Compare six monthly water bills
A gardener records six simulated statements from April to September. They want to find when water spending first returned to budget after summer.
Open TrackerInputs and calculation
| Month | Utility | Usage | Bill | Budget | Variance | Month change |
|---|---|---|---|---|---|---|
| 2025-04 | water | 10 m³ | 40 | 48 | -8 | — |
| 2025-05 | water | 12 m³ | 48 | 48 | 0 | 8 (20%) |
| 2025-06 | water | 15 m³ | 60 | 48 | 12 | 12 (25%) |
| 2025-07 | water | 18 m³ | 72 | 48 | 24 | 12 (20%) |
| 2025-08 | water | 16 m³ | 64 | 48 | 16 | -8 (-11.1111%) |
| 2025-09 | water | 12 m³ | 48 | 48 | 0 | -16 (-25%) |
July is 72 − 48 = 24 over budget. September is 48 − 48 = 0. August to September changes by −16, or −16 ÷ 64 = −25%.
What the comparison shows
September is the first month at budget after the June to August overruns. August spending had already fallen but was still 16 above budget.
Assumptions and limits
The month-change column compares adjacent bills. Identifying outdoor use would require submetering or a separate activity estimate.