Labor burden is the additional employer cost on top of an employee's base wage. Components include: federal and state payroll taxes (FICA, FUTA, SUTA), workers' compensation insurance, general liability allocation, health insurance, retirement contributions, paid time off, training, vehicle allowance, and tool allowance. Adding burden to the base wage produces the fully burdened labor rate, which is what estimators use to price labor.
Typical burden runs 25 to 45% of base wage in commercial construction. Trades with high workers' comp rates (roofing, steel) run higher. Office staff classifications run lower. Estimators who price using only base wage systematically underbid by 25 to 45% on labor, which on a labor-heavy project can wipe out profit. Calculate your shop's actual burden rate annually from payroll and accounting data, then update estimating templates to use the current burdened rate.