Retirement
Calculate periodic payment, total interest and total repaid for a fixed-rate 401(k) loan using terms you enter.
Payment per payroll period
$405.53
Total interest
$4,331.67
Total repaid
$24,331.67
Number of payments
60
Result comparison
Plan limits, fees, payroll timing, default treatment and employment-separation rules are not modeled. Check your plan documents.
Calculation method
P is the loan amount, r is the rate per payroll period and n is the number of payments. At a zero rate, payment is amount divided by payment count.
Detailed guide
A 401(k) loan calculator can determine the fixed payment without knowing current legal limits. Enter the amount, rate, term and payroll payment frequency shown by your plan. The formula amortizes the balance to zero over the selected number of payments.
Interest paid on a 401(k) loan generally goes back into the account, but borrowing can still affect investment exposure, cash flow and taxes if the loan defaults. Those consequences depend on plan and tax rules and are deliberately outside this arithmetic estimate.
P is the loan amount, r is the rate per payroll period and n is the number of payments. At a zero rate, payment is amount divided by payment count.
Total interest equals all scheduled payments minus the original amount. Any origination or annual administration fee must be added separately.
Decision guide
Google results emphasize payment terms, plan limits, job-change risk, and the effect on retirement savings. The calculator models the loan parameters you enter; only the plan document can confirm whether a loan is available and how it must be repaid.
Payments return principal and interest to the account under plan rules, but borrowed assets may miss market gains or losses. Contributions can also change while the loan is active. Compare the projected retirement balance with and without borrowing rather than looking only at loan interest.
Leaving an employer can alter the repayment deadline or tax treatment of an unpaid balance. Do not assume the original payroll schedule always continues. Review the plan’s current terms before borrowing and keep a contingency for a job change.
An external loan has its own APR, fees, payment, and credit consequences. A fair comparison uses the same amount and payoff term and includes retirement opportunity cost. The lowest stated rate is not automatically the lowest total cost.
A plan-loan payment reduces the cash available from each paycheck and may compete with new retirement contributions. Model the payment frequency used by the plan, then verify that the remaining budget can support essential expenses, emergency saving, and enough contribution to capture any employer match.
Save a baseline, then change only one input at a time: amount, rate, term, or recurring payment. Record the supporting outputs as well as the headline result—contributions, interest, total cost, remaining balance, or target date. This isolates the assumption that actually changes the decision instead of hiding it inside several simultaneous edits.
Do not tune every assumption until the calculator produces a preferred answer. Start with a cautious case, follow with a central case, and treat the favorable case as an upside scenario. A calculator result is not a lender quote, market forecast, or tax determination; actual dates, rounding, fees, contract rules, and required payments must be checked in primary documents.
Keep enough precision in the inputs and round only the output used for a decision. If the estimate supports a transaction, loan, tax calculation, or long-term plan, repeat it with figures from the contract or official statement. Any difference helps identify the assumption that still needs verification.
Plans can restrict loan size, number of outstanding loans and repayment term. The calculator does not decide whether an input is permitted.
A separation from the employer can change repayment options and tax consequences. Review your plan’s current procedure.
The borrowed amount may no longer receive market returns while outstanding. This page reports loan interest, not foregone investment growth.
The balance is amortized with equal payments at the frequency and annual rate you enter.
Plan mechanics can vary. The payment formula does not assume how each plan records interest or fees.
No. It uses your entered amount and requires you to verify current plan and legal limits.
These primary sources explain the rules and concepts referenced by this calculator. The calculation itself uses only the assumptions entered above.
Updated: August 1, 2026
Useful comparisons
Calculate fixed or declining payments, total interest and a downloadable amortization schedule.
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Estimate net cash from a 401(k) withdrawal using federal, state, local and penalty rates that you supply.