401k Contribution Limit Calculator: How to Max Out and What It Saves You

The 401k has two distinct advantages that compound on each other: the immediate tax deduction (you pay less this year) and the tax-deferred growth (no annual taxes on gains for decades). Together they produce outcomes impossible in a taxable brokerage account.

Here are the exact numbers for 2026.

2026 Contribution Limits

| Contribution Type | 2026 Limit | |------------------|-----------| | Employee pre-tax + Roth | $23,500 | | Catch-up (age 50-59 and 64+) | +$7,500 | | Catch-up (age 60-63, SECURE 2.0) | +$11,250 | | Total employee limit (50-59, 64+) | $31,000 | | Total employee limit (60-63) | $34,750 | | Total including employer contributions | $70,000 |

The $11,250 catch-up for ages 60-63 is a new provision from SECURE 2.0, allowing those nearing retirement an enhanced final catch-up.

The Immediate Tax Savings

Pre-tax 401k contributions reduce your taxable income dollar for dollar.

On $100,000 gross salary, maxing at $23,500:

| | Without Max 401k | With Max 401k | |--|-----------------|--------------| | Gross income | $100,000 | $100,000 | | 401k contribution | $0 | $23,500 | | Taxable income | $100,000 | $76,500 | | Standard deduction | -$15,000 | -$15,000 | | AGI taxed | $85,000 | $61,500 | | Federal income tax | $13,070 | $8,358 | | Tax savings | — | $4,712 |

Pre-tax 401k contributions at $100,000 income save $4,712 in federal taxes immediately. The effective cost of contributing $23,500 is $23,500 - $4,712 = $18,788 in reduced take-home pay.

Add state tax savings (at 5%): an additional $1,175. Total immediate tax savings: approximately $5,887.

The 30-Year Growth Comparison

$23,500/year invested for 30 years at 7% annual return:

In a pre-tax 401k:

• No annual taxes on dividends or capital gains
• Final balance at 30 years: $2,263,000
• Taxes owed on withdrawal (assume 22% in retirement): $497,000
• Net after-tax value: $1,766,000

In a taxable brokerage account:

• Annual tax drag on dividends (assume 1% yield, 15% tax): reduces effective return slightly
• Capital gains taxes on growth
• Effective net return approximately 6.2%
• Final balance at 30 years: $1,964,000 (pre-tax)
• After capital gains taxes: approximately $1,750,000

At these assumptions, the difference is close. The 401k wins primarily on deferring taxes and allowing full compound growth on the gross amount.

The real gap widens for high earners in high-tax states who drop to lower tax brackets in retirement. Contributing at 37% + 9% state = 46% combined rate and withdrawing at 22% + 5% = 27% produces enormous arbitrage.

The Roth 401k: When It Makes Sense

Since 2024, employer contributions to Roth 401ks are allowed. Roth 401k contributions use after-tax dollars but grow and withdraw tax-free.

Choose traditional (pre-tax) 401k when:

• Current marginal rate is higher than expected retirement rate
• Income is in peak earning years (35-55)
• State has income tax now but you plan to retire in a no-income-tax state

Choose Roth 401k when:

• Current income is lower (early career, career break)
• You expect to be in the same or higher bracket in retirement
• You want to avoid RMDs (starting 2024, Roth 401ks have no RMDs)
• You have a long runway (more years of tax-free compounding)

Many financial planners recommend contributing to both: traditional for the current deduction and tax diversification, Roth for tax-free retirement income.

How to Actually Max Out

$23,500/year = $1,958/month = $901/biweekly paycheck.

That is a significant portion of most salaries. The path to maxing out:

Income under $70,000: Maxing is difficult without compromising essential expenses. Prioritize enough to get the full employer match, then increase as income grows.

Income $80,000-$120,000: Maxing requires deliberate budget optimization. $1,958/month from a $6,000 take-home is 33% of take-home, which requires low housing costs or a dual income.

Income above $150,000: Maxing should be default. At $150,000 gross, $23,500 is 15.7% of gross income. Take-home after contribution and taxes is $8,500-$9,500/month, which is plenty for most budgets.

The Employer Match: The Most Important Number

Before chasing the $23,500 limit, capture every dollar of employer match. A 4% match on a $100,000 salary is $4,000 in free money annually — a 100% instant return.

Priority order:

1. Contribute enough to get full employer match
2. Max HSA if eligible ($4,300 individual or $8,550 family)
3. Max 401k to $23,500
4. Max IRA ($7,000)
5. Taxable brokerage

The employer match return dwarfs everything else. Never leave it on the table.

Frequently Asked Questions

What happens if I over-contribute to my 401k?

Excess contributions above the annual limit must be withdrawn by April 15 of the following year. The excess is taxable in both the contribution year and the withdrawal year (double taxation). Your plan administrator or payroll should stop contributions when the limit is reached, but errors happen. Monitor your contributions, especially if you changed jobs mid-year.

Can I contribute to both a 401k and an IRA?

Yes. The 401k and IRA have separate limits. You can max both ($23,500 + $7,000 = $30,500). IRA deductibility phases out at certain income levels if you have a workplace plan, but you can always contribute to a non-deductible IRA and execute the backdoor Roth.

Does my employer match count toward the $23,500 limit?

No. The $23,500 is your employee contribution limit. Employer contributions are additional, up to the $70,000 total limit. A $23,500 employee contribution + $6,000 employer match = $29,500 total, all within limits.