Gross Profit, GP, is equal to the Gross Income minus the COGS. We can consider Gross Income and the Gross Sales price the same in this example.
COGS, Cost of Goods Sold, in construction is the direct costs of delivering a job or the labor costs plus the materials cost plus the commission cost.
A Man Day, MD, is 8 hours.
Gross Profit per Man Day, GPMD is the amount of GP on man brings back to the company in one man day after his labor and any materials cost have been deducted from the GI or the Sales price of the job.