Net profit margin, on the other hand, tells the full story. It represents the percentage of revenue left over after all overhead, interest, depreciation and taxes are subtracted. The benchmark range here is 5–8% for well managed companies. (Public builders or large private firms could see slightly higher margins due to volume and operational efficiencies.) While these percentages may seem modest, it’s the margin that ultimately funds growth, cushions downturns and satisfies stakeholders.

https://www.jmco.com/articles/construction/performance-benchmarks-construction-companies/