Wire Ampacity Calculator

Every wire has a maximum current (amps) it can carry safely. Run too much current and the wire overheats. The NEC requires adjustments for high-temperature areas and bundled wires — both of which reduce how much current a wire can handle. This tool applies those corrections and finds the smallest wire that works for your load.

Tip: If the load runs for 3 hours or more at a time (like HVAC or water heaters), it counts as a continuous load — select Yes to apply the required 125% sizing factor.

NEC table base is 30°C (86°F)

Ampacity Results

Design Load (A)
Min Wire Size
Corrected Amp.
AWG/kcmilTable Amp.Temp CFBundle CFCorrectedOK?

NEC Table 310.16 values used. Minimum conductor size for equipment terminals is typically rated 75°C unless marked otherwise.