Velocity Banking Calculator

Not necessarily. Strategy Effective only compares HELOC Rate against Mortgage Rate directly (line 97) — it reads 0 at this calculator's own defaults because the HELOC rate (8.5%) sits above the mortgage rate (6.5%). But the full month-by-month simulation runs independently of that flag and still reports 283 Months Saved and roughly $260,490 Interest Saved at those same defaults, because chunking the HELOC onto the mortgage and clearing it quickly can help even when its stand-alone rate is higher.

No. Monthly Income dominates Months Saved, moving it by roughly 13% under a 10% nudge — ahead of Monthly Expenses and Mortgage Balance. But Interest Saved responds most to Mortgage Rate instead, at roughly 26%, more than double Monthly Income's roughly 11% effect on that particular output, because the rate directly sets how much interest accrues on whatever mortgage balance remains at any point in the simulation.

Exactly at your entered Mortgage Rate. Strategy Effective is 1 whenever HELOC Rate is strictly below Mortgage Rate and 0 otherwise (line 97), so at this calculator's default 6.5% mortgage rate, any HELOC Rate below 6.5% flips the flag to 1, and 6.5% or above keeps it at 0 — the flag itself does not measure how much the strategy actually saves, only whether the HELOC happens to be cheaper than the mortgage.

No — Standard Payoff Time stays fixed at 360 months no matter what you enter for Mortgage Balance, Mortgage Rate, or any other input. The standard monthly payment is computed with the classic amortization formula (lines 73-78) specifically solved to clear whatever balance and rate you enter in exactly 360 months, so the payoff length is baked into how that payment is derived rather than something the simulation discovers.

Monthly Income, by a wide margin: a 10% nudge moves Velocity Payoff Time by roughly 48%, well ahead of Monthly Expenses at roughly 32%. Both feed the same monthly surplus that gets funneled into paying down the HELOC between chunk draws (lines 130-133), but income's larger effect here reflects the specific dollar amounts at this calculator's defaults, not a fixed rule that income always outweighs expenses.