure on it. A £4,000 job that is mostly your labour needs a much smaller deposit than a £4,000 job that is mostly a unit you have to buy on Monday.
So work it out rather than reaching for a fraction. Add up what leaves your account before the first day's work: materials you must order, hire, anything non-returnable. That number, rounded sensibly, is a deposit you can explain and defend. On a boiler swap it is roughly the boiler. On a rewire where you draw materials as you go, it may be very little.
Two sanity checks. If the deposit is most of the job's value, a customer is right to hesitate, and you should look at staging instead. And if the deposit is more than the materials, you are asking to be paid for work you have not done, which is what makes customers nervous about deposits in the first place.
On a longer job, stage the payments instead
Past a week or so of work, a single deposit is the wrong instrument. Stage the payments against milestones the customer can actually see: first fix complete, plastering done, boiler commissioned, final snagging signed off. Each stage is an amount and a trigger, both written on the quote.
This protects both sides, which is why it is easier to sell than a big number up front. You are never more than one stage out of pocket. They are never paying far ahead of what has been built. And the milestones give you a natural moment to raise anything that has changed, rather than saving it all for an invoice at the end.
Put it on the quote, not in a later phone call
The deposit is part of what the customer is agreeing to, so it belongs on the document they accept, in the payment terms alongside when the balance falls due. A deposit introduced after acceptance is a change to an agreed contract — as the guide on whether a quote is legally binding sets out, they are entitled to decline it, and you are left choosing between doing the job on the original terms and starting an argument.
One line does it: “Deposit of £1,000 on acceptance, covering the boiler. Balance due on commissioning.” Name the amount, what it covers, and when the rest is due. These are the same sentences on nearly every job you quote, which is why they are worth writing once and printing on everything rather than retyping and half-remembering.
When not to ask for one
On a small job, a deposit costs more than it is worth. Asking somebody to transfer £40 before you come and fix a tap buys you almost no protection and spends goodwill you would rather keep — and the admin of chasing it is worth more than the money. The same goes for a repeat customer who has always paid, and for emergency callouts where the value is in turning up fast. Save deposits for jobs where you are genuinely exposed.
What happens if they cancel?
A deposit is not automatically yours to keep. Where the work was agreed in the customer's home — most trade work — the consumer normally has a 14-day cancellation window, and cancelling inside it generally means the deposit goes back. That is one of the reasons the legally-binding guide makes such a point of getting the customer's written request if they want you to start before the window closes: without it, you can be doing work you may not be paid for.
Where you have already spent the deposit on something non-returnable, the position depends on what was agreed and when, and it is genuinely fact-specific. Citizens Advice is the free starting point, and this guide is general information rather than legal advice.
Make it one less thing to remember
Deposits and payment terms are the most repetitive part of a quote and the part most often left off. In Speak to Quote you write your terms once in Business details and they print on every quote and estimate you build after that, in the footer where a customer looks for them — so the deposit line is on the document without you thinking about it, and the same wording goes out every time. The builder page and the plumbing and heating page show where it lands on a finished document.