If you have ever watched a retirement balance jump upward in the later years of a projection and wondered where the money came from, you have already seen the two halves of every growth story: the dollars you actually put in, and the earnings those dollars quietly produce while they sit invested. The Roth IRA sits on the most attractive end of that spectrum, because every one of those dollars grows without triggering annual tax, and qualified withdrawals come out tax-free. This calculator projects how a Roth IRA balance builds from a starting balance plus yearly contributions, shows how much of the final figure is contributions versus investment earnings, and re-states the result in today's purchasing power after inflation. It is a planning tool, not a guarantee, but the underlying math is simple, transparent, and worth understanding line by line.
The basic future-value math of a Roth IRA
Under the hood, a Roth IRA is just a basket of investments, and the basket follows the same compound-growth equation used by any investment projection. Each year the entire balance earns the expected return; the next year that return is earned on a slightly larger balance; and the chain repeats every single year until retirement. The calculator captures this with the standard future-value formula:
FV = B × (1 + r)^n + C × [((1 + r)^n − 1) / r]
In that formula, B is the current Roth balance, C is the annual contribution, r is the annual return expressed as a decimal (so 7% becomes 0.07), and n is the number of years between the current age and the target retirement age. The first term grows the money you already own. The second term adds up the future value of a stream of yearly contributions, each one earning a share of the compounding. Because contributions are assumed to land at the end of each year, the annuity term uses the ordinary-annuity shape rather than the annuity-due version, a small distinction that keeps the default output exactly aligned with how most annual savings plans actually work.
Take the default inputs as a sanity check. A 30-year-old with $10,000 saved and $7,000 contributed each year, earning 7% until age 65, compounds the lump sum to about $106,800 while the annuity of contributions grows to roughly $967,700. The projected balance lands near $1.07 million. The contributions column says $245,000 was deposited over the 35 years; everything above that figure, about $829,000, is investment earnings. Those two numbers, contributions and earnings, are the crux of the entire calculator, and they appear again in the donut chart and in every year of the projection table.
Contributions versus earnings: why the gap widens
The single most instructive relationship in long-term projections is the widening gap between your own money and the wealth generated on top of it. In the first few years the balance line and the contributions-only line sit close together, because compounding has barely started. By year ten the gap is noticeable; by year thirty it dominates the picture, and in many projections the earnings total is three or four times larger than every dollar you ever contributed.
The reason is simple: contributions grow linearly, while compounded earnings grow exponentially. Every year the account adds the same flat contribution, but it also multiplies a balance that is itself growing. Interest earns interest, and the interest-on-interest compounds faster the longer the money stays invested. The two chart series in this calculator visualize exactly that: the gray contributors line climbs steadily, while the green balance line arcs upward, and the area between them is the pure value of giving your money time.
This is also why the milestone widget shows such uneven spacing. Hitting the first $100,000 can feel like an eternity because early earnings are small; crossing from $900,000 to $1,000,000 can take only a single strong year, because by then a typical year of 7% growth moves the entire balance by tens of thousands of dollars. The calendar does not speed up, but the math does, and the milestone list makes that visible.
Why the Roth wrapper matters
A Roth IRA is not a different kind of investment; it is a different kind of tax arrangement wrapped around ordinary investments. Because contributions are made with after-tax dollars, the IRS does not charge a tax bill when the money eventually comes out. Growth in the account is not taxed as it accrues, and qualified withdrawals after age 59½ with a five-year holding period are entirely tax-free, with no required minimum distributions during your lifetime.
Compare that chain against a plain taxable brokerage account holding the same stocks. In a taxable account, selling winners triggers capital gains tax, dividends are taxed as they are paid, and every rebalance can create a taxable event that quietly chips away at compounding. Over three or four decades those annual leaks compound into a meaningful difference, which is the reason financial writers call the Roth's tax-free growth the single most valuable feature in retirement saving.
The calculator keeps a marginal tax rate input for exactly this comparison. When you think through the math using your own bracket, the advantage of a Roth appears as the tax that a taxable account would have paid on the same earnings. The projection itself stays clean: because a Roth is tax-free, the projected balance is simultaneously the after-tax amount you would actually have available.
Reading the projection table and chart
The projection widget produces a year-by-year view of the account from today to the retirement age, usually stepping one row in five to avoid an endless list. Each row shows the invested total and the projected balance at that point in time, letting you watch the contributions line and the growing balance diverge. The chart summarizes the same story with two series: total balance and contributions-only. When a single large gap appears in the later years, that gap is the earnings bucket, and it is the number this calculator was designed to make visible.
A few practical pointers help when reading the table. First, look at the early rows to confirm the account grows slowly at first, which is normal and expected. Second, find the point where earnings officially overtake contributions, typically somewhere in the second or third decade of a 7% projection. Third, compare the final nominal balance against the inflation-adjusted value to understand how much purchasing power the same dollars will realistically carry in retirement. None of those observations requires a finance degree, but each one changes how a saver thinks about the required contribution amount.
Inflation and today's dollars
Nominal balances are exciting, but prices move too. The inflation-adjusted output in this calculator divides the projected balance by the cumulative growth of inflation over the same years, converting the future figure into today's buying power. If a projection shows $1.5 million nominal in 35 years and inflation averaged 3%, the same figure is only worth about $530,000 in today's purchasing power. That conversion is not a pessimistic trick; it is the honest way to compare the future number against today's living costs and decide whether the savings plan is large enough.
Because the calculator holds inflation constant for the whole projection, treat the adjusted figure as a single scenario rather than a precise prediction. Inflation jumps around in the real world, and the true answer depends on actual price growth year by year. Still, the banner and the adjusted output do their job: they stop a saver from being hypnotized by a seven-figure nominal number without checking what those dollars can actually buy.
Contribution limits and planning rules
Contribution limits shape what is possible inside any Roth projection. For the 2026 tax year the standard annual limit is $7,500 for savers under age 50, and $8,600 for those 50 and older, thanks to the catch-up provision. The limit applies across all of your traditional and Roth IRAs combined, and eligibility phases out at higher income levels, so the practical maximum depends on your filing status and modified adjusted gross income. The calculator accepts any annual amount up to $30,000 so you can test whether you plan to save the full limit, the base limit, or a smaller achievable figure.
A common question the default inputs do not answer directly is whether to prioritize a Roth IRA over a 401(k) or traditional IRA. Many planners suggest this loose order: contribute enough to any 401(k) to capture the employer match, consider a Roth IRA for the tax-free growth, and only then return to a 401(k) for additional pre-tax savings. The deciding factor is usually your current versus expected future tax bracket. Pay tax now when your rate is low and withdraw tax-free later if you expect to be in the same or a higher bracket; choose pre-tax accounts if retirement income is likely to be much lower than today's earnings.
Common pitfalls when projecting Roth growth
- Overly optimistic returns. Using 10% or 12% across four decades produces impressive totals that most portfolios will not actually deliver; a diversified mix of stocks and bonds more realistically averages 6% to 8%.
- Ignoring fees. The projection assumes the investments are free to hold. Expense ratios, advisory fees, and trading costs quietly reduce the effective return and compound over time.
- Flat contributions forever. Contributions tend to rise with income, while this model assumes a constant annual amount for the whole period.
- Confusing nominal and real. Reading only the nominal balance and ignoring the inflation-adjusted output overstates purchasing power at retirement.
- Changing the inputs to avoid the answer. The tool is an estimate; nudging the return upward to reach a target number defeats the purpose of a plan.
Who this calculator is for
The Roth IRA calculator fits anyone who saves in a Roth IRA, plans to open one, or is comparing account types for retirement. Young savers in low brackets benefit most from seeing how even a modest base limit compounds into a large tax-free sum by retirement age. Mid-career savers can test whether increasing annual contributions meaningfully shortens the road to their milestone targets. Retirees planning conversions or withdrawals can use the inflation-adjusted figure to sanity-check whether the nominal balance will actually fund their lifestyle. In every case the outputs are planning estimates for informational purposes, not a personalized fiduciary recommendation.
Putting the projection to work
Start by entering an honest current age, retirement age, starting balance, and the annual contribution you realistically expect to save. Then run the projection once at a conservative return and again at a more aggressive one to see the range of outcomes side by side. Check the gap between contributions and earnings to understand which half is doing the heavy lifting in your plan, and note the inflation-adjusted number so the final balance is measured in the same units as today's expenses. Adjust the annual contribution until the projected balance lands in the range that supports your retirement income goal, then re-run this calculator at least once a year as your income, balances, and contribution limits change.
Roth savings reward two decisions above all others: starting early and staying invested. Every extra year in the projection lets compounding do more of the work, which is why the same rate of return produces wildly different results depending purely on the starting age. The tables and charts in this calculator make that arithmetic visible, turn an abstract advantage into a sequence of understandable numbers, and help a saver convert a vague intention to contribute into a concrete, achievable plan.
Disclaimer
Results are provided as estimates for informational purposes only and may be inaccurate. Always verify outcomes with a qualified professional before making financial or personal decisions based on these calculations.