As a rebar estimator, your duties are primarily to estimate the number of reinforced steel bars (rebar) and other related construction or manufacturing materials needed for a specific project. Contractors often use rebar to enhance concrete or stone structures, and so as an estimator, you determine the amount of rebar required based on blueprints, plans, drawings, and measurements. You collect relevant data and use computer-aided design or building information modeling software to arrive at accurate estimates. Some estimators use specialized applications, such as aSa Rebar Estimating Software.