How to tell a customer the job will cost more
The script for the moment you have to break the news that the price has gone up - how to tell which of the three causes you are in, when to make the call, what to say in person and in writing, and the one habit that stops every mid-job price conversation turning into an argument.
You have lifted the floor and the joists are gone. You have opened the wall and the cable is shared with next door. You have priced the kitchen and the customer has just said the words "while you are at it, could we also..." Whichever version you are in, the next conversation is the one most tradespeople dread, and the one most likely to end in either a discount you cannot afford, a hit you absorb because you did not want the argument, or a customer relationship that never quite recovers.
The conversation is hard for the same reason every time. You feel like you are the one delivering bad news, even when the reason for the extra cost has nothing to do with you. The customer hears "more money" and reads it as "you got this wrong". And by the time you raise it, the work is already in motion, so the customer feels cornered into saying yes. Get any one of those three things wrong and the conversation goes sideways.
The script below is the fix: how to work out which of the three causes of "the job will cost more" you are actually in, the 24-hour rule that decides when to make the call, the exact wording for the moment, and the one-message follow-up that gets you a written approval before the kettle has finished boiling.
Work out which of the three causes you are in before you say anything
There are only three reasons a job costs more than the quote. The conversation goes wrong when you treat them all the same. Sixty seconds of thinking about which one you are in before you pick up the phone changes the entire tone of the next exchange.
- Cause 1 - genuine discovery. You lifted the floor and found rot. You opened the wall and found asbestos. You started the dig and hit a service. The work needed has changed because of something nobody could have seen from outside the wall. Your tone here is calm and factual - this is news, not an apology, and the customer is your ally because the cost is going on the house, not your invoice. Take photos before you cover anything back up.
- Cause 2 - customer-requested extras. "While you are at it..." is the most expensive sentence in domestic trade work. The customer has asked for something that was not in the quote, and they almost always think they are asking a small favour. Your tone here is friendly but specific - "happy to do that, here is what it adds" - and the price needs to be on a separate line, not folded into the original total at the end.
- Cause 3 - you underpriced. The hardest one to raise because the reason is your own miscalculation. The honest version is the only version that works long-term: "I priced this at half a day and it is going to be a full day - I want to flag it now rather than at the end." Most customers respect that. Some will ask you to absorb part of it, which is a fair conversation. Hiding it and slipping it onto the final invoice is how you lose the customer and the referral.
The 24-hour rule - the longer you leave it, the worse the conversation
The cost of telling a customer the price has gone up doubles every day you wait. On day one of discovery it is a calm five-minute call. By day three it is a defensive conversation. By the end of the job it is an argument the customer feels ambushed by, because they have been signing off on work they assumed was within budget.
- Make the call the same day you discover the issue. Do not wait until end-of-day to write the perfect message - a "quick heads-up, will send the detail by the end of the day" text in the moment is better than a polished email twelve hours later.
- For customer-requested extras, raise the cost before you start the extra work. The line "happy to do that, it adds about £X, want me to crack on?" gets a yes 90% of the time. The same conversation after the work is done gets you "I did not think it would be that much".
- For your own miscalculation, raise it as soon as you know - usually by the end of the first day. The longer you carry it, the more invested you both are in pretending the price is fine, and the more painful the eventual reveal becomes.
What to say in person, on the phone, and by message
The wording for the in-the-moment conversation depends on which cause you are in, but the structure is the same: state the news, show the evidence, give the new number, ask for a clear yes or no, and follow up in writing within the hour.
- Discovery, in person - "Right, come and have a look at this. The joists under the bay window have got dry rot - here, see where the screwdriver goes in. We have got to replace these three before we can put the floor back down. It is about an extra day and £420 in timber and treatment. Are you happy for me to crack on with that, or do you want to think about it?"
- Discovery, by message - "Hi [name], quick update from site - lifted the floor in the bay window and found dry rot in three joists, will text you a photo in a sec. They need replacing before the new floor goes down. Adds about a day on site and around £420 for the timber and treatment, so the total comes up from £4,200 to roughly £4,800. Happy to crack on if you give me the go-ahead, but want to flag it now rather than just bill it. Let me know."
- Extras, in person - "Yeah, happy to add the second downlight to the dining side. Adds about £85 with the fitting. Want me to put it on the same invoice, or treat it as a separate line?"
- Your own miscalculation, by message - "Hi [name], wanted to flag something before the end of the job rather than at the invoice. The plastering side has run to a full day rather than the half I priced for - the walls needed more prep than I had allowed for. I am going to split the difference and ask for an extra £140 on the labour line. Would rather raise it now than have it land as a surprise at the end. Let me know if that works."
- Across all three versions, do not bury the number. The customer is going to fixate on the new total whether you mention it early or late, so put it in the second sentence and let them sit with it while you explain the reason.
Put it in writing within the hour - the one habit that stops the argument at the end of the job
A verbal yes on a driveway is worth nothing six weeks later when the final invoice lands. The customer remembers a smaller number; you remember the agreed extra. Both of you are right about what you remember; neither of you can prove it. The fix is a single message sent the same day, captured against the job in your records, with a clear line item and a clear yes-or-no ask.
- Format: one short paragraph stating what changed, why it changed, what it costs, and what the new total is. Followed by a clear line: "Reply YES to approve and I will crack on" or "Let me know either way".
- Send it via your messaging tool rather than personal WhatsApp where possible, so the approval lives against the job record rather than in a thread you have to scroll back through six weeks later. CMA logs every variation message against the client and quote in one place; if you are doing this from your phone, at minimum save a screenshot of the approval against the job.
- Update the quote itself with a new line, not just the message. The customer sees the same line on the message, on the updated quote, and on the eventual invoice. By the time the final invoice arrives the variation has been visible three times and there is nothing to argue about.
When to absorb the cost yourself - and how to flag it without losing face
Sometimes the right call is to swallow the extra. The job is small, the relationship matters more than the £140, the customer has been good throughout, or the miscalculation was on something the customer could not reasonably have known about. In those cases, the worst thing you can do is absorb the cost silently and then resent it. Tell the customer you are taking the hit - they will remember it next time they need a tradesperson, and the referrals from "he flagged a problem and did not charge me extra for it" travel further than the £140 ever would have.
- Wording: "I have spent an extra few hours on the plastering side - I am not going to charge you for it because I priced it tight and that is on me, but wanted to flag it so the next quote I do for you reflects the real time."
- Use this version sparingly. Doing it on every job trains customers to expect it; doing it once on a small overrun in a long relationship buys you genuine loyalty.
Un flux de travail simple pour de meilleurs devis
The moment you discover something - stop, take a photo, work out which of the three causes you are in.
Make the call the same day. A "quick heads-up" text in the moment beats a polished email tomorrow.
State the news, show the evidence, give the new number, ask for a clear yes or no.
Send the written version within the hour. One short paragraph, a line item, a yes-or-no ask, logged against the job in your messaging tool.
Update the quote with the new line so the variation is visible on the quote, the message, and the eventual invoice.
Most mid-job price conversations go wrong for the same three reasons every time: the tradesperson treats discovery, extras, and their own miscalculation as the same conversation; they leave the call too long; or they get a verbal yes and never put it in writing. Fix those three and the conversation goes from the worst part of the job to a five-minute task you do the same day as the discovery.
Pick the version of the script above that matches the next variation you have to raise, send it within an hour of the discovery, and watch the conversation that used to drag on for a week land in a single exchange.
Questions fréquentes
How do I tell a customer the job will cost more without losing them?
Work out which of the three causes you are in first - genuine discovery, customer-requested extras, or your own miscalculation - because each needs a different tone. Make the call the same day you know, state the news factually with the new total in the second sentence, and follow up in writing within the hour with a line item and a clear yes-or-no ask. Customers almost never object to the cost; they object to feeling ambushed.
When should I tell the customer about extra costs?
The same day you discover them. For discovery (rot, asbestos, hidden services) call as soon as you can take a photo. For customer-requested extras, agree the cost before you start the extra work, not after. For your own miscalculation, raise it as soon as you realise - usually by the end of the first day. The cost of the conversation doubles every day you wait.
What should I do if I underpriced the job?
Tell the customer, in plain wording, before the end of the job rather than at the final invoice. "I priced this at half a day and it is going to be a full day - wanted to flag it now rather than at the end" gets you respect from most customers and an honest conversation about whether you split the difference, absorb it, or charge the lot. Hiding it and slipping it onto the final invoice is how you lose the customer and the referral.
How do I get a customer to approve a variation in writing?
Send a single message the same day stating what changed, why it changed, what it costs, and the new total, ending with a clear "Reply YES to approve and I will crack on". Update the quote itself with the new line so the variation appears on the message, the quote, and the eventual invoice. By the time the final invoice arrives the variation has been visible three times and there is nothing left to argue about.
Should I ever absorb the extra cost myself?
Sometimes - when the job is small, the relationship matters more than the money, and the overrun was on something you priced tight. The trick is to tell the customer you are absorbing it rather than swallowing it silently. "I priced it tight and that is on me, but wanted to flag it so the next quote reflects the real time" earns you referrals; absorbing it silently breeds resentment that comes out on the next job.
Ressources associées
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Fonctionnalités CMA associées
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