A walkthrough, end to end.
- 1
Enter the current balance, APR, and your monthly payment.
- 2
Add an optional extra payment to see the accelerated timeline.
- 3
The calculator returns months to payoff, total interest paid, and savings vs. minimum-only payment.
Solve for time given payment
Same payoff formula behind every credit card calculator. If your monthly payment ≤ monthly interest charge, the balance never decreases. Above that threshold, payoff time shrinks rapidly with even small additional payment.
What you can do with this.
Student loan repayment plan
$40K balance at 6% APR. Standard $440/mo = 10 years. Extra $100/mo brings it down to ~7.5 years and saves $4K interest. Use the calculator to find the right balance for your budget.
Credit card payoff
$8K credit card at 22% APR with $200/mo = 78 months and ~$8K interest. Increase to $400/mo = 24 months and ~$1.7K interest. Tripling the time-saved per dollar of extra payment is typical at high rates.
Auto loan early payoff
Auto loan rates 6–8%. Extra payments compress the timeline but interest savings are smaller percentage-wise than credit cards. Often makes sense to allocate to higher-rate debt first.
Mortgage extra principal
30-year mortgage with $100/mo extra principal saves ~5 years and $50–80K interest depending on size and rate. The leverage of mortgage prepayment is large because the loan size is large.
Personal loan acceleration
Personal loans (8–14% APR typical) respond well to extra payments. Confirm your loan has no prepayment penalty (most modern personal loans don't) before accelerating.
When NOT to repay early
If your loan rate is below your investment opportunity (e.g., 3% mortgage vs. 7% expected stock return), invest instead. The math is rate-dependent; high-rate debt should be repaid aggressively, low-rate debt is often better held.
Comparing two repayment plans
Run the calculator with two different monthly payment levels. Compare total interest and timeline. Often choosing $50–100/mo more than the minimum cuts years off and thousands in interest.
Repayment 2026 — what's current
With credit-card APRs at ~23% (Federal Reserve), accelerating high-rate debt has rarely been more financially impactful. Each $100 of extra payment effectively earns 23% guaranteed (the rate you avoid).
Frequently asked.
Most do by default but ALWAYS write 'apply to principal' in the memo. Some lenders apply extras to next month's payment instead — that doesn't accelerate payoff.
Most modern US loans (mortgage, auto, personal) don't have them. Some older mortgages and specialty loans do. Check your loan documents before accelerating.
Rate-dependent. Loan rate above ~6%: pay extra. Loan rate below ~5%: invest. 5–6%: judgment call based on tax treatment, risk tolerance, and certainty preference.
No. Calculations run entirely in your browser.