Tools for the calculations before the drawing

Yes, 100% free with no paywall, no credit card, and no mandatory login. You can run unlimited calculations, perform direct inline editing, export structured CSVs, and print clean engineering sheets ready for plan review submittals.

The Electrical Panel Schedule implements NEC Article 220 demand factors (lighting, small appliance, fixed appliances, cooking, dryers, and HVAC). The Available Fault Current calculator runs the standard IEEE 141/242 and Bussmann Point-to-Point method with exact C-constants for copper/aluminum conductors in PVC or metallic raceways. The Plumbing Fixture Unit calculator implements 2021 International Plumbing Code (IPC) and Uniform Plumbing Code (UPC) tables.

Yes. Every calculator includes dedicated print styles tailored for CAD engineering drawing sheets. Clicking "Print Sheet" or pressing Ctrl+P formats the sheet directly for landscape or portrait permit submittals with clean black borders and zero blank pages.

The schedule alternates circuit slots across Phase A and Phase B (slots 1 & 2 on Phase A, 3 & 4 on Phase B, etc.). Selecting a 2-pole breaker on any odd or even slot automatically links the slot two spaces below it as a linked circuit, splits the load evenly across both phases (50% to Phase A, 50% to Phase B), and calculates real-time phase balance percentage.

It determines available short-circuit amperes starting from the utility transformer (or given utility fault current) through service entrance feeders and subpanel feeder runs using the standard point-to-point formula: f = (2 * L * I) / (N * C * E) and M = 1 / (1 + f). It directly calculates available fault current at main disconnect and subpanel terminals to verify equipment AIC ratings satisfy NEC 110.9.

Fixture quantities are multiplied by code-mandated water supply fixture units (WSFU) and drainage fixture units (DFU). Total WSFU is converted into probable simultaneous peak flow (GPM) via Hunter’s Curve for flush tank or flushometer systems. The tool adds continuous irrigation flow and calculates minimum water service pipe diameter, water meter size, and gravity building sewer diameter.

Yes. Each tool downloads a PDF laid out as a schedule sheet, ready to drop into a permit set, and "Send to my email" emails it to you: type your address and it arrives in a minute, with no account. HearthPlans also drafts the full architectural and MEP set when you need the drawings themselves.