First-Lien HELOC Payoff Strategy Calculator

A first-lien HELOC (also called velocity banking) replaces your traditional fixed mortgage with a home equity line of credit in the first lien position. Your paycheck is deposited directly against the HELOC balance, reducing the average daily balance that interest is calculated on. Done with discipline, the strategy can cut payoff time by 5-10 years compared to a traditional mortgage — but it requires variable-rate tolerance and consistent positive cashflow.

How First-Lien HELOC Velocity Banking Works

Step 1: Refinance your traditional mortgage into a first-lien HELOC at 70-80% LTV. Step 2: Each payday, deposit your full paycheck against the HELOC balance, dropping the balance dramatically. Step 3: As bills are paid throughout the month, the balance climbs back up. Step 4: Interest is calculated daily on the average balance — which is much lower than your starting balance because your paycheck parks there for 1-2 weeks. Step 5: Apply free cashflow (income minus expenses) as additional paydown. The result: same total payments but interest charged on a much smaller average balance.

Risks and Discipline Required

First-lien HELOCs are variable-rate, typically tied to Prime + 1%. If Prime jumps 3%, your rate jumps 3%. The strategy requires (a) consistent positive monthly cashflow — if you ever go negative, you're adding to the balance; (b) iron discipline — money sitting in the HELOC is psychologically available to spend; (c) tolerance for rate volatility. Best fit: high-income earners with stable jobs and aggressive savings habits. Worst fit: variable income, tight budget, or anyone tempted to use the available credit for discretionary spending. Compare to simply making extra principal payments on your fixed mortgage — often achieves 80% of the benefit with none of the risk.

Last updated May 2026. Sources: CFPB Owning a Home.