Electrical panel load calculator
A 2,000 sq ft home with the default kitchen and laundry circuits comes to 5,625 VA after demand factors, which at 240 V points to a 60 A main panel. Add fixed appliances, an electric range, a dryer and heating or cooling to size the service. Free in your browser.
- Free
- Runs in your browser
- No sign-up
- Your data stays on your device
Run — free
Worked example
- Sq ft
- 2,000
- Service volts
- 240 VA
- Va per sqft
- 3
- Small appliance circuits
- 2
- Laundry circuits
- 1
Choosing a main service panel starts with a load estimate: how many volt-amperes does the dwelling demand under planning rules, and what ampere rating covers that total at the service voltage? This electrical panel load calculator combines general lighting from floor area, kitchen small-appliance and laundry circuit allowances, optional fixed-appliance nameplates with a multi-appliance demand factor, plus range, dryer, and HVAC loads. It applies a dwelling-style demand curve to the general lighting group, sums the remaining loads, converts total calculated volt-amperes into service amperes, and recommends the next common main-breaker size with headroom. Results are planning estimates for early design, renovation budgeting, and education—not a substitute for a licensed electrician’s final calculation under the adopted electrical code.
How dwelling service load is built from circuits and demand factors
Residential service sizing usually begins with a general lighting load proportional to floor area, commonly three volt-amperes per square foot of dwelling space. That lighting total is grouped with fixed allowances for kitchen small-appliance branch circuits and laundry circuits—each counted at one thousand five hundred volt-amperes—because those circuits are treated as part of the general load for demand purposes rather than as independent nameplate machines.
The combined general group is then reduced with a stepped demand curve: the first three thousand volt-amperes at one hundred percent, the next band through one hundred twenty thousand at thirty-five percent, and any remainder above that band at twenty-five percent. Fixed appliances such as water heaters, dishwashers, and disposals are entered as a nameplate sum; when four or more such appliances are included, a seventy-five percent demand factor is applied to that sum, reflecting the low probability that every fixed load runs at full nameplate together.
Electric range, dryer, and the controlling heating or cooling load are added at the volt-ampere values you supply, typically nameplate or equipment schedule figures. The sum of demand-adjusted general load, demand-adjusted fixed appliances, and the three specialty adders is the total calculated volt-ampere load used for service sizing.
Dividing by the service voltage—two hundred forty volts for a typical single-phase dwelling—yields calculated amperes, which are then matched to the next standard panel size such as one hundred, one hundred twenty-five, one hundred fifty, or two hundred amperes so the recommended main breaker is never smaller than the estimate.
Where teams use a panel load calculator and how pricing works
Builders and electrical estimators use a panel load calculator when a schematic design package needs a credible main service size before every receptacle and special circuit is finalized. Multifamily product managers store deterministic totals next to unit type and square footage so bids share one formula across seasons. Homeowners planning an electric range, dryer, or heat-pump addition can estimate whether the existing service amperage is likely tight before calling a contractor.
The interactive tool above runs free in the browser for interactive checks. Source inputs and outputs are retained only for the platform retention window and are never used to train models. Always have a qualified professional confirm final service equipment under the electrical code adopted in your jurisdiction.
What you can do with it
New-home service and panel takeoffs
Turn floor area plus range, dryer, HVAC, and fixed appliances into total calculated VA, service amperes, and a recommended main panel size for early electrical bids.
Panel upgrade and electrification checks
Estimate whether adding heat pumps, an induction range, or an electric dryer pushes a dwelling past a 100 A or 150 A service under planning demand factors.
Estimator dashboards and unit-type libraries
Store deterministic panel recommendations next to unit square footage so multifamily or production-home types share one load formula across bids.
FAQ
Is this the same as a licensed NEC service calculation?
No. It is a transparent planning estimate inspired by common dwelling demand factors. Final service equipment must follow the adopted electrical code and a qualified electrician or engineer.
What panel sizes can it recommend?
It picks the smallest standard size at or above calculated amperes from 60, 100, 125, 150, 200, 225, 320, 400, and 600 A. Above 600 A it rounds up to the next 100 A step.
How is the general lighting load calculated?
The floor area is multiplied by 3 VA per square foot, and each kitchen small-appliance circuit and laundry circuit adds 1,500 VA. That group is then reduced in steps: the first 3,000 VA count in full, the next band up to 120,000 VA at 35%, and anything above at 25%.
When does the 75% demand factor for appliances apply?
When you include four or more fixed appliances, such as a water heater, dishwasher or disposal, their combined nameplate load is counted at 75%. With fewer, the full sum is used. The range, the dryer and the heating or cooling load are added separately at the values you enter.
What should I enter for gas appliances and for heating or cooling?
Leave the range and dryer at zero when they are gas-fired or absent. For heating and cooling, enter only the larger of the two loads in VA, because one system usually controls the service. Use nameplate or equipment schedule figures for each.
Related tools
For developers — API access
Everything on this page is available programmatically. This section is for teams who want to wire it into their own systems; everyone else can just use the tool above.
API endpoint
Prefer to automate it? One authenticated POST creates the task; the result comes back by webhook or a signed link. The same capability also runs here on the web, by email and from Telegram — and soon from our app too.
Call it from your stack
curl -X POST https://api.kit.forhosting.com/home/panel-load \
-H "Authorization: Bearer $KIT_KEY" \
-H "Content-Type: application/json" \
-d '{"sq_ft":2000}'const res = await fetch("https://api.kit.forhosting.com/home/panel-load", {
method: "POST",
headers: {
"Authorization": `Bearer ${process.env.KIT_KEY}`,
"Content-Type": "application/json"
},
body: JSON.stringify({
"sq_ft": 2000
})
});
const { task_id } = await res.json();import os, requests
res = requests.post(
"https://api.kit.forhosting.com/home/panel-load",
headers={"Authorization": f"Bearer {os.environ['KIT_KEY']}"},
json={
"sq_ft": 2000
},
)
task_id = res.json()["task_id"]<?php
$res = file_get_contents("https://api.kit.forhosting.com/home/panel-load", false, stream_context_create([
"http" => [
"method" => "POST",
"header" => "Authorization: Bearer " . getenv("KIT_KEY") . "\r\nContent-Type: application/json",
"content" => '{"sq_ft":2000}',
],
]));
$task = json_decode($res, true);body := bytes.NewBufferString(`{"sq_ft":2000}`)
req, _ := http.NewRequest("POST", "https://api.kit.forhosting.com/home/panel-load", body)
req.Header.Set("Authorization", "Bearer "+os.Getenv("KIT_KEY"))
req.Header.Set("Content-Type", "application/json")
res, _ := http.DefaultClient.Do(req)Example request
{
"sq_ft": 2000
}Example response
{
"task_id": "tsk_a1b2c3d4e5f6a1b2c3d4e5f6",
"type": "home.panel_load",
"status": "queued",
"_links": {
"result": "/tasks/tsk_…/result"
}
}The API is asynchronous: the call returns a task_id immediately and the result arrives by webhook. Polling is capped at 1 req/s per task.
Pricing
Published price — no tokens, no invented credits. A failed task is never charged.
Errors
| HTTP | Code | Meaning |
|---|---|---|
401 | unauthorized | Missing or invalid API key. |
402 | insufficient_balance | Your balance doesn't cover the task price. |
404 | unknown_type | That task type doesn't exist. |
429 | rate_limited | Too many requests. Use the webhook instead of polling. |
Technical notes
The same pure arithmetic powers the free browser tool and the API, so interactive checks and automated takeoffs never disagree.
Input fields, response shape, and validation rules
Square footage, service voltage, and unit load must be strictly greater than zero; circuit counts and appliance count must be non-negative integers; range, dryer, HVAC, and fixed appliance volt-amperes must be zero or greater. Convert square meters to square feet before calling if your plans use metric area, and enter HVAC as the larger of heating or cooling when only one space-conditioning system will dominate the service. Required input is sq_ft, the dwelling floor area in square feet used for the lighting unit load. Optional service_volts defaults to two hundred forty; va_per_sqft defaults to three; small_appliance_circuits defaults to two; laundry_circuits defaults to one. Optional fixed_appliances_va and fixed_appliance_count describe other fixed loads and whether the multi-appliance seventy-five percent factor applies. Optional range_va, dryer_va, and hvac_va default to zero when equipment is gas-fired or absent. Aliases such as square_feet, sqft, volts, unit_load, sa_circuits, appliances_va, and ac_va are accepted so forms and scripts are not locked to a single spelling. On success the response echoes the inputs used, then returns general_lighting_va, small_appliance_va, laundry_va, base_va before demand, general_demand_va after the stepped curve, fixed_demand_factor and fixed_demand_va, total_calculated_va, calculated_amps, recommended_panel_amps, headroom_amps, and headroom_percent so you can show both the raw demand and the catalog panel size. Missing or non-numeric required fields and out-of-range values fail with invalid_input and are not billed. There is no network lookup and no model inference—the same JSON always produces the same result.
Where teams use a panel load calculator and how pricing works
Remodelers comparing a one-hundred-ampere panel upgrade against a two-hundred-ampere service can change floor area and appliance nameplates and see how calculated amperes and recommended_panel_amps move without rebuilding a spreadsheet. Educators demonstrate demand factors by toggling fixed_appliance_count across the four-appliance threshold while holding nameplate sum fixed, or by scaling sq_ft alone to show how general lighting demand grows slower than raw area. Programmatic calls use the ForHosting KIT prepaid balance at $0.002 per successful request, with no subscription and no charge when validation fails. Because the arithmetic is tiny and fully local to the Worker, latency is dominated by the task queue handshake rather than by computation, which makes the capability suitable for high-frequency form validation as well as batch reprocessing of historical plan tables.
Technical questions
What formula does this electrical panel load calculator use?
general lighting = sq_ft × va_per_sqft; add 1500 VA per small-appliance and laundry circuit; apply dwelling general demand (first 3000 VA at 100%, next through 120000 at 35%, remainder at 25%); add fixed appliances (75% if count ≥ 4), range, dryer, and HVAC; amps = total VA ÷ service_volts; panel = next standard size.
What happens if sq_ft is zero or negative?
The request fails with invalid_input and is not charged. sq_ft must be a finite number strictly greater than zero.
Is the electrical panel load calculator free?
The browser tool is free. API calls cost $0.002 per successful request from your prepaid KIT balance; failed validation is never charged.