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Utilnivo

Finance

401(k) Calculator

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  • No signup

Enter current balance, monthly contribution, employer match percentage, expected return, and years to estimate projected balance, total contributions, employer match, and investment growth.

100% Client-Side

Your data never leaves your computer.

How to use this tool

1. Enter your current 401(k) balance. 2. Enter your monthly employee contribution. 3. Enter employer match as a percent of your contribution (for example 50 for half). 4. Set expected annual return and years until retirement. 5. Click Calculate and review projected balance, employee vs employer contributions, and growth.

Worked example

Example: with about $25,000 saved today, roughly $500/month employee contributions, a 50% employer match, near 7% average annual return, and a 20-year horizon, many plans project a balance in the low-to-mid hundreds of thousands of dollars—your plan rules and market returns will differ.

How it works

Projects a 401(k) balance with monthly compounding. Employee contributions are added each month; employer match is calculated as a percentage of the employee contribution and added monthly. Starting balance grows with the same monthly return. IRS annual limits, vesting schedules, catch-up contributions, plan fees, and tax treatment are not modeled.

Limitations

Employer match rules, IRS limits, and catch-up contributions are simplified. Consult your plan documents for exact eligibility.

Privacy and file handling

Your data is processed in your browser and is not uploaded to our server.

Accuracy & methodology

This section documents how the calculator works, what it leaves out, and when results were last reviewed. Figures are educational estimates—not professional advice—and are not labeled "current" unless tied to automatically updated reference data.

Formula source or methodology
Monthly compounding at annual return ÷ 12. Starting balance grows each month. Employee contribution is deposited monthly; employer match = employee contribution × match%. Total monthly deposit uses the future value of an ordinary annuity (payments at end of month) plus FV of starting balance.
Jurisdiction
United States (educational projection only)
Unit system
US dollars; monthly contribution and balance fields
Rounding method
Currency amounts round to two decimal places (half up via Math.round × 100 / 100).
Assumptions
  • US 401(k) planning context; user-entered return rate is constant for the full horizon
  • Employer match is a flat percentage of the employee contribution every month
  • Same monthly return applies to existing balance and new deposits
  • Contributions continue uninterrupted for the entire period
Known omissions
  • Not tax, legal, investment, or lending advice. Confirm material decisions with qualified professionals.
  • 2026 IRS contribution limits ($23,500 elective deferral; $7,500 catch-up age 50+; $70,000 combined annual additions under §415(c)) — limits are not enforced in the model
  • Employer match annual caps, true-up provisions, and vesting schedules
  • Plan administrative fees and fund expense ratios
  • Inflation adjustment of future dollars (nominal dollars only unless stated)
  • Income tax on withdrawals (pre-tax vs Roth treatment)
  • Required minimum distributions (RMDs) and early withdrawal penalties
  • Beginning- vs end-of-pay-period contribution timing beyond end-of-month annuity model
  • Automatic enrollment escalation or bonus/true-up deposits
Test cases (automated)
  • Valid inputs ($25k balance, $500/mo employee, 50% match, 7% return, 20 years) produce a positive projected balance
  • Negative balance, negative contribution, or invalid match % are rejected
Version & last verified

Logic version 1.0. Content and formulas last verified .

Important notice

Results are estimates for educational purposes and are not financial advice. Contribution limits, vesting, taxes, and fees are simplified or omitted. Consult a qualified financial professional for personal guidance.

Frequently asked questions

How is employer matching calculated?

Employer match is applied as a percentage of your monthly employee contribution. For example, 50% match on $500/month adds $250/month from the employer before growth is applied.

Does this include annual IRS contribution limits?

No. The calculator does not cap employee or employer deposits at IRS 401(k) limits, catch-up amounts, or plan-specific rules.

Are contributions assumed to happen monthly?

Yes. Employee and employer amounts are added every month and compounded at the monthly equivalent of your annual return.

Does the result include investment fees?

No. Plan administration fees, fund expense ratios, and advisory costs are not subtracted from the projection.

What return should I use?

Many long-term retirement models use a conservative real or nominal return such as 5–7%, but actual market returns vary. Use a range of scenarios rather than a single guess.

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