Find a fixed-fee increase in the bill lines
The fixed service fee rises from USD 8 to USD 14 while usage stays at 200 kWh. Does that USD 6 increase explain the entire bill change?
Open CalculatorInputs and calculation
| Tool input | Value |
|---|---|
| Currency | USD |
| Utility | Electricity (kWh) |
| Previous usage | 200 |
| Current usage | 200 |
| Previous flat rate (USD/unit) | 0.22 |
| Current flat rate (USD/unit) | 0.22 |
| Previous bill (USD) | 52 |
| Current bill (USD) | 58 |
Usage: (200 − 200) × 0.22 = 0. Rate: 200 × (0.22 − 0.22) = 0. Actual bill difference: 58 − 52 = 6. Residual: 6 − (0 + 0) = 6. All effects are in USD.
Tool result · USD 6.00
| Tool input | Value |
|---|---|
| Currency | USD |
| Utility | Electricity (kWh) |
| Previous usage | 200 |
| Current usage | 200 |
| Previous flat rate (USD/unit) | 0.22 |
| Current flat rate (USD/unit) | 0.22 |
| Previous bill (USD) | 52 |
| Current bill (USD) | 52 |
Usage: (200 − 200) × 0.22 = 0. Rate: 200 × (0.22 − 0.22) = 0. Actual bill difference: 52 − 52 = 0. Residual: 0 − (0 + 0) = 0. All effects are in USD.
Tool result · USD 0.00
What the comparison shows
The residual equals the independently observed 6 fee increase. There is no modeled rate or usage effect.
Assumptions and limits
The identification of the fee comes from the line item. A matching residual alone would not prove the source.