For Electricians
The calculator that shows its work.
Four NEC-based electrical calculators in one offline app. Every answer expands into the formula, the substituted numbers, and a labeled diagram.
Four NEC-based electrical calculators in one offline app. Every answer expands into the formula, the substituted numbers, and a labeled diagram.
What's Inside
Pick a calculator. Enter your numbers. Learn the math. Every result expands to show the formula with substituted values, step-by-step derivation, and a labeled diagram.
Offsets, rolling offsets, 3-point and 4-point saddles, 90° stub-ups, and kick bends. Every bend type an electrician needs.
Know if your run is too long before you pull wire. Pass / warn / fail in one tap, single- or three-phase, copper or aluminum.
Know if your wires fit before you pull them. Pick a conduit, drop in your conductors, see the fill at a glance — code-compliant under NEC Ch.9 Table 1.
Stop overstuffing boxes. Add your conductors, devices, and grounds — instant pass/fail before the inspector sees it.
Yesterday's bend, last week's voltage drop — your last 20 calculations stay one tap away so re-running a job takes no math.
90°, offset, three-point saddle, four-point saddle, rolling offset, kick — every bend you make in the field, calculated to the deduct.
Export any result as a clean image card — text the foreman, attach to the inspection, drop into the daily report.
Switch between NEC code cycles in one tap so you stay compliant whether your jurisdiction adopted 2017, 2020, or 2023.
See It In Action
High-contrast dark UI. Glove-friendly tap targets. Results you can actually read on a job site.
How It Works
BendMarks doesn't just give you an answer. It teaches you how to get there.
Choose from bending, voltage drop, conduit fill, or box fill. Each covers every variation you'll hit in the field.
Glove-friendly controls. Segmented pickers and numeric inputs sized for real hands in real conditions.
Every result expands to show the formula, substituted values, step-by-step derivation, and a labeled diagram.
Why BendMarks
Built by an electrician, for electricians. Every design decision puts the trade first.
Works everywhere. Basement, attic, middle of nowhere. No signal required.
No accounts. No analytics. No data collection. Your calculations stay on your device.
Pay once, own it forever. No recurring charges, no feature gates, no upsells.
Calculations based on Benfield's, Ugly's Electrical References, and NEC code tables.
Download BendMarks and start learning the math behind every calculation.