Everyday Calculators
Electricity Usage Schedule Calculator
Build an auditable month-by-month schedule for kWh, rate, energy charge, fixed fee, taxes, bill, closing values, and cumulative horizon totals.
Opening variable energy charge-
Opening bill before taxes-
Opening estimated electricity bill-
Electricity use through horizon (kWh)-
Combined monthly change in variable charge (%)-
Variable energy charges through horizon-
Fixed service fees through horizon-
Taxes and surcharges through horizon-
Total scheduled electricity bills through horizon-
Electricity use in final scheduled month (kWh)-
Energy rate in final scheduled month-
Decision view
Indexed electricity-use and rate schedule
Indexed electricity-use and rate scheduleUsage and rate are indexed separately to their opening values so their different units remain readable while the bill path is calculated.
Exact scenario comparisonMonthly change in electricity use (%) changes while all other entered assumptions remain constant.
| Monthly change in electricity use (%) | Opening variable energy charge | Opening bill before taxes | Opening estimated electricity bill | Electricity use through horizon (kWh) | Combined monthly change in variable charge (%) | Variable energy charges through horizon | Fixed service fees through horizon | Taxes and surcharges through horizon | Total scheduled electricity bills through horizon | Electricity use in final scheduled month (kWh) | Energy rate in final scheduled month |
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Electricity schedule
Annual electricity summary and complete monthly schedule
How to use Electricity Usage Schedule Calculator
- Enter an opening month representative of normal conditions.
- Set usage and rate changes independently.
- Review the schedule against seasonal load and known tariff events.
Calculator guide
Understanding Electricity Usage Schedule Calculator
Electricity quantity and unit price can follow different paths. A complete schedule should compound both independently before calculating each month's variable charge and bill.
Detailed calculation process
Compound usage and price on separate monthly paths
The default begins at 780 kWh and $0.18 per kWh, changes usage by -0.5% and price by +0.25% each month, adds a $22 fixed fee and 4% tax, and schedules 24 months.
General formula: E_i = E_0(1+u)^i; r_i = r_0(1+p)^i; V_i = E_i r_i; B_i = (V_i+F)(1+t); E_H = sum E_i; B_H = sum B_i Usage and unit price are compounded independently for each month. Their product creates the variable charge before the constant fixed fee and entered tax are added.
What each symbol means
Worked substitution with the default inputs
The default schedule makes falling kWh and rising price separately visible, so the cumulative bill can be traced to quantity, rate, fixed fee, and tax rather than one blended trend.
Schedule governance
Know which path changes the bill
Separating kWh from price makes the cumulative result explainable.
Worked situations
Practical examples
- Usage can fall 0.5% monthly while the rate rises 0.25%.
- The combined variable-charge change reflects both paths.
- Fixed fees remain constant unless modeled elsewhere.
Better inputs
Useful tips
- Run seasonal schedules rather than forcing one constant trend.
- Check the closing rate against plausible tariff changes.
- Use annual tables to reconcile long horizons.
Before relying on the result
Limitations and common mistakes
- Weather, tariff redesign, billing days, tiers, demand, credits, and equipment turnover are excluded.
- Entered monthly changes compound constantly.
- Fixed fee and tax convention remain unchanged.
Reference
Key terms
- Usage path
- Monthly kWh compounded by its entered change.
- Rate path
- Unit price compounded independently.
- Variable charge
- Scheduled kWh multiplied by scheduled rate.
- Horizon bill
- Sum of energy, fixed fee, and tax across months.
Important note
Historical context: U.S. Energy Information Administration electricity data (https://www.eia.gov/electricity/data.php) and OpenEI Utility Rate Database (https://openei.org/wiki/Utility_Rate_Database). These sources do not predict the user's future tariff or consumption path.
Frequently asked questions
Why can the bill rise while kWh falls?
The rate increase can outweigh the usage reduction.
Does the schedule model seasonal peaks?
No. Use separate assumptions or a seasonal model.
Are fixed fees compounded?
No. The entered fee remains constant.
Is the horizon result discounted?
No. It is a nominal cash schedule.
Why does the final month use months minus one?
The opening inputs are month one, so a 24-month schedule has 23 compounding transitions.
Can a known tariff increase be entered as one monthly percentage?
Only as an approximation; discrete tariff changes should be modeled with separate schedule segments.