Estimating Subcontractor Bids

You can enter unit costs into the BidMagic estimating software, using bids from your construction subcontractors.

Figuring Costs from Subcontractor Firm Bids

In the case of 'firm bid' subcontractors, you'll only need to use the unit prices in BidMagic to calculate a ballpark price, since you'll be able to replace the calculated costs with the subcontractor's firm bid to you before turning in the bid yourself (see pages 255-256).

Start by breaking the subcontractor's bid down into a few reasonable components. For example, an electrician's bid might be broken down into rough-in wiring, plugs/outlets, and fixtures. Allocate the bid price among them as best you can, using information from the subcontractor, estimating books, or your own experience.

You can then take each 'chunk' of work and set it up as a unit price. Try to use quantities that are easy to measure off blueprints--for example, plug/switch counts, fixture counts, and number of rooms.

Use the 'rule of thumb' method to put together a unit price for each component of the firm bid. To double-check your unit prices, type in the actual unit quantities on a project, and make sure that the calculated price is close to the subcontractor's firm bid.

When you first start a project estimate, very quickly enter unit price information for the trade--it will give you a quick 'planning' price right off. Later on, when you receive a firm bid from the subcontractor, you can replace the calculated price with the actual bid by switching to a flat price for the category handled by the subcontractor (see pages 255-256).