401(k) Loan Calculator
Calculate 401(k) loan repayment, interest paid back to yourself, and the opportunity cost of lost market returns. See the true cost of borrowing from retirement.
Mortgage Extra Payments Calculator
Calculate exact savings from extra mortgage payments — monthly, bi-weekly, quarterly, or annually. Compare scenarios and see ROI on prepayment.
$
%
years
$
yr
Base Payment⧉
$2,022.62
Standard monthly P&I
Interest Saved⧉
$105,428.00
188% return on extra payments
Years Saved⧉
6.6 years
79 fewer payments
New Payoff⧉
23.4 yrs
Was 30 yrs
Total Extra Paid⧉
$56,200.00
monthly contributions
Net Savings⧉
$49,228.00
Interest saved minus extra paid
Savings vs Standard
Standard Interest
$408,142.00
With Extra Payments
$302,714.00
Extra Payment Scenarios
| Extra/Period | Payoff | Total Interest | Interest Saved | Total Extra |
|---|---|---|---|---|
| Standard | 30 yrs | $408,142.00 | — | — |
| $100.00 | 26.2 yrs | $346,444.00 | $61,698.00 | $31,400.00 |
| $200.00 | 23.4 yrs | $302,714.00 | $105,428.00 | $56,200.00 |
| $300.00 | 21.2 yrs | $269,696.00 | $138,446.00 | $76,200.00 |
| $500.00 | 18 yrs | $222,590.00 | $185,552.00 | $108,000.00 |
| $750.00 | 15.2 yrs | $183,636.00 | $224,506.00 | $136,500.00 |
| $1,000.00 | 13.2 yrs | $156,743.00 | $251,399.00 | $158,000.00 |
Balance by Year (With Extra Payments)
| Year | Balance | Interest | Extra Paid |
|---|---|---|---|
| 1 | $313,950.00 | $20,622.00 | $2,400.00 |
| 2 | $307,496.00 | $20,217.00 | $2,400.00 |
| 3 | $300,609.00 | $19,784.00 | $2,400.00 |
| 4 | $293,261.00 | $19,323.00 | $2,400.00 |
| 5 | $285,420.00 | $18,831.00 | $2,400.00 |
| 6 | $277,055.00 | $18,306.00 | $2,400.00 |
| 7 | $268,129.00 | $17,746.00 | $2,400.00 |
| 8 | $258,606.00 | $17,148.00 | $2,400.00 |
| 9 | $248,445.00 | $16,510.00 | $2,400.00 |
| 10 | $237,603.00 | $15,830.00 | $2,400.00 |
| 11 | $226,035.00 | $15,104.00 | $2,400.00 |
| 12 | $213,693.00 | $14,329.00 | $2,400.00 |
| 13 | $200,524.00 | $13,502.00 | $2,400.00 |
| 14 | $186,472.00 | $12,620.00 | $2,400.00 |
| 15 | $171,480.00 | $11,679.00 | $2,400.00 |
Planning notes, formulas, and examples
About the Mortgage Extra Payments Calculator
Extra mortgage payments are one of the most powerful financial moves available to homeowners. Every extra dollar goes directly to principal, reducing future interest charges and accelerating payoff. The math is compelling: on a $320K mortgage at 6.5%, contributing an extra $200/month saves over $80,000 in interest and eliminates 7 years of payments.
The impact varies dramatically based on frequency, amount, and when you start. Monthly extra payments provide steady acceleration. Annual lump sums from bonuses or tax refunds deliver a one-time boost. Bi-weekly extra payments add up faster than you might expect. Starting early magnifies the benefit because the outstanding balance — and therefore interest charges — is highest.
This calculator models any combination of extra payment amount and frequency. The scenario comparison table shows seven levels from $0 to $1,000 extra, revealing the diminishing marginal returns at higher amounts. The ROI metric shows your return on extra payments — often 150-300% — making mortgage prepayment one of the safest, highest-return "investments" available.
When This Page Helps
Knowing the size of the benefit is what makes an extra-payment plan usable. This calculator shows the ROI on extra payments, compares seven scenarios side by side, and accounts for payment frequency and start timing so you can choose a plan that fits your cash flow.
How to Use the Inputs
- Enter your current mortgage balance.
- Input the interest rate.
- Set the remaining term in years.
- Enter the extra payment amount.
- Choose the frequency: monthly, bi-weekly, quarterly, or annually.
- Set which year to start extra payments.
- Compare scenarios in the table to find your optimal strategy.
Formula used
Extra payments reduce principal directly. Each period: New Balance = Balance − (Standard Principal + Extra). Interest saved = Standard total interest − Accelerated total interest. ROI = Interest Saved / Total Extra Paid × 100%.Example Calculation
Result: Interest saved: $82,400 — Years saved: 7.1 — Total extra paid: $55,200 — ROI: 149%
Adding $200/month extra to a $320K mortgage at 6.5% for 30 years saves $82,400 in interest and pays off in 22.9 years instead of 30. You contribute $55,200 in extra payments but save $82,400 — a 149% return. The net savings is $27,200.
Tips & Best Practices
- The first $100-200/month extra gives the best ROI — diminishing returns set in above $500.
- Annual lump sums from tax refunds or bonuses are painless — you never miss money you did not have.
- Starting extra payments in year 1 vs year 5 can double the interest savings on long-term loans.
- Automate extra payments — manual strategies fail because life gets in the way.
- Check your servicer accepts principal-only payments — mark extra payments clearly as "apply to principal."
- Compare the net savings (interest saved minus extra paid) to see your true benefit at each level.
Prepayment Strategy
Extra payments work best when they are directed to principal early in the loan, after high-interest debt and emergency savings are covered.
Things To Check
Confirm that your servicer applies the extra amount to principal only, and check whether there are any prepayment limits or posting delays. Compare the interest saved against other uses for the same cash before committing to a recurring amount.
Sources & Methodology
Last updated:
Methodology
This page starts from the standard fixed-rate amortization schedule for the remaining balance, then applies the extra payment directly to principal at the selected frequency. After each extra payment, future interest is recalculated on the lower balance, which is how the model derives the shortened payoff date, total interest saved, and the interest-saved-to-extra-paid comparison.
The worksheet assumes the servicer applies the extra amount to principal without recasting the required payment. Real savings can differ if the lender applies extra funds differently, imposes a prepayment penalty, or delays principal posting.
Sources
- What is a prepayment penalty? (Consumer Financial Protection Bureau) — CFPB explanation that some mortgages can charge a fee when a borrower pays part or all of the loan early.
- Can I be charged a penalty for paying off my mortgage early? (Consumer Financial Protection Bureau) — CFPB overview of how prepayment penalties are disclosed and why borrowers should confirm whether extra-payoff fees apply.
Frequently Asked Questions
Extra payments are applied directly to the principal balance, reducing the amount on which interest accrues. This means each subsequent regular payment has a lower interest component and higher principal component, creating a compounding acceleration effect.
The ROI equals interest saved divided by total extra paid. On a 6.5% mortgage, the ROI is typically 100-300%, meaning you save $1-3 for every dollar of extra payments. This is a risk-free, tax-free return — much better than savings accounts and comparable to stock market returns.
Monthly extra payments are slightly more effective because they reduce the balance sooner, reducing interest over more periods. However, the difference is small. The best strategy is whichever you can actually sustain — a $5K annual lump sum you make is better than $500/month you stop after six months.
Avoid aggressive extra payments if you still carry higher-interest debt, lack an emergency fund, or would give up a strong employer match or higher-confidence return elsewhere. The right answer depends on your mortgage rate, liquidity needs, and risk tolerance.
Contact your loan servicer and specify that additional payments should be applied to principal. Most servicers have an online option for this. Without explicit direction, some servicers may apply extra to the next month's payment (which includes interest) rather than to principal only.
No. Your required monthly payment stays the same regardless of extra payments. Extra payments reduce the principal balance and shorten the loan term, but the minimum required payment is fixed by the original amortization schedule. You can stop extra payments any time without penalty.
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