Start with your plan
How to use this 401(k) calculator
- 1Enter your age, retirement age, salary, and current balance.
Use the age you turn during 2026 so the calculator can select the applicable employee limit.
- 2Enter your contribution and employer match.
Use the simple formula shown in your plan materials, such as a 50% match up to 6% of eligible pay.
- 3Test return, fee, inflation, and growth assumptions.
Open the advanced section to change the visible defaults and compare scenarios.
What your results mean
The projected balance combines the starting balance, modeled employee contributions, estimated employer contributions, and investment growth. The figure in today’s dollars removes the effect of the entered inflation rate.
Unused employee room compares the planned 2026 contribution with the estimated employee deferral limit. It does not track payroll deposits already made, correct an excess contribution, or guarantee that your plan accepts the full amount.
Transparent model
401(k) formula and calculation method
- Employer match = match rate × min(employee deferral, match-limit percentage × eligible compensation).
- Net annual return = expected annual return − annual plan and investment fees.
- Monthly return =
(1 + net annual return)^(1/12) − 1.
The model assumes even payroll contributions, a fully vested match, and an annual true-up, then spreads employee and employer amounts evenly across 12 end-of-month deposits. Salary and projected future limits change only at year boundaries. Compensation used to calculate the employer match is capped at the 2026 compensation limit. Actual payroll timing, true-up rules, and vesting can differ.
Worked example
With a $100,000 salary, a 6% employee contribution, and a 50% match up to 6% of salary, the employee contributes $6,000 and the estimated employer match is $3,000. With a $0 starting balance, 0% return, no fees, and one projection year, the ending balance is $9,000.
2026 401(k) limits used
- The basic employee elective-deferral limit is $24,500.
- A plan-permitted catch-up contribution for participants age 50 or older can add $8,000. Participants who turn 60 through 63 use the higher $11,250 catch-up instead.
- The defined-contribution annual-additions limit is $72,000, excluding permitted catch-up contributions.
- The compensation limit used for plan contribution calculations is $360,000.
- Non-catch-up employee and employer additions cannot exceed the lesser of the annual-additions limit and compensation.
Limits after 2026 are not enacted in this calculator. The engine grows the 2026 amounts by the future-limit assumption so the long-term projection can apply a visible, consistent scenario.
Assumptions and limitations
- Employer contributions are spread evenly across the year and use a full-year match calculation. Vesting is not modeled, so confirm how much of an employer contribution you would keep under your plan.
- Actual plan eligibility, payroll timing, vesting, catch-up availability, and match formulas can differ. Your plan document controls.
- The model does not calculate loans, early withdrawals, taxes, traditional-versus-Roth treatment, or nondiscrimination testing.
- The model does not apply the 2026 Roth catch-up designation for certain participants whose prior-year wages from the plan sponsor exceeded $150,000. That rule depends on plan features and facts outside this calculator.
- Returns, fees, inflation, salary growth, and future contribution-limit growth stay constant within the scenario. Actual values vary.
Common questions
Frequently asked questions
How does a 401(k) employer match work?
The employer contributes according to the plan formula when you make an eligible employee contribution. This calculator supports a single match rate up to a percentage of eligible compensation. Your plan document controls payroll timing, vesting, exclusions, and any more complex tiers.
What are the 2026 401(k) contribution limits?
The basic employee deferral limit is $24,500. A plan-permitted catch-up is $8,000 for eligible participants age 50 or older. Eligible participants ages 60 through 63 use the higher $11,250 catch-up instead. Other plan and compensation limits can also restrict contributions.
How much should I contribute to get the full employer match?
For the formula modeled here, contribute at least the match-limit percentage of eligible compensation, subject to employee and plan limits. The result card shows whether the entered contribution reaches that threshold.
How do 401(k) fees affect the projection?
The calculator subtracts the entered annual fee rate from the expected annual return. Even a modest recurring fee can have a large long-term effect because it reduces the return applied each month.
Does this work for Roth 401(k) contributions?
It can illustrate account growth because the same contribution and match mechanics may apply, but it does not compare current tax deductions, Roth tax treatment, qualified distributions, or plan-specific Roth rules.
What does this calculator leave out?
It leaves out taxes, loans, early withdrawals, changing investment allocations, market volatility, complex match tiers, nondiscrimination testing, and plan-specific restrictions.
Sources
- IRS: 401(k) limit increases to $24,500 for 2026 (accessed July 27, 2026)
- IRS: Cost-of-living increases for retirement-plan limits (accessed July 27, 2026)
- IRS: 401(k) and profit-sharing plan contribution limits (accessed July 27, 2026)
- IRS: Catch-up contributions (accessed July 27, 2026)
- US Department of Labor: Understanding your retirement plan fees (accessed July 27, 2026)