Skip to main content
Calcimator

Electrical Panel Schedule Calculator

Panel load calculation with NEC demand factors for lighting, receptacles, motors, and HVAC.

Inputs

Results

Total demand (VA)

38,750

Total connected (VA)40,000
Demand factor (%)96.9
Demand load amps (A)107.6
Adjusted amps (125%)129.1
Min bus rating (A)150
Bus loading (%)86
Recommended panel spaces12
How to Use This Calculator
  1. Enter the connected lighting, receptacle, motor, and HVAC loads in volt-amperes from your circuit schedule.
  2. Set the panel bus voltage (208 V for 120/208 V systems, 480 V for 277/480 V systems).
  3. Select single-phase (1) or three-phase (3) to match your panel type.
  4. Read the total demand VA after NEC 220 demand factors are applied and the minimum bus rating in amperes.
  5. Check the bus loading percentage and recommended panel spaces to confirm adequate capacity.

How the result changes with HVAC load (VA)

HVAC load (VA)Total demand (VA)
100,000126,750
350,000376,750
650,000676,750
900,000926,750

What each input means

Lighting load (VA)
Total connected lighting load in volt-amperes.
Receptacle load (VA)
Total connected receptacle load in volt-amperes.
Motor load (VA)
Total connected motor load in volt-amperes.
HVAC load (VA)
Total HVAC equipment load in volt-amperes.
Panel voltage (V)
Panel bus voltage (120/208, 277/480 typical).
Phases (1 or 3)
Single-phase (1) or three-phase (3) panel.

What each result means

Total demand (VA)
Total demand load after NEC 220 demand factors applied.
Total connected (VA)
Sum of all connected loads before demand factors.
Demand factor (%)
Ratio of demand load to connected load.
Demand load amps (A)
Total demand load current.
Adjusted amps (125%)
Load adjusted for continuous loads per NEC 215.3.
Min bus rating (A)
Minimum standard panel bus ampere rating.
Bus loading (%)
Percentage of selected bus rating utilized.
Recommended panel spaces
Panel spaces with 25% spare capacity.

How this is calculated

Worked example, using the default values

  1. Identify Input Parameters
    4 parameters
    Lighting load (VA) = 15000, Receptacle load (VA) = 8000, Motor load (VA) = 5000, HVAC load (VA) = 12000 = 6 input(s) provided
  2. Calculate Total demand
    Total demand = lightingDemand + receptacleDemand + motorDemand + hvacDemand
    38750 = 38750
  3. Calculate Total connected
    Total connected = lightingVA + receptacleVA + motorLoadVA + hvacVA
    40000 = 40000
  4. Calculate Demand factor
    96.9 = 96.9

Engine last updated . Checked against 2 independently-derived tests — how we verify calculators.

Related Calculators

The questions that sit next to this one — chosen by subject, including calculators filed under a different category.

Construction Electrical

Electrical Rough-In Labor Calculator

Labor hours and cost per device from device counts, building type, and NECA labor units.

Construction Electrical

Data Cable Calculator

Cable runs, conduit fill per NEC Table 1, and pathway sizing from network drop count.

Electrical & Plumbing

Electrical Load Calculator

Calculate total electrical load by circuit type and determine the service panel size and main breaker needed.

Electrical Engineering

Demand Load Calculator

Calculate residential service demand load per NEC Article 220: general lighting, appliances, HVAC, and service size.

Pool Construction

Pool Electrical Calculator

Circuit requirements for pump, heater, lights, and automation.

More in Construction & Building Trades.