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Time-of-Use Electricity Cost Calculator

Estimate energy charges when your utility uses different peak and off-peak prices. Enter the daily energy in each period, the rates, billing days, and any fixed charge.

Calculate a time-of-use estimate

Use the same currency for both rates and the fixed charge. Check your utility tariff for exact time windows.

Average daily energy during the peak-price period.
Average daily energy during the lower-price period.
Use the peak unit price from your tariff.
Use the off-peak unit price from your tariff.
Enter 1–366 days.
Optional fixed charge; do not add it twice.
Formula
Peak charge = peak kWh/day × days × peak rate. Off-peak charge = off-peak kWh/day × days × off-peak rate. Total = both energy charges + fixed charge.

Use your actual tariff

Time-of-use schedules are set by local utilities and may vary by season, weekday, weekend, or customer type. This calculator does not assume a universal peak schedule. Read your tariff and use its specific time windows and rates.

Prepare the inputs

  1. Check the exact peak and off-peak periods on your bill or tariff document.
  2. Estimate or measure energy in each period separately. Interval data from a smart meter is often more useful than adding appliance nameplate watts.
  3. Use a representative daily average and the correct number of billing days.
  4. Enter any fixed service charge once; keep taxes and other adjustments separate.

Worked example

At 3 kWh/day during peak at 0.30 and 5 kWh/day off-peak at 0.12, a 30-day period costs 27 + 18 = 45 currency units for energy, before fixed fees or taxes.

Important limits

This estimate assumes the daily split and rates remain constant. It does not model demand charges, tiered blocks, seasonal rates, taxes, power factor, export credits, or minimum bills. Review the complete tariff before making a decision.

Related tools

Use the Electricity Cost Calculator, Home Energy Planner, or read how to understand an electricity bill.