WireSizer Pro

WireSizer Pro is the go-to cable sizing tool for solar installers, marine electricians, and inverter engineers. Stop guessing — get the right cable cross-section and fuse rating in seconds.

⚡ WHAT IT DOES
Enter your system voltage, load current, run distance, and maximum voltage drop — WireSizer Pro instantly calculates the minimum cable size and correct fuse or breaker rating for your DC installation.

🔧 KEY FEATURES
• Cable sizing in mm² (IEC) and AWG (NEC/ABYC)
• Fuse and circuit breaker sizing with 125% NEC safety margin
• Supports copper and aluminium conductors
• Temperature correction (IEC 60228 resistivity values)
• Installation derating — open air, conduit, bundled, submerged
• Works for 12V, 24V, 48V and any custom DC voltage
• Save and name calculations for future reference
• Share or export results as PDF
• Fully offline — no internet connection required

📐 CALCULATION STANDARDS
Calculations use IEC 60228 resistivity constants (copper 0.01724 Ω·mm²/m, aluminium 0.02825 Ω·mm²/m) with full temperature correction and installation derating factors. Results are cross-checked against ampacity limits so the cable recommended is always safe to carry the load current.

Always verify final designs against your applicable local wiring standard (IEC, NEC, ABYC, BS 7671).

🎯 BUILT FOR PROFESSIONALS
Designed for solar PV installers, marine electricians, off-grid system designers, motorhome and campervan builders, and anyone working with DC electrical systems.

No ads. No accounts. No data collection. Just fast, accurate results.

Recent changes:
Improved display on devices running Android 15 and later
Performance and compatibility improvements for newer Android hardware