How to use this calculator
Start with your current monthly kWh and rate. Choose a percentage reduction in total energy and enter a scenario rate. Fixed charges and tax stay the same in both bills, so you can isolate usage and rate changes.
The formula
Scenario kWh = current kWh × (1 − reduction% ÷ 100). Saving = current bill − scenario bill.
Worked example
Reducing 300 kWh by 15% gives 255 kWh. With a rate of 0.16, fixed charge of 8.00 and 7% tax, the current bill is 59.92 and the scenario is 52.22. The modeled monthly saving is 7.70.
Assumptions and limitations
The reduction is a planning assumption, not a promise about a behavior or product. A higher future rate may outweigh lower usage. Negative savings mean the scenario costs more. Annual savings repeat the same monthly difference 12 times.
Frequently asked questions
Does a 15% energy reduction mean a 15% lower bill?
Usually not when there is a fixed charge. The energy component falls, while the fixed charge remains unchanged.
Can I compare a price increase?
Yes. Enter a higher scenario rate. Set the usage reduction to zero to isolate the effect of the rate change alone.
Estimates only. Use your utility tariff and appliance energy label for more accurate inputs.