Free engineering calculators built by a licensed PE
Open-channel hydraulics, pipe flow, weir & orifice equations, and stormwater calculators — each one with the formula spelled out so you can verify the math. No login, no paywall, no tracking beyond what AdSense requires. Built for working engineers, not students cramming for the FE.
Free reference cards
Single-page printable cheat sheets for the values engineers look up over and over. Save the PDF, pin it above your desk.
What's coming next
More tools are added weekly. Planned next: culvert hydraulics (inlet/outlet control), stormwater pond routing, NRCS curve number runoff, and structural beam deflection. If there's a calculator you'd like that isn't here, the repo's issues page is the place to ask.
Why another engineering calculator site?
Most of the existing options either bury the math behind ads, leave you guessing what coefficients they're using, or were built for a freshman thermodynamics class twenty years ago and never updated. Every PE-Calc tool shows the formula being applied, names every variable, cites a reference, and lets you hand-check the result. The calculators run entirely in your browser — nothing leaves your machine.