---
title: "Determines the minimum AWG (American Wire Gauge) conductor size for a given current, voltage, one-way cable distance, and maximum allowable voltage drop percentage. Supports copper and aluminum conductors. Computes round-trip resistance, actual voltage drop in volts and percent, and wire cross-sectional area. Essential for DC solar runs, battery bank wiring, EV charging circuits, and low-voltage landscape lighting. NEC recommends 3% max drop for branch circuits and 5% total including feeder. Outputs the smallest AWG that satisfies the drop constraint."
method: POST
path: "/api/wire_gauge"
tags: ["power"]
---

# Determines the minimum AWG (American Wire Gauge) conductor size for a given current, voltage, one-way cable distance, and maximum allowable voltage drop percentage. Supports copper and aluminum conductors. Computes round-trip resistance, actual voltage drop in volts and percent, and wire cross-sectional area. Essential for DC solar runs, battery bank wiring, EV charging circuits, and low-voltage landscape lighting. NEC recommends 3% max drop for branch circuits and 5% total including feeder. Outputs the smallest AWG that satisfies the drop constraint.

`POST /api/wire_gauge`

## Request

- Base URL: `https://calc.engineer`
- URL: `https://calc.engineer/api/wire_gauge`
- Auth: none declared

## Request body

- object
  - `current_amps` number, required: Load current in amperes (A)
  - `voltage` number, required: System voltage (V)
  - `distance_m` number, required: One-way conductor distance in meters
  - `max_drop_pct` number: Maximum allowable voltage drop as percentage (default 3%)
  - `conductor` 'copper' | 'aluminum': Conductor material: copper or aluminum

## Response `200`

Computed result for wire_gauge

- object
  - `result` object, required
    - `recommended_awg` number, required: Recommended AWG gauge number (smaller number = thicker wire)
    - `recommended_awg_label` string, required: Human-readable AWG label (e.g. '10' or '0000 (4/0)')
    - `actual_drop_pct` number, required: Actual voltage drop percentage with recommended gauge
    - `actual_drop_v` number, required: Actual voltage drop in volts
    - `resistance_per_m` number, required: Resistance per meter of the recommended gauge (ohm/m)
    - `wire_area_mm2` number, required: Cross-sectional area of recommended gauge in mm^2
    - `insufficient` boolean, required: True if even the largest AWG (4/0) cannot meet the voltage drop target
  - `tool` string, required
  - `version` string, required
  - `computed_at` string, date-time, required
  - `chain` object, required
    - `feeds` unknown[]
      - unknown
    - `accepts_from` unknown[]
      - unknown

## Other responses

- `400`: Validation error or invalid JSON
- `404`: Tool not found

---

[API](https://skmtc.dev/calc/apis/calc-engineer-api.md) · [All operations](https://skmtc.dev/calc/apis/calc-engineer-api/llms.txt) · [OpenAPI document](https://skmtc.dev/calc/apis/calc-engineer-api/revisions/8830480ec488?raw)