BendMarks: Conduit Bending

The conduit and code calculator that shows its work.

Most calculators hand you a number and expect you to trust it. BendMarks gives you the number, the formula behind it, your own values substituted into that formula, and a labeled diagram of the bend. Check the math on the tailgate. Hand the phone to an apprentice and walk them through it. Catch the mistake before you cut.

For the electrician who wants to know why the math works, and the apprentice still learning it.

WHAT IT DOES

Conduit bending: offset, rolling offset, 3-point saddle, 4-point saddle, 90 degree stub-up and kick bends, each with a labeled diagram and exact mark distances.

Voltage drop: single-phase and three-phase, copper or aluminum, with a clear pass or fail against the NEC 3% and 5% targets.

Conduit fill: NEC Chapter 9 percentages, drawn as a cross section for any mix of wire.

Box fill: NEC 314.16(B) for conductors, devices, grounds and clamps.

Obstruction planner: give it the real pipe or wide obstruction in front of you and it returns the bend marks.

Apprentice drill mode: random bend problems that make you commit to an answer before they reveal the math.

Show your work: every result opens into the formula with your numbers in it, explained in plain language, so you learn the math while you use it.

Built for the field: oversized tap targets for gloved hands, a fraction-native keypad, and a sunlight mode that thickens every line so the diagrams hold up in direct sun.

Recents: your last 20 calculations, one tap away.

WHAT IT DOES NOT DO

No ads. No subscription. No account to create. No tracking, and no advertising identifier. One payment, and the whole app is yours.

Every calculator runs offline, so a dead zone in a basement or a mechanical room changes nothing. Your measurements and results stay on the phone. The app reports crashes and performance problems so the next version breaks less, and that is the only thing it ever sends.

Sources: Benfield's Conduit Bending and Fabrication, Ugly's Electrical References, NEC 2023 Chapter 9. Every NEC value is cited to its section. This is a learning and field reference tool, not a substitute for code review or professional judgment. Always verify against your local code and a licensed electrician.