Compound Interest Calculator for Retirement — 401(k), Roth IRA & Long-Term Growth

Enter your current retirement savings, monthly contribution, employer match, expected return, and years until retirement to see your projected balance. A $500/month 401(k) contribution with a 50% employer match at 7% grows to $854,000 in 30 years. Without compound interest, that same money would only be $270,000.

Retirement Growth Scenarios

Starting from $0 today, contributing monthly at 7% average annual return:

Monthly Contribution	+ Employer Match	Total Monthly	After 20 Years	After 30 Years	After 40 Years
$250 (5% of $60K)	$125 (50% match)	$375	$195,347	$456,741	$980,488
$500	$250 (50% match)	$750	$390,695	$913,483	$1,960,976
$500	$0 (no match)	$500	$260,464	$608,985	$1,307,317
$1,000	$500 (50% match)	$1,500	$781,390	$1,826,965	$3,921,953
$1,625 (max 401k)	$812 (50% match)	$2,437	$1,269,396	$2,968,574	$6,373,174
$583 (max Roth IRA)	$0 (no match in IRA)	$583	$303,779	$710,478	$1,525,540

The Employer Match: Free Money You Cannot Ignore

If your employer offers a 401(k) match and you are not contributing enough to get it, you are leaving free money on the table:

Your Contribution	Employer Match (50%)	Free Money Per Year	Free Money Over 30 Years (at 7%)
$0 (not participating)	$0	$0/year	$0
3% of $60K ($150/mo)	$75/month	$900/year	$91,370
5% of $60K ($250/mo)	$125/month	$1,500/year	$152,284
6% of $60K ($300/mo)	$150/month (typical cap)	$1,800/year	$182,741

At a typical 50% match up to 6% of salary, not participating costs you $182,741 over 30 years. That is $1,800/year of free money, compounded over decades. Contribute at least enough to max the match.

401(k) vs Roth IRA — Tax Comparison

Feature	401(k) / Traditional IRA	Roth IRA
Tax on contributions	\u2713 Pre-tax (reduces income now)	\u2717 After-tax (no deduction)
Tax on growth	Deferred — taxed at withdrawal	\u2713 Tax-free
Tax on withdrawals	\u2717 Taxed as ordinary income	\u2713 Tax-free
2026 contribution limit	$23,500 (401k) / $7,000 (IRA)	$7,000
Employer match available	\u2713 Yes (401k)	\u2717 No
Income limits	None (401k) / Phase-out for IRA deduction	$161,000 single / $240,000 married
Required minimum distributions	\u2717 RMDs at age 73	\u2713 No RMDs (Roth IRA)
Best if you expect	Lower tax rate in retirement	Higher tax rate in retirement

Pair These Tools Together

• Compound Interest Calculator — model any retirement scenario
• Salary Calculator — see your income to plan contribution percentages
• Percentage Calculator — calculate contribution rates and match percentages
• Mortgage Calculator — balance mortgage and retirement savings

Honest Limitations

Retirement projections assume a constant return rate, which does not reflect real market volatility. A 7% average does not mean 7% every year — some years will be +25%, others -20%. Sequence-of-returns risk (bad years early in retirement) can significantly impact outcomes. These projections also do not account for inflation (use 5% instead of 7% for inflation-adjusted estimates), fees (which reduce net returns by 0.1-1.0%), or tax implications (which vary by account type and withdrawal strategy). Use these numbers as directional guidance, not precise predictions.