Wire Gauge Calculator | AWG Wire Size & Voltage Drop

Start in Simple mode with voltage, current, and run length. Heavier loads and longer distances need thicker wire (lower AWG number). Use Safety Review/Advanced modes for installation and environment assumptions.

A common NEC guideline is 3% for branch circuits and 5% combined for feeder + branch. Safety Review mode includes quick 3%/5% targets so you can test both scenarios quickly.

A 20-amp circuit requires a minimum of 12 AWG copper wire (NEC 310.15). For long runs where voltage drop is a concern, you may need to upsize to 10 AWG. Enter your specific amperage and run length in this calculator to confirm the correct size.

Yes. Aluminum wire has about 61% the conductivity of copper, so it requires a larger AWG for the same current capacity. Aluminum is commonly used for service entrance and large feeder circuits. Select your conductor material in Advanced mode for accurate sizing.

Yes! In guest mode, you can export your calculations to JSON format. Sign in is required for PDF and CSV export. Click the export button to download your results. This is perfect for record-keeping, sharing with others, or importing into other tools.

Yes! Your calculation history is automatically saved. Guest users can save up to 50 calculations per workspace locally. Sign in for free to save up to 100 calculations per workspace, with access from any device when logged in.

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