401k Loan Calculator — Calculate Loan Payments, Interest & Impact (2025)

Free 401k loan calculator for 2025. Calculate monthly payments, total interest, and impact on retirement savings. Understand IRS rules, limits, and repayment terms.

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401k Loan Calculator — Calculate Loan Payments, Interest & Impact (2025)

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Common Loan Scenarios

$

Your vested balance determines maximum loan amount

$

Max allowed: $0 (50% of balance or $50,000)

%

Typically Prime Rate + 1-2%

IRS maximum is 5 years (60 months)

Important 401(k) Loan Rules

  • • Maximum loan: 50% of vested balance or $50,000 (whichever is less)
  • • Repayment term: Maximum 5 years (longer for home purchases)
  • • Repayment method: Payroll deductions with after-tax dollars
  • • Interest paid: Goes back into your 401(k) account
  • • Default risk: If you leave your job, loan must be repaid or becomes taxable distribution
  • • Double taxation: Interest is repaid with after-tax dollars, then taxed again in retirement

How to Use the 401k Loan Calculator

1

Check Your Vested Balance

Find your current vested 401(k) balance on your most recent statement or online account. This determines your maximum loan amount.

2

Enter Loan Amount

Input how much you need to borrow. Remember: maximum is 50% of vested balance or $50,000, whichever is less.

3

Set Interest Rate

Enter the interest rate (typically Prime Rate + 1-2%). Most 401(k) plans set this rate based on current market conditions.

4

Choose Repayment Term

Select your loan term in months (maximum 5 years for general loans, longer for home purchases). Payments are made through payroll deductions.

5

Review Amortization Schedule

Analyze the interactive chart showing your payment breakdown, remaining balance, and total interest paid over the loan term.

6

Export & Compare Scenarios

Download your loan data and try different scenarios to find the optimal loan structure for your situation.

Key Features

Accurate IRS-compliant calculations

Interactive amortization schedule

Visual impact analysis

Export loan data

Real-time scenario comparison

Complete Guide: Understanding 401(k) Loans and Their True Cost

Written by Jurica ŠinkoNovember 12, 2025
Visual representation of 401k loan calculations showing monthly payments, interest costs, and long-term retirement impact

Key Takeaway

A 401(k) loan allows you to borrow up to $50,000 or 50% of your vested balance, but it comes with significant risks. While the interest you pay goes back into your account, you're losing potential investment growth, facing double taxation on interest, and risking a costly default if you leave your job. Before borrowing, exhaust all other options and ensure you can repay within 1-2 years.

What Is a 401(k) Loan and How Does It Work?

A 401(k) loan allows you to borrow money from your own retirement savings and pay it back with interest over time. Unlike a 401(k) withdrawal, which permanently removes money from your account and triggers taxes and penalties, a loan must be repaid. The interest you pay goes back into your 401(k), which sounds appealing—but there's a significant catch.

According to IRS rules, you can borrow up to 50% of your vested account balance or $50,000, whichever is less. If your vested balance is $30,000, you can borrow up to $15,000. If your balance is $200,000, you're capped at $50,000. The loan must be repaid within five years (unless used to purchase your primary residence), and payments must be made at least quarterly through payroll deductions.

The Hidden Costs: Why 401(k) Loans Are More Expensive Than They Appear

Many financial advisors call 401(k) loans "the most expensive way to borrow money" because of hidden costs most borrowers don't consider. Let's break down the true cost:

1. Lost Investment Growth (Opportunity Cost)

When you borrow $30,000 from your 401(k), that money stops working for you. If the market returns 7% annually (the historical average), you're missing $2,100 in growth in year one, $2,247 in year two, and so on. Over a 5-year loan, you could lose $12,000-$15,000 in potential growth. If you're younger, the compounding effect is even more dramatic—a 30-year-old could lose over $100,000 in retirement value.

2. Double Taxation on Interest

Here's the trap: You repay the loan with after-tax dollars, but you'll be taxed again when you withdraw that money in retirement. If you're in a 22% tax bracket, you're effectively paying 44% tax on the interest portion of your payments. A $5,000 interest payment actually costs you $6,100 in pre-tax earnings.

3. Reduced Contributions

Many borrowers can't afford to maintain their regular 401(k) contributions while repaying a loan. If you normally contribute $500/month and reduce it to $200/month during a 5-year loan, you've lost $18,000 in contributions—plus decades of compound growth on that money.

4. The Job Loss Risk

If you leave your job (voluntarily or not), the remaining loan balance typically becomes due within 60-90 days. If you can't repay it, the outstanding amount becomes a taxable distribution. On a $20,000 balance, you'd owe $4,400 in taxes (22% bracket) plus a $2,000 early withdrawal penalty if you're under 59½. That's $6,400 in immediate costs.

IRS Rules and Regulations: What You Must Know

The IRS has strict rules governing 401(k) loans, and violating them can trigger severe tax consequences. Understanding these rules is crucial before borrowing.

Borrowing Limits

  • • Maximum: 50% of vested balance or $50,000 (whichever is less)
  • • Minimum: Typically $1,000 (varies by plan)
  • • Multiple loans: Total outstanding cannot exceed limits
  • • Calculation: Based on highest balance in past 12 months

Repayment Requirements

  • • Term: Maximum 5 years (60 months)
  • • Frequency: At least quarterly payments
  • • Amount: Substantially equal installments
  • • Method: Payroll deduction (after-tax dollars)
  • • Residential: Up to 30 years for home purchases

Common Reasons People Take 401(k) Loans (And Better Alternatives)

According to a 2022 survey by the Plan Sponsor Council of America, the average 401(k) loan was $15,000, up from $10,000-$11,000 in previous years. Understanding why people borrow can help you evaluate if it's the right choice for you.

1. Emergency Medical Expenses

Why it's tempting: Medical bills can be overwhelming, and a 401(k) loan offers quick access to cash without a credit check.

Better alternatives: Negotiate payment plans with providers (often 0% interest), use HSA funds if available, apply for hospital financial assistance programs, or consider a 0% APR credit card for short-term needs.

Bottom line: Medical debt has low or no interest options. A 401(k) loan's hidden costs make it one of the most expensive ways to pay medical bills.

2. Home Down Payment

Why it's tempting: Getting into a home sooner and avoiding PMI (Private Mortgage Insurance) with a larger down payment.

Better alternatives: FHA loans require only 3.5% down, conventional loans offer 5% down options, down payment assistance programs exist in most states, or wait and save aggressively for 12-18 months.

Bottom line: Using retirement funds for a home purchase is risky. If you lose your job, you could lose both your home and retirement security.

3. Debt Consolidation

Why it's tempting: High-interest credit card debt (18-25% APR) seems more expensive than a 401(k) loan (6-8% interest).

Better alternatives: Balance transfer cards with 0% APR for 12-21 months, personal loans from credit unions (7-18% APR), debt management plans through nonprofit credit counseling (often 6-8% effective rate), or the debt snowball/avalanche methods.

Bottom line: While the math might favor a 401(k) loan, the risks (job loss, double taxation, lost growth) make credit card debt or personal loans often safer choices.

4. Education Expenses

Why it's tempting: Investing in education or paying for children's college seems like a worthy cause.

Better alternatives: Federal student loans offer low rates (4.99% for undergrad, 6.54% for grad), income-driven repayment plans, potential loan forgiveness, and deferment options. 529 plans offer tax-free growth for education.

Bottom line: Education is important, but not at the cost of your retirement security. Student loans have flexible repayment options; 401(k) loans don't.

The 401(k) Loan Formula: How Payments Are Calculated

Our calculator uses the standard amortization formula to calculate your monthly payments. Understanding this helps you see how much each payment goes toward principal versus interest.

Monthly Payment Formula

M = P × [r(1+r)^n] / [(1+r)^n - 1]

Where:

  • M = Monthly payment
  • P = Principal loan amount
  • r = Monthly interest rate (annual rate ÷ 12)
  • n = Total number of payments (loan term in months)

Example: For a $25,000 loan at 6.5% annual interest for 60 months:
• r = 0.065 ÷ 12 = 0.005417
• M = 25,000 × [0.005417(1+0.005417)^60] ÷ [(1+0.005417)^60 - 1] = $488.68

Strategic Considerations: When a 401(k) Loan Might Make Sense

Despite the drawbacks, there are rare situations where a 401(k) loan might be your best option. Here are the criteria that should ALL be met:

When a 401(k) Loan Could Be Justified

  • ✓ You have extremely stable employment (government, tenured position, or essential role)
  • ✓ You can repay within 12-24 months, not the full 5 years
  • ✓ You've exhausted all other options (emergency fund, 0% credit cards, personal loans)
  • ✓ The loan prevents catastrophic financial consequences (foreclosure, bankruptcy)
  • ✓ You can maintain full 401(k) contributions while repaying the loan
  • ✓ You have no other retirement savings to fall back on if you lose your job

Action Steps: What to Do Before Taking a 401(k) Loan

Step 1: Explore Every Alternative

List every other funding source: emergency fund, HSA, FSA, 0% credit cards, personal loans, family help, payment plans, or selling assets.

Step 2: Calculate the True Cost

Use our calculator to see monthly payments, but also estimate lost investment growth (use 7% as conservative estimate) and double taxation cost.

Step 3: Assess Job Security

Honestly evaluate your job stability. If there's any risk of layoffs, restructuring, or you might want to change jobs, don't take the loan.

Step 4: Plan for the Worst

What happens if you lose your job? Do you have savings to cover the loan balance? Could you handle the tax bill and penalty?

Step 5: Commit to Continued Contributions

Promise yourself to maintain full 401(k) contributions. Reducing contributions while repaying a loan compounds the damage to your retirement.

Key Takeaways

A 401(k) loan might seem like an easy solution to short-term cash needs, but the hidden costs—lost investment growth, double taxation, and job loss risk—make it one of the most expensive borrowing options available. Before taking a loan, exhaust every alternative and ensure you can repay it within 12-24 months while maintaining your regular contributions.

Remember: Your 401(k) is for retirement, not a piggy bank. Every dollar borrowed today could cost you $5-$10 in lost retirement value. Use this calculator to understand the true cost, but think of it as a tool to discourage borrowing rather than encourage it.

About the Author

Jurica Šinko

Finance Expert, CPA, MBA with 15+ years in corporate finance and investment management

Connect with Jurica

Frequently Asked Questions

How much can I borrow from my 401(k)?

The IRS limits 401(k) loans to 50% of your vested account balance or $50,000, whichever is less. If your vested balance is $80,000, you can borrow up to $40,000. If your balance is $120,000, you're limited to $50,000. Some plans also have minimum loan amounts, typically $1,000.

What happens if I leave my job with an outstanding 401(k) loan?

If you leave your employer with an outstanding 401(k) loan, the remaining balance typically becomes due within 60-90 days. If you can't repay it, the outstanding amount is treated as a taxable distribution. You'll owe income tax on the balance plus a 10% early withdrawal penalty if you're under age 59½. Some plans allow you to continue payments after leaving, but this is rare.

Is the interest I pay on a 401(k) loan tax-deductible?

No, interest paid on a 401(k) loan is not tax-deductible. Additionally, you're repaying the loan with after-tax dollars, and then you'll be taxed again when you withdraw the money in retirement. This creates double taxation on the interest portion of your loan payments.

How does a 401(k) loan affect my retirement savings?

A 401(k) loan can significantly impact your retirement savings in three ways: 1) The borrowed money isn't invested, missing potential market gains. 2) Many participants reduce or stop contributions while repaying loans. 3) Interest paid back is often less than historical market returns. A $30,000 loan over 5 years could cost you $50,000-$100,000 in lost retirement growth depending on market performance.

What's the difference between a 401(k) loan and a 401(k) withdrawal?

A 401(k) loan must be repaid with interest, doesn't trigger taxes or penalties if repaid on time, and the interest goes back into your account. A withdrawal is permanent—you don't repay it, and it's immediately subject to income tax plus a 10% penalty if you're under 59½. Loans are generally better if you need short-term funds and can repay them, while withdrawals are for true financial emergencies.

Can I have multiple 401(k) loans at the same time?

It depends on your plan rules. Some plans allow multiple loans, but the total outstanding balance cannot exceed the IRS limits (50% of vested balance or $50,000). The calculation becomes complex: if you have an existing loan, your new maximum is reduced by the highest outstanding balance in the past 12 months. Check with your plan administrator for specific rules.

How long do I have to repay a 401(k) loan?

The IRS requires 401(k) loans to be repaid within 5 years (60 months) unless the loan is used to purchase your primary residence. Residential loans can have longer terms, sometimes up to 15-30 years. Payments must be made at least quarterly and in substantially equal amounts including both principal and interest. Most plans use payroll deductions for convenience.

Should I take a 401(k) loan or explore other options?

401(k) loans should be a last resort. Consider alternatives first: emergency fund, HSA for medical expenses, 0% APR credit cards for short-term needs, personal loans from credit unions (often 7-18% APR), or home equity loans/lines of credit if you're a homeowner. Only use a 401(k) loan if you have stable employment, can repay within 1-2 years, and have exhausted better options. The risk of job loss and double taxation makes them expensive.

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