Electricity bill change breakdown calculator

Separate usage and rate effects on the variable energy charge. This does not diagnose faults.

Fixed charges and taxes are separate

Usage effect = (current kWh − previous kWh) × previous rate. Rate effect = current kWh × (current rate − previous rate). Together they equal the modelled variable-charge difference. Use monthly records to compare daily usage when period lengths differ.

Two flat rates may not reproduce tiered or time-of-use tariffs. No attribution to cooling, faults or weather is inferred.