Cost control · August 2026 · 8 min read
A practical guide to a bill of quantities people will use
A BOQ fails when it is too vague to price or too detailed to maintain. Here is a line structure that survives a live project.
A bill of quantities is useful when someone other than its author can find a line and trust the amount. That means a code, a short description, a unit, a quantity, and a rate. The amount should be the product of the quantity and the rate, not a number typed beside them.
Codes matter more than prose. “Brickwork, external, ground floor” is hard to scan in a list of two hundred lines. A code plus a category lets the commercial team filter to one trade. Keep the description specific enough to know what was priced, and short enough that a site engineer recognises it.
Units have to match how the work is bought. Square metres, cubic metres, numbers, and running metres should not be mixed on one line. If the unit is wrong, every later quantity update multiplies the error.
Do not hide contingency inside a rate you cannot explain. A separate line, with its own quantity and rate, is easier to reduce when the risk does not happen. The same applies to provisional sums: they are lines, not notes under the total.
In Best CPMS each of those lines belongs to one project. The server stores the amount as quantity times rate. Expenses and payments on that project are the spend and the cash beside the bill, which is what the cost report exports.