401(k) Calculator
Project future 401(k) balance from starting savings, monthly contributions, employer match, expected return, and years until retirement.
Deferral growth milestones (illustrative)
Starting balance $25,000, $500/mo deferral, 50% employer match, 7% average return—compounded monthly.
| Years saving | Projected balance |
|---|---|
| 10 years | $180,055 |
| 20 years | $491,663 |
| 30 years | $1,117,891 |
Educational projection—not investment, tax, or retirement advice. Actual returns, fees, and withdrawal rules differ by plan and age.
Suggested next step
Formula & how the math works
The projection compounds monthly. Convert your annual expected return r into a monthly rate i = r / 12. Each month the prior balance grows by (1 + i), then employee deferral and employer match are added.
Employer match is modeled as a percentage of your monthly deferral (for example, 50% match on $500 is $250). The tool does not enforce IRS annual limits—enter contributions you believe are plan-legal.
Ending balance after n years (12n months) is the result of that loop. Total contributions are tracked separately so you can see growth versus dollars you and your employer put in.
B_{t+1} = B_t × (1 + r/12) + deferral + (deferral × match%)FAQ for this calculator
- Does this include IRS contribution limits?
- No. Enter monthly deferrals you believe fit employee and catch-up limits for your age and plan year. The model will happily project illegal totals—you must cap inputs yourself.
- How is vesting handled?
- Employer match is assumed fully vested. If your plan uses a graded or cliff schedule, reduce the match percent or treat unvested dollars as zero until you confirm the schedule.
- Does it model Roth vs traditional tax treatment?
- No. The projected balance is a pre-tax style gross figure. Roth contributions change today’s paycheck tax, not the compounding loop itself—run paycheck tools separately if you need take-home impact.
- Can I model negative or low returns?
- Yes. Annual return can be set from about −20% to 20% so you can stress-test flat or down markets instead of assuming a smooth 7% every year.
- Is employer match applied before or after growth each month?
- Growth is applied to the prior balance first, then deferral and match are added. Real payroll timing varies; this ordering is a common planning simplification.
- Should I treat this as financial advice?
- No. It is an educational projection. Confirm plan rules, fees, investment mix, and tax strategy with your plan documents and a qualified advisor.
How to use the 401(k) projection calculator
Each month the balance grows by the monthly return rate, then your contribution plus employer match is added.
- Enter current 401(k) balance.
- Set monthly deferral and employer match percent.
- Pick expected return and years until retirement.
- Tap Calculate to project ending balance, total contributions, and implied growth.
When to use this calculator
- Seeing how raising contributions affects retirement.
- Comparing 50% vs 100% employer match scenarios.
- Early-career vs mid-career projection checks.
- Stress-testing a lower return (for example 4–5%) before you rely on an optimistic 8–10% path.
Examples & walkthrough
- $25k now, $500/mo, 50% match, 7% return, 30 years → balance well above contributions alone.
- Higher return assumptions inflate projections—stress-test with lower rates too.
- Try doubling the monthly deferral while holding return fixed to see how cash flow beats rate guessing.
Quick comparison
Same starting balance and years; only deferral or match changes. Numbers are illustrative—rerun with your inputs.
| Scenario | Monthly deferral + match | What usually changes |
|---|---|---|
| Baseline saver | $400 + 50% match | Steady path; match is meaningful but not maxed |
| Raise deferral | $600 + 50% match | Largest lift for most mid-career balances |
| Fuller match | $400 + 100% match | Free money if your plan allows—often beats chasing return |
| Conservative return | $500 + 50% match @ ~4% | Lower ending balance; useful downside case |