Using the Debt Payoff Simulator

What the Simulator Does

The debt payoff simulator takes your debts, your monthly debt budget, and any extra payments you can make, then projects when you will be debt-free and how much interest you will pay along the way. Every change you make — adding a debt, sliding the extra-payment control, modelling a lump sum — recalculates your payoff date and total interest live.

You can find it at Plan > Debt Planner. The Personal tier is required — Free users see a teaser with an upgrade prompt.

Avalanche vs. Snowball, in Plain English

The simulator can run two well-known strategies side by side.

Avalanche — Save the Most Money

Pay the highest interest rate first while making minimum payments on every other debt. As each debt is cleared, roll its payment into the next-highest-rate debt. Mathematically, this minimises the interest you pay overall.

Choose avalanche if you are motivated by saving money and you do not mind waiting longer for your first "win."

Snowball — Build Momentum Faster

Pay the smallest balance first while making minimum payments on the rest. As each debt disappears, roll its payment into the next-smallest balance. You will pay slightly more interest in total, but you knock out a debt sooner — and that early win is often what keeps people going.

Choose snowball if motivation matters more to you than the last few hundred dollars of interest.

The simulator shows both side by side, so you can see exactly how much interest snowball costs you and how many extra weeks (if any) it adds to your payoff date.

Adding a Lump Sum Scenario

Got a tax refund coming? Selling a car? You can model a one-off payment without committing to it.

Scroll to the lump sum controls below the projection chart
Enter the amount, the month it arrives, and which debt it should be applied to (or leave the target blank to let the simulator apply it according to your chosen strategy)
The payoff date and total interest update instantly so you can see the impact

If you're on the Household tier, scenarios are shared with your household so partners can plan together.

The Sweet-Spot Slider

Not sure how much extra to put toward debt each month? The sweet-spot slider under your debt list lets you drag an extra-payment amount from $0 up to whatever ceiling you set. As you slide:

Your projected debt-free date moves earlier
Total interest paid drops
A small chart highlights the point where additional dollars start giving you smaller and smaller returns — that is your sweet spot

Most people find that the first $100 to $200 of extra payment each month makes the biggest difference; beyond that, the returns flatten. The slider helps you find a number that is meaningful but still realistic given your other goals.

Live-Updating Payoff Dates and Interest

Every input on the page is wired to the same calculation engine, so:

Adding a new debt updates the projection
Changing an interest rate or minimum payment updates the projection
Switching strategies updates the projection
Adjusting the slider or a lump sum updates the projection

There is no "calculate" button to press — what you see is always current.

When a Custom Strategy Makes Sense

Avalanche and snowball are good defaults, but they are not the only options. You might choose a custom order if:

A debt has a promotional rate about to expire (knock it out before the rate jumps)
You have a co-signed loan you want off your record sooner
One debt is causing emotional stress out of proportion to its size — paying it off first might be worth a few extra dollars of interest
You want to clear a credit card to free up a line of credit you may need

Switch to Custom order in the strategy selector and drag your debts into the priority you want. The simulator will respect your order while still rolling cleared payments forward.

Tracking Your Plan

Once you are happy with a plan, save the scenario. As real payments come in from your linked accounts, balances update automatically and the projection adjusts. Pair this with cash flow forecasting to make sure your debt budget fits with the rest of your monthly outflows, and watch your overall progress in net worth tracking.