Overdraft Prevention

The formula multiplies average daily spending by the days between paychecks and adds only your single largest bill, on the theory that the riskiest moment is the day before a paycheck lands, when routine spending has already accumulated and one big bill could hit on top of it. It intentionally isn't a sum of every bill, since bills rarely all land on the same day.

Worst-Case Daily Balance models a rougher scenario by dividing monthly income across the pay-period length and subtracting both your daily spending and the average daily share of all monthly bills — not just the largest one. It's meant to show how tight a typical day within your pay cycle can get if bills are spread out, while Minimum Safe Balance is the specific floor to protect against your single biggest bill hitting near payday.

No — it's a simplified flat estimate: it assumes one $35 overdraft fee avoided per month (a common industry fee amount) any time your calculated minimum safe balance is greater than zero, rather than analyzing how often you've actually overdrafted. Treat it as an illustrative order-of-magnitude figure, not a data-driven prediction specific to your account.

Recommended Buffer adds 25% on top of the minimum specifically as headroom for anything the minimum-safe-balance formula doesn't capture — a bill landing a day early, an unplanned charge, or a daily-spending estimate that runs a little low in practice. Since Minimum Safe Balance is calculated from averages you provide, real weeks can exceed those averages, so the buffer is the more realistic target to actually hold.