There are six lines that come off a UK house sale, and only two of them are negotiable once the sale is agreed. Most guides list them and stop, which leaves you no better off, because the total depends entirely on which numbers go in. This page names each line, says who sets it and when it is fixed, and hands the arithmetic to a sheet you can put your own figures into.
The agent's fee, and the only moment you can change it
The agent's fee is the biggest line and the only one that is genuinely negotiable, and the moment to negotiate it is before you sign, not after an offer comes in. The Estate Agents Act 1979 makes the agent give you, before you enter the contract, the circumstances in which you become liable to pay and the amount of their remuneration. So the number exists in writing before you commit. Read it against the fee models rather than against another agent's headline percentage: a commission is a share of whatever the house sells for, a fixed fee is the same whatever it sells for, and the two cross over at a sale price you can work out in about a minute.
VAT, which is not a separate line so much as a fifth of the first one
Agency fees carry VAT at the standard rate of 20 percent, and this is where quoted figures diverge most. An agent quoting a rate plus VAT and an agent quoting a rate a fifth higher with VAT already in it are charging the same thing, and an agent who quotes a percentage without saying which is leaving you to guess at a fifth of the largest line on the sheet. When you compare two quotes, put both on the same footing first. The sheet does that for you: it takes the fee and the VAT position separately, so two quotes stated differently can be read side by side.
Conveyancing, the EPC and the things that are fixed before you market
The conveyancer's fee is quoted up front and is largely fixed by the property rather than by you: leasehold costs more than freehold, a mortgage to redeem adds work, and the disbursements the firm pays on your behalf are what they are. The EPC is a legal requirement rather than a choice, because you must order one for potential buyers before you market the property to sell, and it is valid for ten years, so if the last one is recent you already have it. Removals and any pre-sale work sit outside the transaction entirely and are the lines most people underestimate.
What the sheet is actually for
The reason to put these into a worksheet rather than a list is that the answer you want is not the total cost, it is what is left. Sale price, minus the agent's fee and its VAT, minus conveyancing and the smaller fixed lines, minus whatever mortgage is outstanding, is the figure that decides what you can afford next. That is the figure an agent hands a seller at valuation, and it is the one this site's free sheet produces from your own numbers rather than from a national average that is not about your house.
Questions people ask about cost of selling a house
Which of these costs can I actually negotiate?
In practice the agent's fee, and the conveyancing quote if you shop it before you instruct. The EPC is a legal requirement, and removals are priced by the job.
Do I pay the agent if the sale falls through?
It depends on the contract, which is why the Act makes the agent set out in advance the circumstances in which you become liable to pay. Read that clause before you sign, not after an offer is accepted.
Is there a single average cost of selling a house?
No, and a number presented as one is doing you a disservice. The largest line is a percentage of your sale price under a contract you have not signed yet, so the total is your arithmetic rather than the country's.