Find the Right Wire Size for Any Project
A free browser-based wire gauge calculator that recommends the correct AWG wire size based on current, distance, and maximum allowable voltage drop. Supports copper and aluminum wires, includes AWG-to-mm² conversion, ampacity reference table, and practical presets for LED strips, outlets, EV chargers, and solar panels.
How to Calculate Wire Gauge
Set the load current in amps, one-way wire distance in meters or feet, and system voltage.
Choose the maximum acceptable voltage drop (typically 3% for branch circuits, 5% for feeders).
See the recommended AWG gauge, cross-section in mm², actual voltage drop, and power loss in the wire.
Select the optimal wire size based on current, distance, and voltage drop
Features
FAQ
What is AWG?
American Wire Gauge — a standardized system for wire diameters. Lower AWG = thicker wire. AWG 10 ≈ 5.26 mm², AWG 14 ≈ 2.08 mm². Used primarily in North America.
How is voltage drop calculated?
Vdrop = 2 × I × R × L, where I is current, R is resistance per meter, L is one-way distance. Factor of 2 accounts for the round trip (supply + return wire).
What voltage drop is acceptable?
NEC recommends max 3% for branch circuits and 5% total (feeder + branch). For 12V DC systems, even 3% (0.36V) can affect LED brightness, so use thicker wire.
Copper vs aluminum — which to use?
Copper has 61% lower resistance and is standard for most wiring. Aluminum is cheaper and lighter but requires larger gauges and special connectors to prevent corrosion.
What is ampacity?
The maximum current a wire can carry continuously without exceeding its temperature rating. Depends on wire gauge, insulation type, ambient temperature, and installation method.
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