A 401(k) loan is paid back through automatic after-tax payroll deductions that your employer routes directly into your retirement account, typically over a maximum of five years. Every payment covers both principal and interest, and because you’re borrowing from yourself, the interest lands in your account rather than at a bank. The system runs on its own once it starts, but two events can break it: missing payments long enough to trigger a deemed distribution, and leaving your job before the balance is repaid.
How the Payroll Deduction Works
Once your plan administrator approves the loan, your employer’s payroll department sets up recurring deductions from each paycheck. Those deductions come out on an after-tax basis, meaning the money is withheld after federal and state income taxes have already been taken. Payroll then forwards each deduction to the plan provider, which credits your individual account.
You don’t write checks or log into a portal. The process runs automatically until the loan is paid off or something disrupts it, such as a job change or an unpaid leave. That automation is one reason 401(k) loans default less often than most consumer debt, since the money is taken before you see it. The trade-off is that your take-home pay shrinks for the life of the loan, and many borrowers underestimate how noticeable that reduction feels over several years.
The Five-Year Clock and Payment Schedule
Federal law caps general-purpose 401(k) loans at a five-year repayment window from the date the funds are disbursed. Payments must be “substantially level,” meaning each installment covers both principal and interest in roughly equal amounts, and they have to occur at least once per calendar quarter.1Internal Revenue Service. Retirement Plans FAQs Regarding Loans Most plans deduct on every pay period rather than quarterly, which keeps the balance dropping smoothly.
There is one major exception. A loan used to buy your primary residence can extend beyond five years, with the exact maximum term set by your plan rather than by a specific federal cap.1Internal Revenue Service. Retirement Plans FAQs Regarding Loans Not every plan offers the extended term, so check your summary plan description before assuming you qualify.
What Each Payment Actually Costs You
Most plans set the loan interest rate at the prime rate plus one percentage point, and the rate is usually locked in when the loan is issued so it won’t move with later rate changes. Each payment splits between interest and principal, just like a conventional amortizing loan. The difference is that both parts land back in your own account.
That sounds like a free lunch. It isn’t.
The money you repay goes in with after-tax dollars. When you eventually withdraw those funds in retirement, they get taxed again as ordinary income. The principal portion was already pre-tax money in the account, so this creates a layer of double taxation on the repaid amounts that wouldn’t exist if you had left the money invested. The interest portion is hit especially hard because it never had pre-tax status to begin with: you earn it with after-tax income, deposit it into the plan, and then pay taxes on it a second time at withdrawal.
There’s also an opportunity cost. While the borrowed funds sit outside your account, they aren’t participating in market growth. You’re paying yourself back at a fixed rate, but if your investments would have returned more than that over the same period, you end up behind. Over a long horizon, lost compounding can outweigh the interest you paid yourself.
What Happens If You Miss a Payment
Missing a payment doesn’t instantly trigger a default. Many plans include a cure period that gives you time to catch up. The maximum allowable cure period runs through the last day of the calendar quarter after the quarter in which the payment was due.2Internal Revenue Service. Issue Snapshot – Plan Loan Cure Period Miss a payment due in February, and you have until June 30 to make it up. Miss one due in November, and the deadline extends to March 31 of the following year.
If the cure period passes without payment, the entire outstanding balance, including accrued interest, is treated as a deemed distribution.2Internal Revenue Service. Issue Snapshot – Plan Loan Cure Period The IRS treats it as though you took a withdrawal. The full amount becomes taxable income for that year, and your plan administrator reports it on Form 1099-R.3Internal Revenue Service. 401(k) Plan Fix-It Guide – Participant Loans Don’t Conform to the Requirements of the Plan Document and IRC Section 72(p) If you’re under 59½, you’ll also owe a 10% early distribution penalty on top of the regular income tax.4Internal Revenue Service. Retirement Topics – Exceptions to Tax on Early Distributions
Once a deemed distribution has occurred, there’s no way to put the money back. The tax bill arrives the following April.
Paying the Loan Off Early
Most plans let you pay off a 401(k) loan ahead of schedule without any prepayment penalty. Start by requesting a payoff quote from your plan administrator, which gives you the exact remaining balance including accrued interest through a specific date. Extra payments are typically made outside the payroll system using a personal check or ACH transfer from your bank account. These manual submissions need specific documentation so the plan provider codes them as loan repayments rather than new contributions.
Paying off early frees up more of your paycheck and gets your full balance back to work in the market sooner. One caution if you’re thinking about borrowing again right after: a 12-month lookback rule reduces the $50,000 cap by the difference between your highest outstanding loan balance during the past 12 months and your current balance, so paying off a large loan doesn’t immediately restore access to the full amount.1Internal Revenue Service. Retirement Plans FAQs Regarding Loans
Repayment During a Leave of Absence
When you take an unpaid leave and there’s no paycheck to deduct from, your plan may allow loan payments to be suspended for up to one year. Once you return, you have to make up the missed payments, either by increasing each remaining installment or making a lump-sum catch-up payment. The overall five-year deadline doesn’t shift because payments were paused.1Internal Revenue Service. Retirement Plans FAQs Regarding Loans
Military Service Members
Service members on active duty get broader protections from two separate laws. Under the plan loan rules in the tax code, a plan can suspend loan payments for the entire duration of military service, not just one year. When the service member returns, the five-year repayment deadline is extended by the length of the military service period.3Internal Revenue Service. 401(k) Plan Fix-It Guide – Participant Loans Don’t Conform to the Requirements of the Plan Document and IRC Section 72(p) A two-year deployment effectively gives you seven years total to repay.
Separately, the Servicemembers Civil Relief Act caps interest at 6% per year on debts incurred before entering military service, and any excess interest is forgiven entirely.5Office of the Law Revision Counsel. 50 U.S. Code 3937 – Maximum Rate of Interest on Debts Incurred Before Military Service If your 401(k) loan was taken out before you were called to active duty, this cap can reduce your effective rate during the service period.
Repayment After You Leave Your Job
This is the scenario that catches the most borrowers off guard. When you leave your employer, whether voluntarily or through a layoff, payroll deductions stop and the remaining loan balance typically comes due. If you can’t pay it back, the plan administrator performs a loan offset, reducing your account balance by the unpaid amount.6Internal Revenue Service. Plan Loan Offsets That offset is treated as a distribution: taxable income, and potentially subject to the 10% early withdrawal penalty if you’re under 59½.
You do have a window to avoid the tax hit. A loan offset that qualifies as a “qualified plan loan offset amount,” which includes offsets triggered by job separation, can be rolled over into an IRA or another eligible retirement plan. The deadline to complete that rollover is your federal tax filing due date for the year the offset occurs, including extensions. Filing for an extension can push the deadline to October 15 of the following year, giving you more time to come up with the funds.6Internal Revenue Service. Plan Loan Offsets
Some plans also allow you to continue making manual payments directly to the plan provider after separation, at least for a limited period. This option varies entirely by plan, so ask your administrator right away if you’re leaving with an outstanding balance. The worst outcome is doing nothing and letting the offset become a taxable distribution by default.