Prime cost sum
A prime cost sum, usually shortened to PC sum, is an allowance in a quote for supplying a specific item the customer has not chosen yet. It covers the supply cost of the item only, with labour, fixing and the contractor's margin priced separately.
In practice for trades
A PC sum solves a common problem: the customer wants a price today but has not picked the taps, the tiles, the boiler or the kitchen. Rather than guess and get it wrong in either direction, you set a stated allowance for the item and adjust when they choose.
The key is that a PC sum is a supply figure. If the customer picks a suite that costs £350 more, the price goes up by £350, and extra fitting time is a separate adjustment. Trades who fold labour into the PC sum end up absorbing fitting time they never priced.
Keep it specific. "PC sum: £600 for bathroom suite (supply only)" is a figure you can defend. "PC sum: £600 for bathroom" invites an argument about whether it included the screen, the taps and the waste.
Where a PC sum sits alongside a provisional sum on the same quote, the pairing is easy to remember: a PC sum is an allowance for goods, a provisional sum is an allowance for work.
Worked example
A bathroom quote carries a £600 PC sum for the suite, supply only. The customer chooses a suite at £950. The account is adjusted by £350, and the different waste arrangement the new basin needs is agreed separately at £120 before the work is done.
Related terms
- Provisional sum: the equivalent allowance for work that cannot be priced yet
- Quote vs estimate: whether the surrounding price is fixed or indicative
Price it in FieldHive
Carry supply allowances and labour separately, instead of padding one figure, with the Trade Job Pricing Calculator.
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