What gauge should my extension cord be?

Your extension cord gauge depends on amps and length. The working map: 16 gauge for lamps and light duty, 14 gauge for small tools on runs under 50 feet, 12 gauge for saws, compressors, and anything at 100 feet, 10 gauge for space heaters and heavy sustained loads.

Length degrades everything. A 14 gauge cord that is fine at 25 feet is marginal at 100, because voltage drop scales with every foot.

Undersized cords make tools weak and hot, and the cord itself becomes the fire risk when it powers heaters.

When two ratings seem plausible, buy the lower gauge number; nobody has ever regretted a cord that is too capable.

Get the exact answer for your amps and footage from the extension cord calculator.