Starting now or later:
compare deposits and growth

What this comparison actually measures

Changing the start date while holding the end age and annual deposit fixed changes the number of deposits as well as their growth periods. It is not a same-total-contributions comparison, and it cannot establish that time always matters more than the amount saved.

With a positive constant return, the earlier deposits have longer to grow. With a negative return, earlier deposits also experience more losses. Neither assumption describes a guaranteed path. The model does not test larger later contributions, an existing balance, employer contributions or a different end age for the two scenarios.

A worked example you can reproduce

Set the start age to 50, end age to 65, annual deposit to $6,000, nominal return after fees to 5%, and delay to five years. With $0 initially and year-end deposits, starting now gives 15 deposits totaling $90,000 and a balance of about $129,471. Waiting gives 10 deposits totaling $60,000 and about $75,467.

The approximately $54,004 balance difference comprises $30,000 fewer deposits and about $24,004 less modeled growth. It is not all “lost compound interest.” At 0%, the difference is exactly $30,000: just the missing deposits.

How the math works

For each year, grow the previous balance by the assumed return, then add the deposit. For n deposits of C at return r, the formula is C × ((1 + r)ⁿ − 1) ÷ r. At r = 0, use C × n. Starting later uses max(0, end age − start age − delay) deposits.

All dollar inputs and outputs here are nominal. No inflation conversion occurs. Equal nominal deposits do not keep their purchasing power if prices rise. Reduce a gross return assumption for costs before entering it; the tool does not subtract fees separately.

Check the real-world rules separately

For 2026, the $7,500 base IRA ceiling plus the $1,100 age-50 catch-up gives $8,600, subject to eligibility. Regular Traditional and Roth IRA contributions share the annual limit. The tool does not check qualifying compensation, Roth modified adjusted gross income, other IRA contributions, or legal limits in future years. Use the contribution rules and the age/income ceiling checker; the latter is not exact remaining deposit room.

A balance is not necessarily money you can withdraw tax-free today. Qualified Roth distributions generally require the five-tax-year period plus age 59½ or another qualifying condition. Regular contributions and conversions follow different ordering and additional-tax rules. See the Roth clocks before interpreting an ending value as spendable earnings.

Choose the next question—not the biggest result

For compensation, cash flow and access checks, read Roth IRA for late starters. For changing contribution assumptions, inflation and simulated outcomes, use the Growth Projector. It uses beginning-of-year deposits, unlike this tool, so matching the other inputs will not reproduce these balances. Its simulated percentiles are not measured probabilities of your success.

This is an educational illustration, not tax, legal or investment advice. It does not determine whether you have enough to retire, select investments or model retirement spending. Actual returns can fall outside the entered range.

Sources and calculation basis

• IRS Notice 2025-67: 2026 IRA base and catch-up amounts.
• IRS Publication 590-A (2025), chapters 1–2: compensation, shared IRA limits and Roth eligibility. Use the notice for 2026 amounts.
• IRS Publication 590-B (2025), chapter 2: qualified Roth distributions and ordering rules.
• SEC Investor.gov: Understanding fees. Results use the disclosed year-end recurrence, not a historical return dataset.