Wire Size Calculator
Estimate a minimum AWG conductor size from voltage-drop criteria for copper or aluminum circuits.
Turn this result into a calculation record
Carry the tool context into the PROFENG calculation-check and record workspace without implying certification or engineering approval.
Formula source and acknowledgement
Source being confirmed. PROFENG has not yet approved a published source for this exact calculator implementation, so no candidate book, paper or standard title is displayed here.
Credit for any underlying published method belongs to its original author(s) or standards body. PROFENG presents its own implementation and wording and does not imply endorsement or affiliation.
Read the PROFENG methodology for formula sourcing and automated checks →
Why use this wire size calculator?
Wire Size Calculator selects the smallest listed AWG that satisfies the entered voltage-drop target using a circular-mil calculation.
Example
Enter voltage, current, one-way run length and a 3% drop target to get a voltage-drop-based AWG estimate.
Important note
The result is not a complete conductor-size determination. Ampacity, derating, fault protection, insulation and code requirements may require a larger conductor.
How to use it
Start with the inputs shown above, review the assumptions or options, then generate the result. Where the tool creates a file, keep the original until you have opened and checked the downloaded output.
Frequently asked questions
Is Wire Size Calculator free?
Yes. The core tool is free to use without creating an account.
Do I need an account to use Wire Size Calculator?
No. You can use the core Toolbox workflow without signing up.
Does Wire Size Calculator work on mobile?
Yes. Toolbox is designed for modern mobile and desktop browsers, although complex file workflows can be easier on a larger screen.
QA, changelog and corrections
Last QA update: 30 September 2026.
This page is covered by publication and metadata QA only unless a tool-specific automated verification status is displayed above. No named-expert review is claimed.
Changelog
30 September 2026 – source/indexation status, metadata and correction pathway reviewed. Engineering tools display the automated verification label only when they are inside the passing Part 3 verification scope.