Why does panel balancing matter?

On a 120/240 V single-phase system the shared neutral carries only the difference between the two hot legs. Balancing the 120 V loads minimizes neutral current, reduces voltage imbalance between legs, and frees up usable panel capacity so each leg is loaded evenly.

How is the neutral current calculated?

The tool sums the VA on leg A and leg B, converts each to amperes at 120 V, and takes the absolute difference. That difference is the current returning on the shared neutral. When the legs are perfectly balanced the neutral current approaches zero.

Do 240 V circuits affect the balance?

No. A 240 V two-pole circuit draws equal current from both hot legs and its return cancels in the neutral, so it never contributes to imbalance. The tool counts it toward total panel capacity but excludes it from the balance percentage.

What imbalance percentage is acceptable?

A common target is to keep the two legs within about 10% of each other. Beyond that, the heavier leg can approach its capacity while the lighter leg sits idle, and the elevated neutral current and voltage difference can affect sensitive equipment.

How does the rebalancer decide where circuits go?

It sorts the 120 V circuits from largest to smallest and assigns each to whichever leg is currently lighter, a greedy strategy that produces a near-optimal split. It then reports how many circuits would move and the imbalance you would reach.

Single-Phase Panel Load Balancing Calculator

On a 120/240 V single-phase panel the shared neutral carries only the difference between the two hot legs, so spreading the 120 V loads evenly minimizes neutral current and balances the panel. This calculator takes your circuit list, reports per-leg totals and the neutral imbalance, and suggests a reassignment that brings the panel within a 10% balance target.

How it works

Each circuit’s VA is summed by leg, converted to amps, and compared:

leg A amps   = sum of leg-A VA / 120
leg B amps   = sum of leg-B VA / 120
neutral amps = | leg A amps − leg B amps |
imbalance %  = | leg A VA − leg B VA | / max(leg A VA, leg B VA) × 100

A 240 V two-pole circuit loads both legs equally and cancels in the neutral, so it is excluded from the imbalance figure. The rebalancer sorts the 120 V circuits largest-first and drops each onto the lighter leg, which closely approaches the best possible split.

Example and tips

Suppose leg A carries 5000 VA and leg B carries 3000 VA. Leg A draws about 41.7 A, leg B about 25 A, so the neutral carries roughly 16.7 A and the panel is (5000 − 3000) / 5000 = 40% out of balance. Moving a 1000 VA circuit from A to B brings the legs to 4000 and 4000, dropping the neutral current to near zero. Tips: balance by running load rather than breaker count, since a single large circuit can outweigh several small ones; keep 240 V loads in the list for capacity even though they do not affect balance; and rebalance again after adding any large new circuit such as an EV charger or electric range.