Fire Alarm Calculators
Tap a button to open a calculator. Only one opens at a time to keep the page clean.
Ground Fault Diagnostic
Simulate expected meter readings for a ground fault, or diagnose fault side and approximate leakage from real measurements.
Resistor Selector
Find the nearest standard value (E-series), or compute R from voltage/current (Ohm’s law) or LED parameters. Shows color bands and estimated wattage.
Battery Sizing (Standby + Alarm)
Estimate amp-hours for a 24V panel (two 12V batteries in series).
Voltage Drop
Two-wire loop: round-trip length, Ω/1000ft per gauge.
Wire Gauge Selector
Suggest minimum AWG to meet a % drop target.
NAC Load Planner
Sum device currents and compare to a circuit capacity.
| Description | Per-device (mA) | Qty |
|---|
Speaker / Amplifier Load
Sum speaker taps and compare to amplifier capacity.
| Location / note | Tap (W) | Qty |
|---|
Compressor Wire Size Selector
Select minimum Cu AWG to satisfy ampacity (× factor) and voltage-drop limits.
DIP Switch Address Helper
Build or decode DIP positions as a binary value. State persists in this browser.
Occupant Load NFPA 101–style
Pick a use group & subtype to auto-fill a factor from your local JSON library, or enter a factor directly.
/resources/calculators/occupant-load-factors.json. Mixed uses: calculate separately then sum. Fractions usually round up; confirm with your edition/AHJ.
Optional: Egress capacity check
Enter capacity factors used by your jurisdiction (stairs vs. level components).
Conduit Fill Calculator
NEC Chapter 9 — Table 1 and Table 4 referenceUp to 40% fill for more than 2 conductors