That is the question: this tool helps answer it. Add up what you owe, tell it how you would invest instead, and see both paths on one chart so you can decide where your extra money should go.
Debt payoff vs. investing, over time Live preview
Updates live as you fill in your debts and investing choices below. Show or hide any line with the checkboxes. The payoff lines show how much you still owe; the investing line shows how much you would have saved up. Hover or tap the chart to see exact amounts.
1Your debts
Add every debt you're carrying. Pick a type to see how it's usually treated for tax purposes, or choose Other and just enter a rate.
This is the extra amount, beyond what your debts require, that you're comparing against investing instead. Every debt always gets its own minimum payment: this extra amount is the part you get to choose where to send.
Two ways to order your debts: Snowball pays off your smallest balance first, for quick wins that keep you motivated. Avalanche pays off your highest interest rate first, which usually saves you the most money overall. Either way, once a debt is paid off, its minimum payment rolls onto the next one. The chart above shows both, so you can compare them side by side.
2Investing
What happens if that same extra money goes toward investing instead of debt.
How much your employer adds for every dollar you put in. A 50% match means they add 50 cents for every dollar you contribute. Enter 0% if your plan doesn't offer a match.
The most they will match, as a share of your pay. With a 6% cap, only the money you put in up to 6% of your pay gets matched. Enter 0% if there's no match.
Your pay before taxes, which is what the cap above is measured against. This fills in automatically from the gross monthly income you enter in the Debt-to-income section below. Change it here if your match is based on a different amount.
Why this matters: a lot of employers add free money to your retirement account when you contribute. This is essentially a guaranteed return that's hard for any debt's interest rate to beat, so it's usually worth grabbing before sending extra money at debt. In this tool, your extra monthly payment counts as your contribution, and the matched amount is added to the investing line on the chart.
Over long stretches, a broad mix of U.S. stocks has grown somewhere around 7% to 10% a year on average, but some years are much better and some are much worse.
This uses the same range-of-outcomes modeling as the main investing simulator, without manually adding your own booms or crashes. It plays out 150 different possible markets that average the growth rate above but bounce up and down along the way, about as much as the U.S. stock market has historically. The chart above shows a shaded range covering the middle 80% of those outcomes, with a line through the middle outcome, instead of one single line.
3Debt-to-income ratio
How your required monthly debt payments compare to your income, separate from the extra payment you're choosing to make above. This just measures how much of your income is already tied up in debt.
Your total monthly pay before taxes or anything else comes out.
Under 36% is generally considered healthy, 36–49% draws caution, and 50%+ is a red flag by most lenders. These bands come from general mortgage-lending underwriting guidelines, not a single official rule, and actual thresholds vary by lender and loan type.