Most cost lists for sellers are alphabetical, which is no help at all, because the question people actually have is when they need the money. A sale spends a small amount up front, almost nothing in the middle, and a large amount on the day it completes, out of funds that only exist on that day. This page puts the same costs in the order they fall due.
Before the board goes up
The only unavoidable pre-marketing cost is the EPC, because you must order one for potential buyers before you market the property to sell, and it is valid for ten years so an existing one may still be good. Beyond that, anything you spend preparing the house is discretionary. It is worth being deliberate here, because this is the money you lose if the sale never happens, and it is the only part of the sheet you can be sure of spending.
While the sale is progressing
Between acceptance and exchange, the seller's outgoings are usually small. The conveyancer may ask for money on account to cover disbursements, and there may be documents to obtain for a leasehold property, which can take time as well as money. The important thing in this stretch is not the size of the payments but the fact that they continue whether or not the transaction completes, so a sale that collapses late costs more than one that collapses early.
On completion day
This is where the two large lines land, and they land out of the sale proceeds rather than out of your bank account. The conveyancer receives the money, redeems the mortgage, settles their own bill and the agent's fee, and sends you the balance. That balance is the number the whole exercise has been about. If you are buying on the same day, it is also the number your onward purchase depends on, which is the reason to have worked it out at the start rather than to discover it in a completion statement.
Questions people ask about costs involved in selling a house
Do I need cash available to sell?
A small amount, mostly the EPC and any money on account your conveyancer asks for. The large fees come out of the completion funds.
What happens to the money on the day?
The conveyancer receives the sale funds, redeems any mortgage, pays their own bill and the agent, and sends you what is left.
When is the agent actually paid?
Normally on completion out of the proceeds, but the trigger for liability is set by your contract, which the agent had to explain before you signed it.