Labor rate is the hourly cost of a specific worker classification used to build labor estimates. There are three standard versions: base wage (what the worker takes home), burdened rate (base wage plus all employer costs from payroll taxes through benefits), and billing rate (burdened rate plus markup, used when billing time-and-materials work). Estimators use burdened rate for internal bidding and billing rate for T&M work.
Labor rates vary by trade classification (apprentice / journeyman / foreman / superintendent), by union or non-union status, by geographic market, and by Davis-Bacon prevailing wage on federal projects. The estimator should maintain a labor rate table for the shop's actual classifications, updated whenever wages or burden change. Using stale rates is one of the most common reasons bids drift away from actual cost over time.