401(k) Calculator

Model employee deferrals, employer matching, age-based catch-up contributions, and investment growth separately. The projection starts with 2026 federal limits, lets future limits grow only by an explicit assumption, and deposits contributions monthly.

Inputs

Instant calculation

Required

Current balanceUSDx ≥ 0

Annual salaryUSDx ≥ 0

Employee contribution%0 ≤ x ≤ 100

Age at the end of 2026years0 ≤ x ≤ 100; x ∈ ℤ

Employer match rate%0 ≤ x ≤ 500

Salary eligible for match%0 ≤ x ≤ 100

Prior-year FICA wages from this plan sponsorFor the 2026 contribution year, use 2025 FICA wages from the employer sponsoring this plan. Wages from unrelated employers are not combined.USDx ≥ 0

Plan permits Roth catch-up contributions

Annual salary growth%-100 ≤ x ≤ 100

Assumed annual IRS limit growth after 2026Future IRS limits are unknown. Enter an explicit assumption; 0% keeps all limits in 2026 nominal dollars.%0 ≤ x ≤ 20

Annual return%-99 ≤ x ≤ 100

Years to contributeyears1 ≤ x ≤ 80; x ∈ ℤ

Result

Instant calculation

Projected ending balance: $922,679.48
Employee contributions: $256,242.40
Employer contributions: $76,872.72
Regular employee deferrals: $256,242.40
403(b) service catch-up contributions: $0.00
Age-based catch-up contributions: $0.00
Projected investment growth: $539,564.36
Age catch-up allocated to Roth: $0.00
Projected Roth catch-up balance: $0.00
Catch-up excluded because Roth catch-up is unavailable: $0.00

Important

Starts with the 2026 $24,500 elective-deferral limit, $72,000 annual-additions limit, $8,000 age-50 catch-up, and $11,250 age-60-to-63 catch-up. Future limits and the $150,000 Roth catch-up wage threshold grow only by the explicit 0% assumption. Contributions are spread evenly across 12 month-end deposits rather than receiving a full year of growth. Catch-up contributions are modeled outside the annual-additions limit. Beginning with 2026, age-based catch-up contributions are assigned to the Roth bucket when projected prior-year FICA wages from this sponsor exceed the modeled threshold. If the plan is marked as not permitting Roth catch-up, that otherwise eligible catch-up is excluded rather than mislabeled as pre-tax. Plan terms, eligibility, vesting, payroll timing, Roth catch-up requirements, taxes, and fees can differ.

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How to use this calculator

Review current IRS limits, catch-up eligibility, plan compensation definition, vesting, match cap, investment risk, tax treatment, and fee disclosures.

Read projected balance, regular and age-based employee deferrals, required Roth catch-up bucket, unavailable Roth catch-up amount, employer contributions, and investment growth.

Formula

Regular deferral is capped at the modeled $24,500 limit; eligible age catch-up is added separately. Employer match follows the entered rate and salary cap, regular additions observe the modeled $72,000 limit, and cash flows enter monthly.

Worked example

On $60,000 salary, a 6% deferral is $3,600 and a 50% match through 6% adds $1,800 before annual-limit and eligibility checks; both are deposited across 12 months.

Assumptions and limits

For 2026, prior-year FICA wages from this plan sponsor above $150,000 require age-based catch-up contributions to use Roth treatment when the plan offers catch-up. The model excludes rather than mislabels the catch-up when Roth catch-up is marked unavailable.
401(k) Calculator treats the entered values as estimates and does not infer missing project, account, or personal details.
Calculations retain working precision except where the cited method requires an intermediate rounding step; displayed values are then formatted separately. Source rules and dated rates must be rechecked when they change.

Sources

Internal Revenue Service: 401(k) Plan Overview401(k) contributions, elective deferrals, and plan concepts. Reviewed 2026-08-14.
Internal Revenue Service: Retirement Topics: Catch-Up Contributions2026 age-based catch-up limits and the prior-year wage test for required Roth catch-up treatment. Reviewed 2026-08-14.
U.S. Securities and Exchange Commission: Compound Interest CalculatorCompound-growth inputs and future-value concepts. Reviewed 2026-08-14.
Internal Revenue Service: 401(k) and profit-sharing plan contribution limitsOfficial formula or method source used by this calculator. Reviewed 2026-08-14.

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Verification

How this calculator is checked

Trust comes from reproducible evidence, not model confidence. You can inspect the formula, assumptions, worked example, and cited sources on this page.

Versioned calculationFormula logic is kept separate from the interface and covered by automated registry and behavior checks.
Cited evidenceSources linked for independent checking: 4.
Transparent AI useAI may assist drafting or adversarial review. Agreement between models is not proof, and no human expert review is claimed unless a named reviewer is shown.

Frequently asked questions

How does the 401(k) Calculator work?

What information should I enter in the 401(k) Calculator?

Enter current balance, salary, employee rate, age, employer match formula, prior-year FICA wages from this sponsor, plan Roth catch-up availability, salary and future-limit growth, annual return, and years, then verify current IRS limits, catch-up eligibility, plan compensation definition, vesting, match cap, investment risk, tax treatment, and fee disclosures.

What should I verify before using this 401(k) Calculator result?

For 2026, prior-year FICA wages from this plan sponsor above $150,000 require age-based catch-up contributions to use Roth treatment when the plan offers catch-up. The model excludes rather than mislabels the catch-up when Roth catch-up is marked unavailable.

Last updated 2026-08-25 · 2026-monthly-retirement-projection-v4 · content-2026-08-14 · Published by YunFanLabs

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