Fuse Sizing Calculator

Calculate proper fuse rating based on load current, NEC guidelines, and I²t coordination.

Normal operating current of the circuit.
A
Peak inrush current on startup.
A
Duration of inrush current.
ms
Operating ambient temperature.
°C

Results

Min Fuse Rating (125%)-A
Inrush I²t-A²s
Derating Factor-
References: NEC Article 240; IEC 60269; Littelfuse Fuseology Guide