401(k) contributions, employer match and growth: a 2026 guide

A 401(k) projection combines what is already in the account, future employee contributions, an employer match, time, and an assumed investment return. The result is useful for planning, but it is not a promise of future performance.

401(k) contribution limits for 2026

The IRS applies more than one limit. The employee elective-deferral limit controls how much of your own pay you can defer. A separate overall annual-additions limit generally covers employee deferrals plus employer contributions and certain other additions. Your plan can also impose a lower limit.

These figures are specific to 2026 and can change in later years. SIMPLE 401(k) plans use different limits. If you participate in more than one plan, the interaction between limits can be more complicated than a single calculator input.

How employer matching works

An employer match is controlled by the plan, not by a universal formula. A phrase such as “50% of contributions up to 6% of salary” means the employer contributes fifty cents for each dollar you contribute, but only on the first 6% of eligible pay.

For an $80,000 salary, 6% of pay is $4,800. If the employee contributes at least that amount and the match rate is 50%, the estimated employer contribution is $2,400. Contributing 8% instead of 6% would increase the employee’s own deposit, but it would not increase that employer match unless the plan’s matching cap were higher.

Check vesting rules as well. Money you contribute is yours, but some plans require a period of service before all employer contributions are fully vested.

How the calculator estimates future value

The calculator first estimates the annual employee contribution as salary multiplied by the employee contribution rate. It then estimates the employer match using the lower of the employee contribution or the salary amount eligible for matching. The combined annual amount is divided into monthly deposits.

The existing balance and each monthly contribution are then grown using a monthly rate derived from the annual return entered. In simplified form:

This model assumes a steady salary, contribution rate, match formula, and return for the full period. Real accounts do not grow in a straight line. Markets rise and fall, salaries change, fees reduce returns, and contributions may pause.

Worked 401(k) example

Suppose an employee enters a current balance of $25,000, an $80,000 salary, an 8% employee contribution, a 50% employer match up to 6% of salary, 25 years, and a 7% annual return.

• Employee contribution: $6,400 per year.
• Estimated employer match: $2,400 per year.
• Total new contributions: $8,800 per year, or about $733.33 per month.
• Starting balance plus deposits over 25 years: $245,000 before growth.
• Projected balance under the calculator’s smooth 7% assumption: about $737,188.

The difference between $737,188 and $245,000 is projected growth, not guaranteed earnings. Running a cautious scenario at 4% and an optimistic scenario at 7% or 8% is more informative than relying on a single rate.

How to interpret the result responsibly

• Use today’s numbers as a baseline. Enter the contribution rate shown on your latest statement and the exact match described by your employer.
• Test at least three return assumptions. A lower-return scenario shows whether the plan still works if growth disappoints.
• Account for fees. If your expected return is before fees, the net return available to the account will be lower.
• Revisit salary and contribution changes. A raise does not automatically increase retirement saving if the contribution amount is fixed rather than percentage-based.
• Keep taxes separate. Traditional and Roth 401(k) contributions have different current and future tax treatment, which this balance projection does not calculate.

Questions and limitations

Does the calculator cap my contribution at $24,500?

No. It multiplies salary by the percentage entered. You must keep the input consistent with the applicable annual limit and your plan’s rules.

Is a 7% return a prediction?

No. It is a scenario assumption. Investment returns vary, can be negative, and depend on the investments, fees, timing, and market conditions.

Should an employer match be counted toward the employee-deferral limit?

Employer contributions are not part of the employee elective-deferral limit, but they generally count toward the separate overall annual-additions limit.