A 401(k) loan calculator compares interest paid to yourself against market growth while shares are out of the plan.
Ein Kredit aus dem eigenen 401(k)-Mitarbeiterdepot wirkt verlockend: Keine Schufa-Abfrage, niedriger Zinssatz und die Zinsen fließen zurück ins eigene Vermögen. Der Haken liegt im Zinseszins-Verlust: Das entnommene Kapital nimmt während der Kreditlaufzeit nicht an Marktwertsteigerungen teil. Zudem erfolgt die Rückzahlung aus bereits versteuertem Einkommen, das im Alter erneut versteuert werden muss (Doppelbesteuerungsfalle).
Echte Kosten des 401(k)-Darlehens
Ein 401(k)-Darlehen zahlt Zinsen an sich selbst, entzieht aber investiertes Kapital dem Markt. Rendet der Fonds 8 % und das Darlehen 5 %, bleibt Opportunitätskosten positiv.
Jobwechsel erfordert oft schnelle Rückzahlung—steuerpflichtige Distribution bei Nichtzahlung möglich.
Mit Privatkredit oder HELOC vergleichen—Plandetails und Origination Fees variieren.
Leitfaden, Beispiele und Methodik
How to use this 401(k) loan cost calculator
Model borrowing from your 401(k): loan amount, interest rate paid back to yourself, lost market growth on borrowed funds, job-change repayment risk, and alternative borrowing cost. US plans often allow loans up to 50% of vested balance (IRS limits apply).
Example (USD)
Item
Example
Risk
Loan
$20,000 from 401(k)
Not invested while outstanding
Opportunity cost
7% market return forgone
Can exceed loan interest
Job change
Balance due quickly
Potential tax + penalty if default
How we calculate
We compare ending balance if you left funds invested versus repaying a plan loan with stated interest, plus optional alternative loan APR. Plan rules, double taxation myths, and fees vary—read your SPD and talk to HR.
Common mistakes
Treating 401(k) interest paid to yourself as ‘free money’ while missing market gains.
Borrowing for discretionary spending instead of true emergencies.
Ignoring repayment if you leave the employer.
Reducing contributions while repaying the loan and missing the employer match.
IRS limits and plan rules (overview)
The IRS generally caps 401(k) loans at the lesser of $50,000 or 50% of your vested account balance (with additional rules for low balances). Not every plan offers loans; some allow two outstanding loans or restrict purpose. Maximum term is often five years except for primary residence. Your Summary Plan Description lists fees, default treatment, and whether you may continue contributions while repaying.
Job change and default risk
If you terminate employment with an outstanding loan, many plans require full repayment within 60–90 days. Unpaid balance may be treated as a distribution—ordinary income tax plus 10% early withdrawal penalty if under age 59½ (exceptions apply). That risk often exceeds the spread between plan loan rate and bank personal loan APR.
Alternatives to compare
Before borrowing from retirement, compare: taxable emergency fund, HYSA, 0% promo credit card (if payoff plan exists), home equity line (if secured debt is acceptable), or unsecured personal loan. Each avoids removing dollars from tax-advantaged compounding. Enter an alternative APR in this calculator to see if external borrowing costs less on a risk-adjusted basis.
Sometimes for short-term liquidity with stable employment, but opportunity cost and job-change repayment risk are real. Compare to a personal loan or emergency fund first using this calculator.
Was passiert bei Jobverlust mit einem laufenden 401k-Kredit?
Bei Kündigung verlangt das Finanzamt meist die sofortige Tilgung der Restschuld innerhalb weniger Monate. Andernfalls gilt der Betrag als vorzeitige Entnahme, was Einkommensteuer und stolze 10 % Strafgebühr nach sich zieht.