Refinance a 401(k) Loan? Costs and Key Rules

You generally cannot refinance an existing 401(k) loan into a new 401(k) loan, though a plan may allow you to repay the old balance with a new loan if its rules permit. This calculator estimates the monthly payment and total interest for a hypothetical replacement loan; enter its amount, APR, and term to see the figures. It does not determine whether your workplace plan allows the transaction or account for the old loan’s payoff conditions.

Formula

The calculator uses the standard fixed-payment loan formula. Monthly payment = principal × monthly rate ÷ [1 − (1 + monthly rate)^{−number of payments}]. The monthly rate is APR ÷ 1,200, and the number of payments is the term in years × 12. Total interest is the rounded monthly payment × number of payments − principal.

• Principal (p): the hypothetical amount borrowed, in dollars.
• APR (apr): annual percentage rate entered as a percentage, such as 8 for 8%.
• Term (yrs): repayment period in years.
• Monthly payment (pmt): the fixed payment in dollars, rounded to cents.
• Total interest (int): estimated interest over all scheduled payments, in dollars.

Worked Example

Using the calculator’s defaults—$20,000 principal, 8% APR, and five years—the monthly rate is 0.08 ÷ 12 = 0.0066667, and there are 5 × 12 = 60 monthly payments.

Monthly payment = 20,000 × 0.0066667 ÷ [1 − (1.0066667)⁻⁶⁰] = $405.53 after rounding to cents.

Total interest = $405.53 × 60 − $20,000 = $4,331.80. This is a hypothetical amortizing loan calculation, not a quoted 401(k) plan-loan offer or a prediction of the cost of replacing an existing balance.

Assumptions

• The interest rate stays fixed throughout repayment.
• Payments are equal, made monthly, and begin one month after borrowing.
• Interest compounds monthly at APR ÷ 12.
• The estimate excludes fees, taxes, insurance, and other charges; none are represented as inputs.

Can You Refinance a 401(k) Loan?

“Refinance” can mean different things here. A conventional refinance replaces one debt with a new loan. A 401(k) loan is borrowed from an employer-sponsored retirement plan, and the plan’s written terms control whether borrowing is available, how many loans may be outstanding, and whether a new loan can be used to pay off an existing one. There is no general rule that every plan offers this option.

In some plans, a participant may be able to take another plan loan and use the proceeds to repay the first. That is not automatic refinancing: the plan must permit the new borrowing, the participant must meet its conditions, and the amount available may not equal the old loan’s payoff balance. Ask the plan administrator for the summary of loan procedures and a payoff figure before treating this as an option.

What Happens to the Existing Loan?

Before making a decision, clarify how the current loan is repaid and what happens if employment ends or scheduled payments stop. Plans can have specific repayment and default procedures. A missed payment may have consequences under the plan and applicable rules; do not assume it can simply be rolled into a new loan or paid later without effects. For account-specific details, consult the plan administrator or recordkeeper.

Also distinguish the loan balance from the amount needed to pay it off on a particular date. The payoff may reflect accrued interest or payment timing. A replacement loan, if allowed, may have a different payment schedule and duration. The calculator’s principal should represent the amount actually borrowed for the hypothetical new loan, not necessarily the original amount of the old loan.

Costs and Important Trade-Offs

A plan loan’s interest is generally credited to the participant’s account under the plan’s terms, but that does not make borrowing cost-free. The borrowed money is not invested in the account while outstanding, so its investment results differ from what they might have been otherwise. Loan charges may also apply, and a longer repayment period can change both the monthly payment and total interest. The calculator models only scheduled payments and interest at a fixed APR.

For example, a hypothetical $20,000 balance replaced over five years has a different payment from the same amount repaid over three years, even at the same APR. A shorter term usually means larger scheduled payments but fewer payments; a longer one usually spreads repayment out. This arithmetic does not establish which term is suitable for someone’s circumstances.

Alternatives and Questions to Check

Rather than assuming a new plan loan is possible, identify the exact problem you are trying to solve—payment size, payoff timing, or another expense—and gather the relevant figures. Depending on circumstances, people may compare repayment under the existing plan, other borrowing options, or changes to a budget. Those options have different costs and conditions and are not modeled here.

• Does the plan permit a second loan while the current one is outstanding?
• Can new loan proceeds be applied to the old loan, and what documentation is required?
• What are the current payoff amount, repayment schedule, fees, and consequences of missed payments?
• How would a job change affect repayment, according to the plan’s written procedures?
• Does the new loan’s payment fit the cash flow you have calculated, without assuming approval?

Frequently Asked Questions

Can I use a new 401(k) loan to pay off an old one?
Possibly, but only if the plan’s rules allow another loan and permit that use. Confirm the procedures and payoff amount with the plan administrator.

Is refinancing a 401(k) loan the same as consolidating debt?
No. A plan loan is borrowed from retirement-plan assets, while debt consolidation usually combines debts through a separate borrowing arrangement. The calculator shows generic fixed-payment arithmetic, not plan-specific terms.

Does a 401(k) loan refinance lower the payment?
It depends on the new principal, APR, and term. A longer term can reduce a scheduled payment while increasing total interest under the formula, but plan rules and any charges may change the actual figures.

What happens if I leave my job with a 401(k) loan?
There is no single answer for every plan. Repayment and default procedures can depend on plan terms and applicable rules, so request the written explanation from the administrator before relying on an assumption.

Does the calculator tell me whether I qualify?
No. It calculates a payment and total interest from the numbers entered. It does not check eligibility, plan loan limits, outstanding balances, fees, or approval.

Can I enter my current 401(k) loan balance as the amount?
You can use it for a rough illustration, but a payoff quote may differ from the displayed balance. Use the amount that would actually be borrowed, and verify the payoff and new-loan terms with the plan.

This calculator is for educational estimates only, and the lender’s disclosure gives the exact figures.

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in p | Loan amount | $ | 20000 | 1 | 100000000
in apr | Interest rate (APR) | % | 8 | 0.01 | 100
in yrs | Loan term | years | 5 | 0.0833 | 50
out pmt | Monthly payment | $ | p * (apr / 1200) / (1 - (1 + apr / 1200) ^ -(yrs * 12)) | 2
out int | Total interest | $ | pmt * yrs * 12 - p | 2