Construction Glossary
Prime Cost Sum
Also known as PC Sum
Definition
A prime cost sum, or PC sum, is an allowance in a price for materials or goods that the client will choose later, such as kitchen units, tiles or sanitaryware. The figure covers the supply only, and labour, fixing and profit are priced separately. When the client picks the actual product, the PC sum is adjusted to the real cost. It lets pricing proceed before final selections are made.
Prime cost sums are common where the client wants to choose finishes themselves. The estimate carries a sensible supply allowance, for example a figure per square metre for floor tiles, while the labour to fit them is measured and priced as normal.
Once the client confirms their choice, the supply allowance is swapped for the genuine cost and the contract sum is adjusted up or down accordingly.
Why it matters
PC sums let you price and start a job before the client has chosen every fitting, without absorbing the risk of their taste. Set the allowance too low and you face an awkward adjustment later, so a realistic PC sum keeps the relationship and the budget on track.
We set realistic prime cost sums in your estimate for client-selected items so the supply cost is allowed for and easy to adjust later.
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