EleCalculator

Residential Electrical calculator

Electrical Panel Load Calculator

This electrical panel load calculator starts with the capacity question: a 200A, 120/240V panel reaches the practical 80% planning threshold at 160A, so new continuous additions get tight when the calculated load is already near that point. In the modeled all-electric home example, the panel screens at about 140.9A, 70.5% utilization, and 19.1A of headroom below 160A. Residential modes apply a dwelling-style general-load reduction, while commercial modes stay conservative and treat entered loads as connected values unless project-specific demand numbers are already known.

Updated June 14, 2026

A 200A 120/240V panel is usually considered tight for new continuous additions once the calculated load current is already above about 160A, because that is 80% of the panel rating; the same screen also helps review a loaded subpanel before adding another feeder or EV circuit.

160A on a 200A panel = 80% utilization, leaving little headroom for EV charging or other long-duration loads; a smaller subpanel can hit the same problem sooner.

Enter panel rating, voltage, and major loads below to estimate panel current, utilization, spare amps, and 80% planning headroom

Calculator Inputs

Field notes

Calculation Results

Enter values above to see calculation results

Field kit

Tools for panel load notes

Turn the load estimate into a measured site note with tools suited to current checks and panel documentation.

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Calculation history

Example Calculations

200A residential main panel

Review a common all-electric home panel with range, dryer, water heater, and HVAC.

Inputs
  • Panel Type: Residential main panel
  • Panel Voltage: 120/240V single-phase
  • Panel Rating: 200
  • General Lighting: 8000
  • Small Appliance Circuits: 2
  • Laundry Circuits: 1
  • Range Load: 12
  • Dryer Load: 5
  • Water-Heater Load: 4.5
  • Hvac Load: 8
  • Other Loads: 2

100A condo subpanel

Check a dwelling-unit subpanel on a 120/208V building service.

Inputs
  • Panel Type: Residential subpanel
  • Panel Voltage: 120/208V three-phase
  • Panel Rating: 100
  • General Lighting: 3500
  • Small Appliance Circuits: 2
  • Laundry Circuits: 1
  • Range Load: 8
  • Hvac Load: 3
  • Other Loads: 1

How to Use

How to use the electrical panel load calculator

  1. Select the panel type and the panel voltage.
  2. Enter the panel rating in amperes.
  3. Enter the connected lighting or receptacle load already assigned to that panel.
  4. For residential panels, add any small-appliance circuits, laundry circuits, household range, and dryer loads that are actually on the panel.
  5. Enter the water heater, controlling HVAC load, aggregate motor loads, and other fixed loads.
  6. Review the calculated load current, panel utilization, spare capacity, and the 80% planning headroom.

What the key results mean

  • Calculated Load Current is the estimated amperage on the selected panel voltage.
  • Panel Utilization shows how much of the panel rating is already being used.
  • Spare Capacity shows the remaining amperes below the panel rating.
  • 80% Planning Headroom is a practical screen for future continuous loads such as EV charging or long-run HVAC equipment.

Reference checks built into the panel screen

Screen Modeled Basis How to read it
Residential general load 100% first 3 kVA, 35% remainder Only used for residential panel modes and only on the general load portion.
Household range 8 kW up to 12 kW Applies only to the single-household range screen modeled here.
Household dryer Nameplate or 5 kW minimum Used only in residential panel modes.
Commercial panel mode Connected load at 100% Keeps the screen conservative when occupancy-specific demand tables are not modeled.
Continuous-load planning 80% of panel rating Useful for deciding whether a panel still has room for new long-duration loads.

This calculator is intentionally a panel-capacity screen, not a full project schedule package. It does not assign branch spaces, phase-balance individual circuits, or calculate separate largest-motor adders. Use it to see whether the entered loads are reasonable for the panel you have in mind, then move to conductor, breaker, and full project documentation tools as needed.

Start with the Residential Load Calculator when the open question is the whole dwelling service: Residential Load Calculator. Use this page after the service-load assumptions are known and the question becomes panel utilization, spare amperes, or 80% planning headroom. For a next-service-size screen, use the Electrical Service Size Calculator. For conductor review, use the Wire Size Calculator. Move to the Breaker Sizing Calculator only after the branch or feeder load basis is known; move to the Short Circuit Calculator when the next question is interrupting rating, SCCR, or available fault current.

When the next step is documenting an added EV charger, HVAC load, or other continuous addition against the remaining headroom, use the Panel Spare Capacity Load Addition Worksheet to record the existing load, proposed load, 80% planning margin, service capacity, and closeout status.

Common Applications

Checking whether a 100A, 125A, 200A, or 225A panel still has usable headroom

Reviewing subpanel loading before adding EV charging, HVAC, or shop equipment

Comparing 120/240V and 120/208V residential panel loading

Screening small commercial panelboards before a tenant improvement or equipment addition

Documenting whether a panel is already near or above the 80% planning threshold

Frequently Asked Questions

Is this the same as a full panel schedule calculation?
No. This tool screens panel current, utilization, and spare capacity from the loads you enter. It does not build a full panel schedule, assign circuit positions, or phase-balance individual branch circuits.
Why does the calculator show an 80% planning threshold?
The 80% threshold is a practical screen for panels that may serve new continuous loads. It helps you see whether there is still comfortable headroom for additions such as EV charging, ventilation, or other equipment that can run for long periods.
Can I use the commercial mode for a permit-level load study?
Not by itself. Commercial mode is conservative because it keeps entered loads at 100% connected value unless you already entered project-specific demand numbers. Permit-level studies still require the correct occupancy method, load counts, and project documentation.
Why does the motor warning say the largest motor is not modeled separately?
The calculator accepts motor load as one aggregate running-load number. That is useful for a quick screen, but it does not break out the largest motor for a separate feeder adder. If motors govern the project, review that portion separately.

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