Every equation used by ConstrCalc® — in plain view. Zero hidden multipliers, zero AI predictions. Educational reference only.
Subtotal = Materials + Labor + Equipment + Legal
Direct cost total before overhead, profit, and taxes. Every input is user-entered — ConstrCalc® never inserts a hidden line item.
Overhead = Subtotal × (Overhead% ÷ 100)
The share of business operating cost (office rent, admin, insurance, marketing) allocated to this project. You choose the percentage; ConstrCalc® never assumes one.
Profit = (Subtotal + Overhead) × (Profit% ÷ 100)
Contractor margin computed on top of Subtotal + Overhead, matching most professional bidding conventions.
Grand Total = Subtotal + Overhead + Profit + Taxes
The final project figure produced by ConstrCalc®. Every term is either a user input or a deterministic derivation of user inputs.
Cost per ft² = Grand Total ÷ Area (in ft²)
Per-unit metric for comparing projects. Deterministic — never an average, never a prediction.
Cost per m² = Grand Total ÷ Area (in m²)
Per-unit metric in metric units. Uses the deterministic ft² ↔ m² constant (× 0.092903).
Cost per Floor = Grand Total ÷ Number of Floors
Straight-line distribution across floors. Assumes equal floor cost — no weighting.
Cost per Month = Grand Total ÷ Project Duration (months)
Straight-line monthly distribution over the project timeline. Useful for cash-flow planning.
m² = ft² × 0.092903 ft² = m² × 10.7639
Deterministic imperial ↔ metric area conversion using the internationally accepted constant.
hectare = acre × 0.404686 acre = hectare × 2.47105
Land-scale area conversion between US/UK and metric units.
1 tsubo = 3.30579 m² 1 ping = 3.30579 m² 1 pyeong = 3.30579 m²
East-Asian traditional area units (Japan, Taiwan, Korea) — all defined as 6 × 6 shaku (Japanese foot). Same size, three names.
Contingency = user-entered line item (typically 5–10% of project scope)
ConstrCalc® does NOT auto-add contingency. If you want a reserve, enter it as a Legal / Additional line item or increase your Overhead percentage.
Every formula listed here is used by ConstrCalc® — nothing else. All inputs come from you.