Electricity Demand Charge Calculator
Estimate the demand charge component of your electricity bill based on your peak kW demand and your network's demand tariff rate.
Your results
Calculation breakdown
- Demand charge
- Demand charge = peak demand (kW) × demand rate ($/kW/month)
- Total
- Total = demand charge + (usage kWh × usage rate)
Worked example
A peak demand of 5 kW at $15/kW/month adds $75, plus 500 kWh at 25c/kWh adds $125, giving an estimated monthly total of $200.
Assumptions
- Demand tariff structures vary between networks; some measure demand over a 30-minute window and others differently.
- Excludes daily supply charge.
- Reducing simultaneous appliance use can lower peak demand and this charge.
How this calculator works
Enter your measured peak demand in kW (from your smart meter or bill) and your demand tariff rate per kW to estimate the demand charge portion of your bill, then add it to your usage charge for a total estimate. Demand tariffs are increasingly common for both households and small businesses with solar.
Frequently asked questions
Where do I find my peak demand?
It is shown on bills using a demand tariff, or can be checked via your smart meter portal, usually as the highest average kW over a short window.
Why do I have a demand charge as a solar owner?
Networks are shifting more households with solar onto demand tariffs because your peak import demand still stresses the grid even if annual usage is low.
Can I reduce my demand charge?
Yes, spreading high-draw appliances like ovens, EV chargers and air conditioners across different times can lower your peak demand reading.
Actual prices, usage, efficiency and savings vary by provider, equipment, location and behaviour.