Solar Wire Size Calculator - Electronicsinfos

When most people start working on a solar setup, they generally focus on the panels, batteries, and possibly the inverter. However, very few people consider the size of the wires. And to be honest, that minor detail can lead to major headaches.

You run the risk of losing valuable power or even having dangerously hot conditions if your wires are too thin. If you go too deep, you will only be wasting your money. A wire size calculator is useful because it's a way to balance your solar system.

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What’s a Solar Wire Size Calculator?

A solar wire size calculator just helps you figure out what thickness of wire you need so your system runs properly. You don’t want wires that are too thin — they can overheat or waste electricity. But you also don’t want to go too thick and waste money on expensive cable you don’t need.

The calculator just asks you for a few details, like how far the wire is going, what voltage your system is using (12V, 24V, etc.), how much current your system pulls, and how much voltage drop is acceptable (usually no more than 3%).

Solar Wire Size Calculator

Estimate cable cross-section (mm²) and recommended common cable sizes based on voltage drop.

System Type DC (Solar PV) — recommended Single-phase AC Three-phase AC (use result as guidance)

System Voltage (V)

Power (W) — OR leave blank and enter Current (A)

Current (A) — OR leave blank and enter Power (W)

One-way cable length (meters) This is the distance from panel to inverter/charge controller (one-way). Round-trip length is used for voltage drop.

Acceptable Voltage Drop (%)

Choose Conductor Material Copper Aluminum

Temperature derating? (optional) No derating (1.00) 10% derate (0.90) 20% derate (0.80) This scales ampacity check. Use appropriate derating for high ambient temps or bundling.

Note: This calculator uses copper resistivity = 1.724×10⁻⁸ Ω·m and aluminium = 2.82×10⁻⁸ Ω·m. It computes conductor area (mm²) from the chosen voltage drop and suggests the nearest common cable sizes. It does not replace site-specific design or local electrical codes.

Run the calculation to see results.

Suggested common cable sizes

Ampacity reference (typical)

Cable (mm²)	Typical Max Continuous Current (A)
1.5	15
2.5	20–25
4	25–32
6	32–40
10	40–55
16	63–80
25	85–110
35	125–150
50	170–200

These are guideline figures — actual permitted currents depend on insulation, installation method and local codes.