Electricity Usage and Measurement
Electrical Demand Charge Calculator
Use Electrical Demand Charge when demand charge is the quantity you need. Enter billing demand and demand rate, then compare the answer with the equipment or operating limits that apply to your case.
Calculate Demand charge
Check the source and units before calculating.
Compare two operating cases
Change Billing demand from 75 kW to 90 kW while preserving the other measurements. The output changes from 1,350.00 $ to 1,620.00 $.
Use a separate scenario when multiple conditions change together.
Formula used on this page
Here, Demand charge is obtained from charge = billing demand × rate. The formula draws on Billing demand and Demand rate.
The initial scenario returns 1,350.00 $. Re-enter field data before using the answer in a design or comparison.
Calculate demand charge from billing demand and demand rate. For the companion electricity charge calculation, open Electricity Tariff Calculator.
Input notes
Separate real power, apparent power, energy, and demand before entering values. Nameplate and meter values are not interchangeable unless they describe the same condition.
Use the displayed unit for every field and document conversions separately. The broader analysis may also use Battery C-Rate Calculator.
- Billing demand
- Default example: 75 kW. Enter billing demand in kW.
- Demand rate
- Default example: 18 $/kW. Enter demand rate in $/kW.
How to use the result
Interpret Demand charge on the same basis used for the source values. Compare it with the relevant tariff and measured load profile.
Save the raw entries before testing another scenario. If you also need coincidence factor, continue with Electrical Coincidence Factor Calculator.
Using the answer downstream
Record billing demand and demand rate with demand charge. Include the operating state and data source.
Transfer demand charge before applying any display rounding. Round at the final reporting step.
Assumptions and limitations
The utility may apply ratchets or seasonal rules.
Outside the entered variables, consider idle consumption, load variability, tariff changes, and maintenance downtime. Document which effects were checked elsewhere in the analysis.
Separate real power, apparent power, energy, and demand before entering values. Pair this page with Electrical Load Factor Calculator when reviewing load factor.
Questions about inputs and assumptions
What else is required before final selection?
Use the number as one check, then review billing rules, meter data, demand intervals, and operating schedules.
What precision should move to the next worksheet?
Retain the raw result for comparison and create a separately rounded reporting value if needed.
Can an input legitimately be zero?
Use zero only when it describes the physical condition. It is not a substitute for missing data.
What data should go into Electrical Demand Charge?
Choose entries that describe the same case. Separate real power, apparent power, energy, and demand before entering values.
What should I verify beyond the displayed inputs?
The utility may apply ratchets or seasonal rules. Also consider fixed charges, demand ratchets, seasonal rates, uncertainty, and future load change.
Why might measured demand charge differ?
First confirm that the measurements match the equation. Then review fixed charges, demand ratchets, seasonal rates, uncertainty, and future load change.