Free model railroad DCC bus wire gauge and feeder spacing calculator. Estimate voltage drop, get wiring fixes, and plan N, HO, O, or G scale layouts before you solder track.
A fast, single-page web tool for model railroaders planning DCC wiring. Type your scale, bus length, gauge, and feeders — get an instant voltage-drop estimate, a risk verdict (Safe / Acceptable / Borderline / Risky), and a punch list of fixes.
Live: https://dcc-bus-feeder-calculator.vercel.app/
- Voltage drop estimator using standard copper AWG resistance tables and the full out-and-back electrical path.
- Scale-aware defaults for N, HO, O, G, and Custom — voltage, target drop %, and feeder spacing.
- Risk classification — Safe, Acceptable, Borderline, Risky — based on percent drop.
- End-fed vs. center-fed bus modeling so you can see what halving the run actually buys you.
- Bus type penalty for tinned copper (small but real practical difference).
- Plain-English fixes — heavier gauge, more feeders, center-feed, split into districts, add a booster.
- Shopping checklist of materials that match the wiring plan.
- No backend, no accounts, no tracking. Runs entirely in the browser.
- Model railroaders sizing bus wire before a wire order.
- Builders troubleshooting stalls, decoder glitches, or dim headlights on long runs.
- Anyone deciding between 14 AWG and 12 AWG bus, or 18 AWG and 22 AWG feeders.
npm install
npm run devnpm run build
npm run previewVoltage drop = Current × Resistance
Resistance = (effective bus length × 2) × AWG resistance/ft × bus-type factor
+ (feeder length × 2) × AWG resistance/ft
Drop % = (Voltage drop / DCC voltage) × 100
- Effective bus length is halved when center-fed (the farthest run is half the total).
- Out-and-back doubles the conductor length, because current goes through two wires.
- AWG resistance uses standard reference values at ~20°C, ohms per 1000 ft, for 10–22 AWG copper.
- Assumed load is capped per scale so tiny beginner layouts don't get scared off by a 5 A booster.
Dirty rail, weak solder joints, oxidized rail joiners, contact resistance, decoder sensitivity, poor wheel pickup, or feeder parallel behavior. Treat the result as a wiring-plan check, not a guarantee.
Based on standard copper resistance, this configuration meets common DCC power stability guidelines. Does not account for connection quality or dirty track.
- Vite + React + TypeScript
- lucide-react icons
- No backend, no API keys, no analytics
When publishing on GitHub, add these topics to the repo for discovery:
dcc, model-railroad, model-trains, model-railway, wiring-calculator,
voltage-drop, awg, bus-wire, feeder-spacing, ho-scale, n-scale, o-scale,
g-scale, calculator, react, vite, typescript, electronics, hobby
Built by Jacob Britten.