Wire Size Calculator
Minimum cable cross-section for an allowed voltage drop.
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How it works
Minimum area = k × resistivity × length × current ÷ (supply voltage × allowed drop). The result is rounded up to the next common metric cable size. This checks voltage drop only; the cable must also be rated for the current (ampacity) and the installation method. Example: with the default values, minimum cross-section comes to 5.07 mm².
FAQ
Is this calculator free?
Yes. No signup is needed and nothing you enter is stored.
Is the result exact?
Results are rounded for display. For financial, medical, or legal decisions, confirm with a professional.
Do my numbers leave my device?
No. The calculation runs in your browser.