How does the tool balance the legs?

It places each single-pole circuit on whichever leg, A or B, currently carries less load, which greedily keeps the two legs close in total VA. Two-pole 240-volt circuits draw equally from both legs, so half their VA is added to each. The goal is a balanced panel that avoids overloading one bus.

Should I enter load as amps or VA?

Either works. If you enter amps, the tool multiplies by the circuit voltage — 120 V for a single-pole circuit or 240 V for a two-pole — to get volt-amperes. If you know the VA or wattage directly, enter VA. Internally everything is summed in VA so legs and totals are comparable.

Is this connected load or demand load?

It reports connected load — the straight sum of every circuit. The NEC service-load calculation applies demand factors from Article 220 to lighting, small-appliance, range, and other loads, which reduces the figure used to size the service. Apply those demand factors before sizing the main and feeder.

What does the leg amperage tell me?

Each leg's amperage is its VA total divided by 120 volts, representing the line-to-neutral current that bus carries. The higher of the two legs is what must stay under the main breaker rating. A large imbalance suggests moving circuits between legs to even out the load.

Can I use this for a permit drawing?

It produces the circuit-by-circuit schedule electricians reference and submit, but the official service-load calculation must follow NEC Article 220 with the correct demand factors and any local amendments. Treat the output as a working schedule and field reference, then finalize the load calc per code.

What is the Panel Schedule / Load Center Calculator?

Creates a panel schedule with circuit number, description, breaker poles, and connected load in VA and amps; auto-balances circuits across legs A and B; totals each leg; and confirms the main breaker rating is not exceeded for permit and field reference. It runs free in your browser on Gera Tools, with nothing uploaded.

Panel Schedule / Load Center Calculator

Name: Panel Schedule / Load Center Calculator
Creator: Gera Tools
License: https://creativecommons.org/licenses/by/4.0/

Laying out a balanced panel

A breaker panel works best when the load is split evenly between its two legs, so neither bus runs hot while the other sits idle. Building that schedule by hand — numbering circuits, tracking poles, and tallying each leg — is tedious and error-prone. This calculator builds the schedule, assigns circuits to balance the legs, and checks the total against the main breaker.

How it works

Each circuit’s load is converted to volt-amperes. Amps are multiplied by the circuit voltage — 120 V for single-pole, 240 V for two-pole — while VA is used as entered. Single-pole circuits are placed on whichever leg currently carries less load, a greedy balance that keeps legs A and B close. A two-pole 240 V circuit draws from both legs equally, so half its VA lands on each.

Each leg’s current is its VA divided by 120 V (line-to-neutral), and the higher of the two legs is the value that must stay under the main breaker rating. The tool also totals the connected load and shows it as amps at 240 V for a quick service-size sense check.

Example and notes

A 100 A panel with kitchen, lighting, a 40 A range, and a 4500 VA water heater balances the single-pole circuits across legs while the two-pole loads split evenly, and the highest leg stays well under 100 A. Remember this is connected load: apply NEC Article 220 demand factors before sizing the service, and size the main and feeder to the resulting demand load rather than the raw connected total. Local amendments to the NEC may also apply.

Why leg balance matters electrically

A residential 120/240 V service has two ungrounded legs (A and B) each at 120 V to neutral. Single-pole breakers connect to one leg; two-pole breakers straddle both. If all the high-draw circuits — range, dryer, water heater — end up on the same leg, that bus carries far more current than the other. The neutral conductor carries the difference in current between legs: when legs are balanced the neutral is near zero; when legs are badly imbalanced the neutral carries a significant current, which wastes energy and stresses the conductor.

From a practical standpoint, an unbalanced panel also means one leg’s breakers will heat up more than the other’s, shortening their life. Most utility companies recommend legs within 10% of each other.

Connecting the load schedule to the service calculation

The panel schedule output from this tool is the connected load — the sum of all circuits at nameplate. The NEC service calculation under Article 220 applies demand factors that reduce this number before you size the main breaker and meter base. Key demand factors for a dwelling:

Lighting and receptacles (220.42): first 3,000 VA at 100%, next 3,001 to 120,000 VA at 35%, remainder at 25%.
Kitchen small-appliance circuits (220.52): 1,500 VA per circuit at 100% for the first two, then lumped with lighting for demand.
Range (220.55): a 12 kVA range uses an 8 kW demand value from Column C of Table 220.55.
Dryer (220.54): 5,000 W or nameplate rating, whichever is larger.
HVAC (220.60): use the larger of heating or cooling, not both.

After applying demand factors, divide the total demand VA by 240 V to get the minimum service amperage, then round up to the next standard size (100, 125, 150, 200 A etc.). The panel schedule from this tool feeds directly into that calculation as the raw connected total.

Circuit numbering convention

By convention in U.S. panels, circuit 1 is in the top slot of leg A, circuit 2 in the top slot of leg B, then 3/4 below them, and so on alternating down. Odd-numbered circuits are typically on leg A, even-numbered on leg B — though tandem breakers and specific panel layouts can alter this. The calculator assigns circuits to legs A and B by balance rather than strictly by odd/even slot, so the leg assignments shown are for load balancing, not necessarily the physical slot positions in your specific panel model.