Demand Factor Calculator

Apply NEC demand factors to convert connected load to demand load.

About Demand Factors

Connected Load: Sum of all nameplate ratings of equipment that could potentially operate.

Demand Load: Portion of connected load expected to operate simultaneously.

Demand Factor: Ratio of demand load to connected load (always 100% or less).

NEC Demand Factor Tables

Table 220.42 - General Lighting

Type of Occupancy Portion of Load Demand Factor
Dwelling UnitsFirst 3000 VA100%
3001 to 120,000 VA35%
Over 120,000 VA25%
HospitalsFirst 50,000 VA40%
Remainder20%
Hotels/MotelsFirst 20,000 VA50%
Remainder40%
WarehousesFirst 12,500 VA100%
Remainder50%
All OthersTotal100%

Table 220.54 - Electric Dryers

Number of Dryers Demand Factor (%)
1-4100%
585%
675%
765%
860%
955%
1050%
11-1345%
14-1940%
20-2435%
25-2932.5%
30-3430%
35-3927.5%
40+25%