How it works
The contingency is held back from the total: a $46,000 budget with 10% leaves $41,400 for the planned work and $4,600 in reserve. Each job counts at the best number you have: the final cost if you know it, otherwise the quote you accepted, otherwise the first estimate. When the expected total passes the work budget, the difference comes out of the contingency. The versus-estimates line shows how far the quotes and final costs have moved from your first estimates, which is usually the earliest warning. The worked example is in how much contingency a renovation needs.