401(k) Retirement Savings Calculator
See how a current balance and regular contributions could grow before retirement.
Example estimate
Illustrative balance at retirement
$521,008
- Initial balance plus contributions
- $250,000
- Years of contributions
- 25
An illustrative calculation. Review the assumptions below before using the result.
Monthly contributions compound at month-end
The current balance grows at a constant monthly rate derived from the real annual rate. Equal monthly contributions are added at month-end. The result stays in today’s purchasing power. This scenario does not enforce annual IRS contribution limits or model taxes, market sequence, changing salary or fees.
Questions, answered.
Does this use my personal records?
No. Enter amounts or assumptions only. The site cannot retrieve an SSA earnings record, bank account, pension award or tax return.
Can I calculate with JavaScript turned off?
Yes. Each form sends a standard GET request and PHP calculates the result. JavaScript only improves the update and consent experience.
Why do the official numbers differ from my result?
Individual eligibility, exact dates, rounding, deductions and rules omitted from a simplified scenario can change the amount. Check the source and your own agency notice.
Can I print the calculation?
Use your browser’s print command. The inputs, result and assumptions remain; navigation and consent controls are removed from the printed view.
Check the sources.
Data checked October 1, 2026.