What Is Load Factor in Electricity? Formula, Examples, and How It Affects Your Electric Bill
What Is Load Factor
Load factor measures how consistently electricity is used over time by comparing average demand to peak demand during a given period.
Load Factor = Average Demand ÷ Peak Demand
Electric meters record power demand at regular intervals, typically every 15 or 30 minutes depending on the utility. The highest interval recorded during the billing period becomes the peak demand used to calculate demand charges. Load factor compares that peak to the average demand across all recorded intervals.
A higher load factor indicates that electricity demand remains relatively steady throughout the period, while a lower load factor indicates short bursts of high demand compared to typical usage.
Load Factor Formula and How It Is Calculated
Although load factor is defined using average demand, electric bills usually report total energy (kWh) and billing demand (kW). Average demand can therefore be derived from the total energy used during the billing period.
Load factor can be calculated from a bill using three values:
• Total energy used (kWh)
• Billing demand (kW)
• Length of the billing period
In this example, the facility has two meters reporting energy usage:
41,023 kWh
41,423 kWh
Total facility energy
82,446 kWh
The delivery section of the bill shows the billing demand determinant used for charges:
Billing demand
242.57 kW
The billing period runs from July 23 to August 21 (29 days).
29 × 24 = 696 hours
Load factor formula
Load Factor = Total kWh ÷ (Billing kW × Hours)
Calculation
Load Factor = 82,446 ÷ (242.57 × 696)
Load Factor ≈ 0.49
Result
The facility’s load factor for the billing period is about 49%, meaning the average electrical demand was roughly half of the billing demand recorded during the month.
Load Factor Calculator
If you want to estimate load factor quickly, you can use the calculator below. Enter the values from your electric bill and the calculator will apply the load factor formula automatically.
You will need three inputs:
• Total energy used during the billing period (kWh)
• Billing demand shown on the bill (kW)
• Length of the billing period (days)
The calculator converts the billing period to hours and computes average demand and load factor.
LOAD FACTOR CALCULATOR
“Load factor is the relationship between how much power you typically use and the single moment when you use the most.”
What Is a Good Load Factor
There is no single “good” load factor because electricity usage varies widely by facility type.
Facilities that operate continuously tend to have higher load factors because their demand remains relatively stable throughout the day. Facilities with intermittent equipment often have lower load factors because short periods of high demand dominate the overall usage profile.
Typical ranges include:
Industrial operations: 60–90%
Commercial buildings: 30–60%
Highly variable loads: below 30%
A low load factor usually means a facility sets high demand peaks that occur infrequently. In these cases, the site pays for electrical capacity that is only used for short periods.
For example, a small auto shop may operate with a modest average load but occasionally run several high-power machines at the same time. When those loads overlap, they can set the peak demand that determines the demand charge for the entire billing period.
In contrast, a manufacturing facility running production equipment continuously throughout the day tends to have a higher load factor because demand remains relatively consistent.
Why Load Factor Matters for Electricity Costs
Load factor affects electricity costs because demand charges are based on the highest demand recorded during the billing period, not the average level of electricity use.
When a facility has a low load factor, the peak demand used for billing is much higher than the typical level of power consumption. This means the site is paying for electrical capacity that is rarely used.
These peaks often occur when several large loads operate at the same time. If those loads can be scheduled so they do not overlap, the peak demand and the demand charge may be reduced.
Facilities with high load factors tend to have more consistent demand patterns. In these cases there are fewer opportunities to lower demand charges through operational changes.
How to Improve Load Factor
Load factor can improve in two ways.
First, by lowering peak demand.
Second, by increasing average demand.
Only the first approach usually reduces electricity costs.
If a facility averages 4 kW of demand but occasionally spikes to 20 kW, the result will be a low load factor. The objective is not to increase the average demand to match the peak, but to understand what caused the spike.
Interval data makes it possible to analyze these peak events. A peak may be caused by a single piece of equipment, multiple loads operating at the same time, or a temporary operational event.
If several machines contributed to the peak at the same time, adjusting schedules so those loads do not overlap may reduce the demand charge in future billing periods.
Improving load factor is therefore less about increasing electricity use and more about identifying and managing the events that create peak demand.