Early Mortgage Payoff Calculator (USD)
Estimate payoff date, months saved, and interest savings
Early payoff FAQs
Do I need my original loan amount?
No. This calculator works from your current remaining balance, APR, and months left on the schedule.
Does biweekly always beat adding a monthly extra?
If the total extra paid per year is the same, results are similar. Biweekly mainly automates one extra payment a year; a committed monthly extra can match or beat it.
Will my lender lower my required payment?
Not usually. Extra payments reduce principal and time, but your required payment stays the same unless you do a formal recast or refinance.
Can I just make occasional lump sums?
Yes. Applying a lump to principal early in the term can cut a surprising amount of interest. The tool treats your lump as happening now for clarity.
Is this an official payoff quote?
No. It’s an educational estimate. Always request an official payoff statement for exact figures, including per-diem interest and fees.
How to use this early mortgage payoff calculator
1. Start from where you are now
The calculator rebuilds your schedule from your current position, not from your closing documents. Enter the remaining principal, your current APR, and the months left on your existing term. From those three numbers, it reconstructs your scheduled principal-and-interest payment and the interest you are on track to pay if you change nothing. That baseline is the anchor for every payoff comparison.
2. Layer in a monthly extra you can actually keep
A sustainable extra payment beats a heroic one that lasts three months. Use the extra principal field to test an amount that fits your real cash flow. Every dollar above your scheduled payment goes directly to principal. That means the next month’s interest is calculated on a smaller balance, which accelerates the payoff. The summary box translates this into months shaved off and interest avoided so the effect is visible, not abstract.
3. Test the impact of a one-time lump sum
Bonuses, RSU vesting, or savings milestones are powerful when pointed at principal. Plug a lump sum into the calculator as if you applied it now. Because interest accrues on whatever balance is left, a lump sum early in the term usually delivers a larger interest reduction than the same amount applied years later. Combine a lump sum with a monthly extra and you will see a two-step effect: an immediate drop in balance, followed by faster amortization on the lower balance.
4. Compare monthly extra vs biweekly payments
Biweekly payment plans are popular because they quietly add up to roughly one extra monthly payment per year. In this tool, switching to biweekly means half your calculated monthly payment is made every two weeks, using 26 periods per year. The calculator approximates this by applying interest at a per-period rate and stepping through each half-payment until payoff. You can then contrast that timeline and total interest with simply adding a fixed extra to your monthly schedule. Often, a disciplined monthly extra can match or beat a biweekly plan; the summary makes that trade-off explicit.
5. Read the single summary box like a decision sheet
The output keeps everything in one aligned card, similar to an internal loan memo: baseline payoff date, plan payoff date, scheduled payment, total remaining interest on the current path, total interest with your plan, plus the months saved and interest saved. With one glance you can see whether your idea is moving the needle or just adding complexity. Use the copy button to drop a clean scenario summary into your notes, a shared doc, or an email to your advisor.
6. Keep cash safety and other goals in view
An aggressive early payoff plan feels great, but not if it empties your reserves. Before locking in a bigger payment, weigh three things: your emergency fund, your high-interest debts (cards, personal loans), and your retirement saving rate. This calculator is a modeling tool, not a mandate: it can highlight that directing every spare dollar to a 3–4% mortgage while carrying 20% credit card balances or underfunding retirement is usually a poor trade-off. Use the results to balance faster payoff with flexibility and long-term growth.
7. Re-run whenever rates or income change
Your payoff plan is not a one-time decision. If rates fall, you can compare “stay and prepay” vs “refinance with lower rate and smaller or similar payment.” If income rises, you can model a higher extra payment and see how many additional months you can remove. The single summary card lets you snapshot each scenario so you can make adjustments without losing the overall structure.
How the payoff math works (snapshot)
1. Monthly rate: r = APR / 12 / 100. Baseline payment: PMT = L·r·(1+r)n / ((1+r)n − 1), using remaining balance L and months left n.
2. Baseline schedule: each month interest = balance × r; principal = PMT − interest; new balance = balance − principal, until zero.
3. Monthly extra: apply any lump sum now, then use PMT + extra each month. If that amount would not cover interest, we flag it instead of pretending the plan works.
4. Biweekly: approximate with 26 periods/year at rate APR / 26 / 100 and payment ~ PMT / 2 each period (plus proportional extras), capturing the effect of ~1 extra full payment per year.
5. Interest saved = baseline total interest − plan total interest. Months saved = baseline payoff months − plan payoff months (biweekly converted to months). All outputs are estimates only and exclude taxes, insurance, and lender fees.