Estimates, not guarantees
Material, cost, geometry and quantity calculators produce estimates from the inputs and assumptions shown on each page. Actual requirements can differ because of detailing, waste, cuts, tolerances, workmanship, site conditions, supplier packaging and product specifications.
Structural calculators
Beam, bending, span, rebar and related structural tools are intended for preliminary educational or checking purposes. They do not perform a complete structural design and may omit stability, connections, load combinations, serviceability criteria, fire requirements, seismic effects and other code checks.
HVAC and building-physics calculators
Cooling, ventilation and heat-loss tools provide simplified estimates. Final equipment sizing and building-performance decisions should use project-specific climate data, envelope properties, ventilation requirements, occupancy, internal loads and manufacturer information.
Codes and local requirements
Building codes, standards and accepted practices vary by location and project type. The user is responsible for identifying and complying with the requirements that apply to the project.
Before construction: Have critical calculations and design decisions reviewed by an appropriately qualified professional where required.