Debt Payoff Calculator
Find exactly how many months until you are debt-free and the total interest cost at your current payment level.
How to use this debt payoff calculator
- 1Enter your total combined debt balance across all debts you are targeting.
- 2Enter the average APR — use the highest rate if focusing on one debt, or a weighted average if paying all debts simultaneously.
- 3Enter your monthly payment. See what happens when you increase it by $100 or $200.
- 4Use this alongside the avalanche or snowball method to plan your debt payoff sequence.
How it's calculated
n = −ln(1 − iB/P) ÷ ln(1+i). Total interest = (payment × n) − principal balance.
About the Debt Payoff Calculator
Debt payoff planning is one of the highest-return financial activities available. Unlike investing — where returns are probabilistic — the return on debt elimination is guaranteed and equal to your interest rate. Paying off a 14% debt is a guaranteed 14% return.
The emotional weight of carrying debt is often underestimated in purely financial analyses. Research consistently shows that indebted households report higher stress, worse sleep, more relationship conflict, and lower life satisfaction than comparable debt-free households. The psychological return on debt elimination rivals the financial return.
For most people with multiple debts, a written payoff plan outperforms improvised payment decisions. List all debts with balances, rates, and minimum payments. Choose avalanche or snowball. Calculate the payoff date for each debt in sequence. Put extra payment amounts on automatic so they happen without requiring a monthly decision.
Debt payoff and investing are not always mutually exclusive. After capturing any employer 401k match (guaranteed return), the general guidance is to pay off debts with rates above 7–8% before additional investing, since these rates exceed expected market returns. Debts below 5% can often be paid at minimum while investing the difference, since market returns are likely to exceed the debt cost over time. The 5–8% range requires individual judgment based on risk tolerance and emotional relationship with debt.
Frequently asked questions
What is the debt avalanche method and should I use it?
The debt avalanche method pays debts in order of highest interest rate first, while making minimum payments on all others. Mathematically, it minimizes total interest paid. Example: with a $8,000 credit card at 22% and a $5,000 personal loan at 11%, you focus all extra payments on the credit card first. This saves more money than any other payoff sequence. The limitation is psychological — if the highest-rate debt is also the largest balance, it may take months to see progress, which can reduce motivation. If you are disciplined and motivated by math, avalanche is the optimal strategy.
What is the debt snowball method and when is it better?
The debt snowball method pays the smallest balance first regardless of interest rate, then rolls that payment to the next smallest. The 'win' of eliminating a balance provides a psychological reward that research shows helps many people stay committed to their payoff plan. A landmark study by the Harvard Business Review found that snowball users were more likely to completely pay off their debt than avalanche users, even though they paid slightly more in total interest. If you have struggled to maintain debt payoff motivation in the past, snowball may be better despite the higher mathematical cost.
Is debt consolidation a good idea?
Debt consolidation (combining multiple debts into one lower-rate loan) can save significant money and simplify payments — but only if you address the behavior that created the debt. The math is clear: consolidating three credit cards averaging 22% APR into a personal loan at 12% APR saves thousands in interest. The risk: studies show many people run their credit card balances back up after consolidation, leaving them with both the consolidation loan and new card debt. If you consolidate, close or freeze the credit cards to prevent re-accumulation.
How much extra monthly payment actually matters?
Even modest extra payments have outsized impact due to compounding. On a $15,000 balance at 14% APR with a $500/month payment: payoff takes 37 months with $3,225 in interest. Adding just $100/month ($600 total): payoff in 28 months with $2,300 in interest — saving 9 months and $925 in interest from $100/month extra. Adding $300/month ($800 total): payoff in 21 months with $1,550 in interest — saving 16 months and $1,675. The returns to extra debt payments are front-loaded and non-linear: early extra payments save more than later ones because you reduce every future month's interest charge.