First-Lien HELOC + Sweep Checking Calculator
Simulate a first-lien HELOC with an integrated sweep checking account. Your net income is deposited directly against the loan balance, suppressing the balance interest is calculated on — starting the day it lands. Expenses draw from the line throughout the month, creating a "sawtooth" daily balance pattern. This calculator runs a true day-by-day simulation and compares the result against a traditional fixed-rate mortgage.
New to the strategy? Read how the All In One Loan™ works.
How the Sweep Mechanism Works
With a first-lien HELOC that has built-in sweep checking, such as the All In One Loan™, your checking account and mortgage are the same account. Every paycheck immediately reduces the balance that daily interest accrues on. As you pay bills during the month, the balance rises back up — but the surplus you don't spend becomes a permanent principal paydown each month. Because interest is calculated on the average daily balance, even money that sits in the account for two weeks before being spent reduces your interest cost.
The Honest Math
The strategy only works with positive monthly cash flow. If your monthly surplus is smaller than the monthly interest on your balance, the balance grows instead of shrinking. First-lien HELOC rates often start above 30-year fixed rates, so compare total interest, not rates. A disciplined borrower making the same extra principal payments on a traditional mortgage often comes out ahead. The calculator shows both trajectories so you can see exactly where the crossover is for your numbers.
What You Can Model
Inputs include starting balance, HELOC rate (default SOFR + 3.25%), deposit frequency (weekly, bi-weekly, semi-monthly, or monthly), total monthly expenses, one-time or annually recurring extra deposits (bonus, tax refund, property sale proceeds), and a traditional fixed-rate comparison. Outputs include payoff time, total interest, interest and time saved, a balance-over-time chart, a daily "sawtooth" detail view, a year-by-year breakdown table, and available credit during the draw period.
All In One Loan™ is a trademark of CMG Financial.
Estimates are for education only. They are not a loan offer or a commitment to lend. Rates are examples, not quotes. Verify any scenario with a licensed loan officer. Jay Miller, Sales Manager and Certified Mortgage Advisor, NMLS #657301. CMG Home Loans Branch NMLS #2475890, 500 Ala Moana Blvd, Suite 5-325, Honolulu, HI 96813. CMG Mortgage, Inc. NMLS #1820. Equal Housing Opportunity.