Free interactive tools built for fire alarm technicians. All calculations run right in your browser — giving you instant results with no sign-up required.
Calculate voltage, current, resistance, and power. Enter any two values and solve the rest instantly.
Calculate required battery AH capacity for fire alarm systems with NFPA 72 standby and alarm duration support.
Add devices to calculate total standby and alarm current draw, then feed results into battery sizing.
Calculate voltage at each device on a NAC or speaker circuit with pass/fail indicators.
Read resistor color bands or reverse-lookup by value with fire alarm EOL presets.
Use a visual DIP switch bank with binary, decimal, hex conversion, and fire alarm panel presets.
Calculate conduit fill percentage with NEC thresholds and common fire alarm wire types.
Reference AWG ampacity, correction factors, and common fire alarm wire applications.
Calculate sound level at distance for fire alarm speaker and horn coverage planning.
