Load Factor Calculator: How to Calculate It
Free load factor calculator for electricity. See the formula and how to calculate load factor from two numbers on your bill: total kWh and peak kW. Get your percentage and what your usage shape means, all in your browser.
The calculator above gives you your electricity load factor from two numbers that are already printed on your bill: the total kWh you used and the peak kW on your demand line. Enter them with the length of the billing period and you get your load factor as a percentage, along with the average demand behind it. Everything computes in your browser. Nothing uploads, nothing is stored, and nothing is for sale.
This page is about load factor for electricity. The same phrase means something different in aviation and in finance; if you are looking for seat occupancy or debt ratios, this is not that.
What is load factor in electricity?
Load factor is the ratio of average demand to peak demand over a period, written as a percentage. Average demand is the energy you used spread evenly across every hour of the period; peak demand is the single highest interval your meter recorded. A load factor near 100 percent describes an account that runs close to its peak around the clock. A low load factor describes one that spikes well above how it normally runs. It is a plain description of the shape of your usage, and it is the electrical meaning of the term.
The load factor formula
Load factor is average demand divided by peak demand over a period. From a bill, that works out to:
Load Factor = kWh used / (Peak kW x hours in the period)
The numerator is the energy you actually used. The denominator is the energy you would have used if you had run at your single worst interval for every hour of the period. So the percentage answers a plain question: how close does your normal operation come to your peak?
How to calculate load factor
Three numbers give you the result. Take the kWh you used in the billing period, divide it by your peak kW multiplied by the number of hours in the period, and read the answer as a percentage. Worked through: a facility that used 41,000 kWh in a 30 day period, which is 720 hours, with a 137 kW peak has a load factor of 41,000 / (137 x 720), which is about 42 percent. The calculator above does this arithmetic for you; the steps are here so you can see exactly what it is doing.
What your load factor tells you
Load factor is the shape of your usage compressed into one number, and shape is what a commercial electricity bill actually prices. Utilities bill delivery on your single highest interval, the peak demand, not on your average. Two facilities using identical kWh can pay very different delivery costs because one runs flat and the other spikes.
A high load factor means you run steady: your peak is close to your everyday level, and the demand charge it sets is spread across many kWh. A low load factor means your usage is concentrated: a short interval sits far above how you normally operate, and a meaningful share of your delivery cost rides on that one moment. Neither number is good or bad by itself. A bakery with morning ovens and a machine shop with staggered shifts have different shapes for real operational reasons. The number tells you what your shape is; whether that shape is worth changing is a separate question the number alone cannot answer.
Where to find the two numbers
Both come off one bill. The kWh is the total usage for the period, usually front and center. The peak kW is on the demand line: on a ComEd commercial bill it is the billed demand your Distribution Facilities Charge is computed from. The service period dates give you the day count. Use the same bill for both numbers; mixing a peak from one month with kWh from another produces a number that describes nothing.
If you want to see the shape behind the number rather than just the ratio, our interval data analysis tool reads your meter's own interval export and draws the full load profile, including the always-on floor your load factor summarizes away.
How do you calculate load factor?
Divide the kWh used in a billing period by the peak demand in kW multiplied by the hours in the period. The result is average demand as a share of peak demand, expressed as a percentage. The calculator above does exactly this arithmetic, nothing more.
What is a good load factor for electricity?
There is no universal good number, because load factor reflects what a facility does. Steady operations like cold storage often run above 70 percent; single shift operations with big startup loads can sit under 30 percent. What matters is that a low number means your delivery cost concentrates on a few peak intervals, and a high number means it spreads across your whole month.
Why is my load factor low?
A low load factor means your highest interval sits far above your average draw. Common structural causes are equipment that starts together, short heavy processes, or a facility that runs hard for part of the day and nearly idles the rest. Interval data shows which of these produced your specific peak; the ratio alone cannot.
Does a higher load factor lower my bill?
Not by itself, and this calculator will not tell you to chase one. The demand charge is set by your peak kW, so the same peak with more kWh behind it produces a higher load factor and a bigger total bill. Load factor describes how your existing cost is structured; it is not a dial to turn.
Is this the same load factor as in aviation or finance?
No. Airlines use load factor for filled seats and lenders use it for debt service. This page is the electrical one: average demand over peak demand.