Time-of-Use Electricity Calculator
Compare flat, peak and off-peak electricity rates to estimate how shifting appliance use could affect your daily, monthly and annual energy costs.
Don't know your TOU rates?
Quick guide to finding your exact Peak and Off-Peak electricity tariffs
- 1Check Utility BillExamine the detailed breakdown charges section on your latest monthly electricity bill.
- 2Online Portal / AppLog into your energy provider's official website or mobile app under Tariff or Plan Details.
- 3Identify Peak HoursLocate the exact rate charged during Peak (high cost) and Off-Peak (discounted cost) hours.
- 4Check Tariff TypeIf your utility charges a single flat rate all day without TOU options, stay on your flat rate.
Estimate Your Time-of-Use Savings
Fill in your current flat electricity rate along with your utility's Peak and Off-Peak tariffs above to unlock your exact annual dollar and energy savings.
Estimated Results
Enter details and click "Calculate Cost" to see personalized cost insights here.
What do these savings mean?
How the Time-of-Use Electricity Calculator Works
This time of use electricity calculator helps you estimate the difference between a standard single-rate tariff and a time of use electricity plan. By inputting your local electricity rates, the tool automatically calculates the potential savings or extra costs associated with running heavy household appliances.
The underlying logic uses a formula-based estimate to determine the cost for each period. The energy used by the appliance is multiplied by the rate for that period. It specifically compares the cost of running the selected appliance at the flat, peak and off-peak rates. The calculator then scales these results to show your estimated daily, monthly and annual appliance electricity cost under TOU rates. To evaluate overall household efficiency, you can also Analyse Household Electricity Usage.
What Is Time-of-Use Electricity?
Time-of-use electricity pricing is a tariff structure where providers charge different electricity prices depending on when the electricity is consumed. Instead of paying one standard rate all day, your electricity costs fluctuate based on grid demand.
When you subscribe to a time of use electricity plan, your utility provider assigns specific hours for peak grid demand, and separate hours for off-peak grid demand. Providers define their own periods and rates, which often encourages households to shift flexible usage away from the most expensive periods.
Peak and Off-Peak Rates
The most common time-varying tariffs divide the day into two primary periods: peak and off-peak.
- Peak Rate: The highest price per kilowatt-hour, typically occurring in the late afternoon and early evening when residential electricity demand is highest.
- Off-Peak Rate: The lowest price per kilowatt-hour, usually applying overnight and during the middle of the day when overall demand is lower or renewable energy is abundant.
Remember that these rate periods may vary by provider, season, weekday or weekend, location, and even public holidays. Always check your specific tariff version to confirm the hours that apply to your home.
How to Calculate Time-of-Use Appliance Electricity Cost
This calculator compares the cost of running the same appliance under a flat electricity rate, a peak rate and an off-peak rate. It does not divide household consumption across multiple rate periods or calculate a complete utility bill.
- Calculate appliance energy use:
Energy used in kWh = Watts × Operating hours ÷ 1,000. (Need to convert watts to kilowatts first? Use our converter.) - Calculate the flat-rate cost:
Energy used × Flat electricity rate - Calculate the peak-rate cost:
Energy used × Peak electricity rate - Calculate the off-peak cost:
Energy used × Off-peak electricity rate - Compare the flat-rate cost with the off-peak cost to estimate the potential savings or additional cost from changing when the appliance is used.
Results are scaled to daily, monthly and annual estimates based on the usage details entered.
If you want to estimate the cost of a single appliance without time-varying rates, you can Calculate Appliance Electricity Cost directly.
Flat Rate vs Time-of-Use Electricity
When choosing an electricity plan, you must often decide between a flat rate and a time-of-use rate. A flat or single rate means the same usage rate generally applies regardless of the time of day, subject to the actual plan’s terms and conditions.
A time-of-use rate means different prices apply during different rate periods. To properly compare a flat rate versus a time-of-use rate, the comparison must use the exact same total kWh. It is important to note that a TOU plan is not always cheaper. If a large portion of your electricity consumption occurs during peak hours, your estimated appliance electricity cost under TOU rates may actually be higher than it would be on a standard flat rate.
Is Time-of-Use Electricity Worth It?
Whether time of use electricity is worth it depends entirely on your household habits and the appliances you use. To determine if time of use is right for you, consider how much of your daily usage occurs during peak periods and the price difference between the rate periods.
Using a time of use savings calculator helps you visualise how much usage is flexible. You also need to factor in provider-specific rules, fixed charges, and seasonal schedules. If you can successfully shift a large portion of your flexible usage away from peak periods, you may see substantial savings. If your usage is rigidly fixed during the late afternoon, you may be better off sticking with a standard flat rate.
Appliances and Usage That May Be Shifted Off-Peak
Shifting flexible electricity usage to off-peak hours is the primary way to benefit from a time-of-use tariff. Some common appliances and systems that may be shifted include:
- EV charging: EV charging can be one of the largest flexible household electricity loads, making it highly beneficial to charge overnight. You can estimate this using an EV Charging Cost Calculator.
- Home-battery charging: Charging a battery off-peak and discharging it during peak hours.
- Electric water heating: Heating water overnight to use the following morning.
- Pool pumps: Running heavy circulation pumps during discounted periods.
- Selected heating or cooling pre-conditioning: Pre-heating or pre-cooling a home before peak hours begin. You can Compare Heat Pump and Gas Costs to understand those implications.
- Washing machines, clothes dryers, and dishwashers: Delaying cycles until the peak period ends.
Always ensure you consider safety, comfort, noise, manufacturer instructions, and provider schedules when shifting appliance usage. For homes relying on backup systems during outages, a Backup Power Calculator can help estimate required energy capacities. You can also explore a Solar ROI Calculator to see if generating your own power may reduce the amount of peak-priced electricity purchased from the grid.
Why Your Final Electricity Bill May Differ
This calculator provides an energy-cost estimate based on usage, but your final electricity bill will likely include additional line items. It is critical to understand which components are included and excluded from this estimate.
The calculator estimates usage-based energy costs and does not calculate fixed or standing charges, daily service charges, grid access charges, demand charges, delivery charges, taxes, tariff adjustments, or minimum charges. Because these excluded fees can form a significant portion of a utility bill, the estimated appliance electricity cost shown here reflects only the energy usage component, not the final statement total.
Understanding Your Results
The results provided by the time of use rate calculator display the financial impact of shifting a specific appliance. You will see the estimated appliance electricity cost under TOU rates for that appliance under both a standard flat rate and a time-of-use plan.
The output includes the current flat-rate cost, the TOU cost (assuming usage occurs entirely off-peak), the absolute potential savings, and a flat-rate comparison scaled for daily, monthly, and annual periods. These metrics ensure you have a transparent view of exactly how shifting your usage changes your electricity costs.
Frequently Asked Questions
What is time-of-use electricity?
Time-of-use electricity is a pricing structure where the rate you pay for energy changes depending on the time of day. Instead of a single flat rate, electricity costs more during peak periods when grid demand is high, and less during off-peak periods when demand is low.
How does time-of-use electricity pricing work?
Time-of-use electricity pricing works by dividing the day into distinct rate periods assigned by your utility provider. You are charged a higher premium for electricity consumed during peak hours, incentivising you to shift flexible usage to the cheaper off-peak hours.
How do I calculate appliance cost under time-of-use electricity rates?
You can calculate an appliance's cost under time-of-use rates by determining the kilowatt-hours used, then multiplying that amount by your respective flat, peak, or off-peak rate. Comparing the peak or off-peak cost against the flat-rate cost helps you estimate the financial impact of shifting that appliance's usage.
What are peak and off-peak electricity hours?
Peak electricity hours are the periods when grid demand and energy prices are at their highest, typically occurring in the late afternoon and early evening. Off-peak hours represent times of lowest demand, such as overnight or midday, offering significantly discounted electricity rates.
How do I know whether TOU rates are saving me money?
You know whether TOU rates are saving you money by comparing your total energy cost on a time-of-use tariff against what the exact same consumption would cost on a standard flat rate. If shifting your heavy appliances to off-peak periods offsets your peak usage costs, you are saving money.
Is a time-of-use plan cheaper than a flat electricity rate?
A time-of-use plan is not automatically cheaper than a flat electricity rate. It is only cheaper if you can shift a significant percentage of your household electricity consumption away from the expensive peak hours and into the discounted off-peak hours.
What appliances can I move to off-peak hours?
You can easily move the operation of electric vehicles, pool pumps, electric water heaters, dishwashers, and washing machines to off-peak hours. These high-draw appliances can generally be scheduled to run overnight without disrupting your daily routine or comfort.
Does the calculator include fixed, standing or demand charges?
No, this calculator only estimates usage-based energy costs. It does not calculate fixed charges, standing charges, demand charges, or daily service fees, which will still appear on your final electricity bill regardless of your energy consumption.
Do time-of-use rates and hours vary by provider and season?
Yes, time-of-use rates and peak hours frequently vary depending on your utility provider and the time of year. Many providers enforce different rate schedules during summer and winter months to account for changes in seasonal heating and cooling demand.
How accurate is a time-of-use electricity calculator?
The accuracy of a time-of-use electricity calculator relies entirely on the precision of the rates and appliance usage hours you enter. While it provides an excellent estimate for comparative savings, your final utility bill will include additional unavoidable network and service fees.
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