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.
Loan Calculator
Calculate loan payments for any amount, rate, and term. Supports monthly, bi-weekly, and weekly frequencies. Includes origination fees, extra payments, and amortization.
$
%
years
%
$
Payment⧉
$512.91
Monthly
Total Interest⧉
$5,775.00
23.1% of principal
Total Paid⧉
$30,775.00
Principal + interest
Origination Fee⧉
$250.00
Net proceeds: $24,750.00
Effective Rate (APR)⧉
4.41%
Including origination fee
Interest Saved⧉
$0.00
No extra payments set
Cost Breakdown
Principal
Interest (23.1%)
Term Comparison
| Term | Payment | Total Interest | Total Paid |
|---|---|---|---|
| 1 yr | $2,180.49 | $1,166.00 | $26,166.00 |
| 2 yrs | $1,136.39 | $2,273.00 | $27,273.00 |
| 3 yrs | $789.19 | $3,411.00 | $28,411.00 |
| 5 yrs | $512.91 | $5,775.00 | $30,775.00 |
| 7 yrs | $395.91 | $8,257.00 | $33,257.00 |
| 10 yrs | $309.96 | $12,196.00 | $37,196.00 |
Amortization Schedule
| Year | Principal | Interest | Balance |
|---|---|---|---|
| 1 | $4,191.00 | $1,964.00 | $20,809.00 |
| 2 | $4,561.00 | $1,594.00 | $16,248.00 |
| 3 | $4,964.00 | $1,191.00 | $11,284.00 |
| 4 | $5,403.00 | $752.00 | $5,881.00 |
| 5 | $5,881.00 | $274.00 | $0.00 |
Planning notes, formulas, and examples
About the Loan Calculator
Whether it is a personal loan, auto loan, or any fixed-rate installment loan, understanding your payment and total cost is the foundation of smart borrowing. A loan calculator turns the abstract — a percentage rate and a term in years — into the concrete: exactly how much you pay every month and how much interest you will pay over the life of the loan.
The standard amortization formula determines equal periodic payments that cover both interest and principal, with early payments weighted toward interest and later payments toward principal. Origination fees and extra payments can significantly change the true cost and payoff timeline.
This general-purpose loan calculator handles any frequency — monthly, bi-weekly, weekly, or quarterly. Enter your loan details to see the periodic payment, an effective APR that factors in origination fees, a term comparison table showing tradeoffs between shorter terms and lower total cost, the impact of extra payments on interest saved and early payoff, and a full amortization schedule.
When This Page Helps
Loan offers vary widely in rates, fees, and terms. This calculator lets you compare options on a level playing field — the effective APR accounts for origination fees, the term comparison shows the payment-versus-cost tradeoff, and extra payment analysis reveals how small additional payments can save thousands.
How to Use the Inputs
- Enter the loan amount you need to borrow.
- Input the annual interest rate.
- Set the loan term in years.
- Choose payment frequency (monthly, bi-weekly, weekly, quarterly).
- Add any origination fee percentage.
- Optionally set an extra payment per period to see early payoff savings.
- Review payments, total interest, and amortization schedule.
Formula used
Payment = P × r(1+r)^n / [(1+r)^n − 1], where P = principal, r = periodic rate (annual rate / frequency), n = total payments (years × frequency).Example Calculation
Result: Monthly payment: $513 — Total interest: $5,767 — Total paid: $30,767
A $25,000 loan at 8.5% for 5 years results in monthly payments of $513. Over 60 payments, you pay $5,767 in interest — 23% of the principal. Adding $50/month extra saves $680 in interest and pays off 5 months early.
Tips & Best Practices
- The shortest term you can afford always minimizes total interest — compare terms in the table.
- Bi-weekly payments (26/year vs 24 semi-monthly) effectively make 13 monthly payments per year.
- Even small extra payments ($25-50) compound significantly over multiple years.
- Origination fees increase the effective rate — a 1% fee on a 3-year loan adds ~0.3% to APR.
- Compare net proceeds (after fees) to ensure you receive the cash you need.
- If choosing between a lower rate with fees vs higher rate without, compare effective APR.
Comparing Loans
Use the calculator to compare the same principal across multiple rates, terms, and fee structures. A small rate change or origination fee can have a larger effect on total cost than the monthly payment alone suggests.
Payment Frequency
Test monthly, bi-weekly, weekly, and quarterly schedules to see how payment cadence changes cash flow and interest paid over time.
Extra Payment Analysis
If you can pay a little more each period, rerun the numbers with that extra amount. Even modest prepayments can shorten the term and reduce total interest meaningfully.
Sources & Methodology
Last updated:
Methodology
This page treats the selected payment interval as the repayment frequency, solves the standard amortization formula for the scheduled payment, and then recomputes the payoff path when origination fees or recurring extra payments are entered. It reports both the contractual payment stream and an effective APR-style comparison that looks at the payment stream relative to the net proceeds after fees.
It is a generic installment-loan worksheet rather than a lender disclosure. Real APR treatment, financed fees, irregular first periods, and product-specific contract terms can change the final numbers shown in the lender's documents.
Sources
- What is an amortized loan? (Consumer Financial Protection Bureau) — CFPB explanation of fixed-payment amortized loans and the principal-versus-interest split over time.
- § 1026.22 Determination of annual percentage rate (Consumer Financial Protection Bureau) — Regulation Z APR rule used as the benchmark for fee-aware annual cost comparisons.
Frequently Asked Questions
The standard amortization formula calculates equal periodic payments covering both principal and interest. The formula is: Payment = P × r(1+r)^n / [(1+r)^n − 1], where P is the loan amount, r is the periodic interest rate, and n is the total number of payments.
The interest rate is the cost of borrowing the principal. The APR (Annual Percentage Rate) includes the interest rate plus other costs like origination fees, discount points, and certain closing costs — giving a more complete picture of the true borrowing cost.
Extra payments reduce the principal balance faster, which means less interest accrues in subsequent periods. This both shortens the loan term and reduces total interest paid. Extra payments early in the loan have the most impact because the balance is highest.
Bi-weekly payments (every 2 weeks, 26 payments/year) equate to 13 monthly payments instead of 12. This extra payment accelerates payoff by about 4-5 years on a 30-year mortgage, saving significant interest. For shorter loans, the benefit is smaller but still meaningful.
An origination fee is a charge by the lender for processing the loan, typically 0.5-5% of the loan amount. It is deducted from proceeds (you receive less) or added to the balance. Always compare the effective APR to see the true cost of loans with different fee structures.
Compare the loan interest rate to expected investment returns (after tax). If the loan charges 8% and you can reliably earn 10% after tax, investing might be better. But the guaranteed "return" of paying down debt often wins for rates above 5-6%, plus the peace of mind of being debt-free sooner.
More in this topic
Amortization Calculator
Calculate loan amortization schedules showing monthly payment breakdown of principal, interest, extra payments, and remaining balance over time.
APR Calculator
Calculate the Annual Percentage Rate (APR) for any loan including fees, points, and closing costs to reveal the true cost of borrowing.