How This Estimate Works
Your estimated levelized payment starts from your current average monthly bill, then adds roughly half of any expected rate increase you enter — real utilities typically set a budget billing amount using your trailing 12-month average plus a partial forward adjustment for known or anticipated rate changes, rather than either ignoring the increase entirely or applying the full year's increase on day one. The cash-flow difference rows show how much less you'd pay in your peak month and how much more you'd pay in your lowest month, compared to paying your actual bill each month — this is the entire mechanism of budget billing in one table: it doesn't erase the cost, it just moves it in time.
Why the True-Up Range Is Wide
The true-up estimate spans a wide range on purpose, because the two real-world plan structures produce very different outcomes for the same rate increase. If your utility uses true levelized billing (rolling recalculation, reconciled roughly twice a year — the structure now required for assistance-eligible customers in states like Indiana under 2026's HEA 1002), a rate increase gets absorbed gradually and the low end of the range is more realistic. If you're on older-style traditional budget billing (one flat number for 11 months, one settlement month), the same rate increase can produce a true-up much closer to the high end, since nothing adjusts until that single settlement date. Ask your utility which structure your specific plan uses — the name alone ("budget billing" vs "levelized billing") is a hint but not a guarantee, since some utilities are still finishing the rename.
Before You Enroll
Most utilities require at least 12 months of billing history at your address and a $0 or near-$0 account balance to enroll. See our full is budget billing worth it guide for the true-up risk, enrollment requirements, and who actually benefits from smoothing versus who's better off with standard billing plus their own savings buffer.