What Is the Time-of-Use Rate Calculator?
The Time-of-Use Rate Calculator is a free online tool designed for users who need quick, accurate calculations in the practical calculation space. By entering your current flat rate, tou on-peak rate, tou mid-peak rate, you get instant results including flat rate monthly cost, tou cost, tou cost. No formulas to memorize, no spreadsheets to build — just enter your numbers and get the answer in seconds. Whether you're a beginner or experienced professional, this calculator saves you time and eliminates guesswork.
Why This Calculation Matters
Getting flat rate monthly cost right can make the difference between success and costly mistakes. In practical calculation, small errors compound quickly. Manual calculations are error-prone and time-consuming, especially under pressure. This calculator applies proven formulas used by users worldwide, giving you confidence that your numbers are correct. Use it to get accurate results with precision and avoid common pitfalls that trip up beginners.
When Should You Use This Calculator?
This tool is most useful when you know your current flat rate and need to find the right flat rate monthly cost. It's also great for quick estimates before committing to a decision, and to double-check manual calculations or professional quotes, and when comparing different scenarios side by side. Bookmark this page and come back whenever you need a fast, reliable answer — the calculator is always free and requires no signup.
Time-of-Use Rate Calculator
Compare TOU vs flat rates and find savings by shifting usage to off-peak hours.
Typical TOU Rate Schedules by Region
Average residential rates (¢/kWh) by time period
| Utility/Region | On-Peak | Mid-Peak | Off-Peak | Peak Hours | Best For |
|---|---|---|---|---|---|
| California (SCE) | 38–54¢ | 27–35¢ | 14–18¢ | 4pm–9pm | Solar + battery |
| Arizona (APS) | 24–38¢ | 14–19¢ | 6–8¢ | 3pm–8pm | Pool pump shifting |
| Texas (TXU) | 18–28¢ | 12–16¢ | 8–11¢ | 2pm–7pm | EV charging |
| New York (ConEd) | 30–42¢ | 20–28¢ | 12–16¢ | 2pm–6pm | Appliance shifting |
| Florida (FPL) | 14–22¢ | 11–15¢ | 7–10¢ | 12pm–9pm | EV + pool pump |
| Illinois (ComEd) | 16–24¢ | 10–14¢ | 5–8¢ | 2pm–7pm | Overnight charging |
How to Use This Calculator
- Enter Your Current Flat Rate (¢/kWh): Start by entering your current flat rate — this is the primary input for the calculation.
- Fill In Additional Details: Complete the remaining fields: tou on-peak rate, tou mid-peak rate, tou off-peak rate, monthly usage, % of usage during on-peak hours, % of usage during mid-peak hours, % of peak usage you can shift off-peak. Each value refines the calculation for greater accuracy.
- Click Calculate: Hit the Calculate button to run the numbers. Results appear instantly below.
- Review Your Results: Check your flat rate monthly cost, tou cost, tou cost. Use these figures to inform your next decision or compare against alternative scenarios.
How It Works
Time-of-use (TOU) rate plans charge different electricity prices based on the time of day. This calculator compares TOU vs flat rate costs and shows how much you can save by shifting flexible loads to off-peak hours.
The basic rule:
- On-peak hours are typically 4pm–9pm on weekdays when grid demand is highest
- Off-peak hours are typically 11pm–7am when electricity is cheapest
- Easy loads to shift: EV charging, laundry, dishwasher, pool pump, water heater
- Hard to shift: cooking, lighting, HVAC (though smart thermostats help with pre-cooling)
TOU plans reward flexibility. Households that can shift 40-60% of their peak usage to off-peak hours typically save 15-30% on electricity costs. Those with solar panels, home batteries, or EVs benefit the most from TOU pricing.
Tips & Considerations
- Double-check your current flat rate before calculating — even small input errors can significantly change your results.
- Run the calculator with different values to compare scenarios and find the optimal approach for your situation.
- Pay attention to both flat rate monthly cost and tou cost — they work together to give you the full picture.
- Bookmark this page for quick access next time you need to get accurate results.
- If you're unsure about your % of peak usage you can shift off-peak, start with a conservative estimate and adjust from there.
Frequently Asked Questions
Who benefits most from TOU rate plans?
Households with flexible electricity usage benefit most: those who work from home (can run appliances midday), EV owners (charge overnight), solar panel owners (generate during peak, use stored energy at night), and anyone willing to run laundry, dishwashers, and pool pumps during off-peak hours. If most of your usage is fixed to peak hours (home all evening, heavy AC during peak), TOU may cost more.
What are typical on-peak and off-peak rates?
Rates vary widely by utility. Typical ranges: on-peak 25-50¢/kWh, mid-peak 15-25¢/kWh, off-peak 8-15¢/kWh. Some utilities have super off-peak rates as low as 5¢/kWh for overnight hours. Check your utility's rate schedule for exact numbers — many utilities now offer online TOU comparison tools.
Can TOU plans actually cost me more?
Yes, if your usage is heavily concentrated during peak hours and you cannot shift it. Families home in the evening running AC, cooking, and entertainment will pay more on TOU than flat rate. Always model your actual usage pattern before switching. Many utilities offer a shadow billing period where they show what you would have paid on TOU.
How does a home battery help with TOU rates?
A home battery (like Tesla Powerwall) can charge during off-peak hours at 8-12¢/kWh and discharge during peak hours when rates are 30-50¢/kWh. This arbitrage can save $50-150/month depending on your usage. Combined with solar, it is even more effective — store excess solar generation for peak evening use.
Is the Time-of-Use Rate Calculator free to use?
Yes, completely free with no signup required. Use it as many times as you need — there are no limits or hidden fees.