FREE
CALCULATORS
MEP sizing that shows its work. Pick the code book and edition your jurisdiction enforces; get the size, the math, and the citation — in your browser, free, no sign-in. Wrong number? Tell us with one click and we fix it.
DUCT SIZING
Equal friction and constant velocity for round, rectangular, and flat-oval duct — Darcy-Weisbach + Colebrook, with altitude and temperature correction.
Size duct → WATER · DWV · GAS · STORM — IPC / UPCPIPE SIZING
Domestic water by WSFU and Hunter's curve, hydronic by friction rate, DWV by DFU, fuel gas by longest length, storm by rainfall — on the code edition you pick.
Size pipe → ELECTRICAL · NEC 2017 / 2020 / 2023CONDUIT FILL
Fill per Chapter 9 Tables 1, 4, 5 and 8, voltage drop per Table 9, ampacity per 310.16 with correction and adjustment factors — cited per edition.
Size conduit →Because you'll remember who handed you the wrench
These calculators are free forever — like our Revit Bulk Export. No trial clock, no email wall — your inputs never leave your browser. We count only anonymous, cookieless usage (which calculator, which code edition) so we know what to improve. Every result carries its citation so you can defend it in a coordination meeting, and every page has a FEEDBACK button that lands directly with the team that builds our paid Revit, Navisworks, and Fusion tools. That's the trade: we give you the math, you tell us what to build next.