Here is a number that stops most owners in their tracks.
If your gross margin is 40% and you put your prices up by 10%, you could lose one in five of your customers and still make exactly the same gross profit.
Not similar. The same.
The formula is simple enough to do on the back of an envelope. The percentage of customers you can afford to lose is the rise divided by (your margin plus the rise). Ten divided by fifty is twenty percent. There is a calculator here if you want to put your own numbers in.
Why the number is always higher than people expect
Because a price rise costs you nothing to deliver. No extra materials, no extra hours, no extra diesel. Every penny lands straight on your gross profit. That is why it is the single most powerful lever in a small business, and the one that gets left alone the longest.
Meanwhile your rent went up. Your insurance went up. Your materials certainly went up. And your price list is the same one you wrote in 2023, because changing it felt like a conversation you did not want to have.
How to actually do it
Not by email, and not to everyone at once
Start with new enquiries only. Today. Nobody has to be told anything — the new price is simply the price. You will find out within a fortnight whether it makes any difference at all, and in most trades it does not.
Existing customers get notice and a reason
Thirty days, in writing, with one honest sentence about why. Not an apology and not a paragraph of justification, because both invite negotiation. Something like: “From 1 October my hourly rate goes to £X. Costs have risen and I have held my prices since 2023.” That is the whole message.
Have an answer ready for the two who push back
Because two will, and if you have not thought about it you will fold. The answer is not a discount. It is usually a smaller scope at the old price, which lets them keep their budget and lets you keep your rate.
What actually happens
Almost always less than you fear. A handful of grumbles, one or two people who drift, and a business that is measurably better off for the same work. The customers who leave over ten percent were rarely the ones you wanted.
The hard part was never the arithmetic. It was being the person who sends the email — which is exactly the kind of thing that does not happen unless somebody is expecting you to do it.