Retirement Calculator

How this is worked out

The pot is built month by month, not year by year, because contributions are monthly for almost everyone and annual compounding of a monthly contribution overstates the answer by roughly half a year of growth.

Each month's contribution goes in at the start of the month and earns that month's return — an annuity-due, which is how a payroll deduction actually behaves. The monthly rate is the twelfth root of the annual one, not the annual one divided by twelve:

monthly rate = (1 + annual return − charges)^1/12 − 1

Then the part almost every retirement calculator skips. A balance in 2058 is not money you can spend in 2058 dollars you understand, so every figure is also divided back:

today's money = balance ÷ (1 + inflation)^years

At 2.5% inflation over 32 years that divisor is about 2.2. It is why the page leads with $680,793 and treats $1,500,303 as the secondary figure: they are the same pot, and only one of them is in units you can price a grocery run in.

Charges come off the return before anything compounds, and because they are levied on the balance they grow as the balance does. Half a percent a year on a pot of this size is not half a percent of the answer — the working below shows the whole amount.

The income the pot supports is solved rather than assumed. Instead of applying a flat 4%, the calculator finds by bisection the first-year withdrawal that survives the number of years you entered when the withdrawal itself rises with inflation each year, then reports what percentage of the pot that turned out to be.

A worked example

The match is the only guaranteed return anybody gets

A 50% employer match on the first 6% of pay is an instant 50% return on that money, before it has been invested in anything. No fund, no strategy and no adviser offers that, and it is the one number in retirement saving that is not an assumption. In the example above the employer contributes $132,681 over the term, and the growth attached to it is a large share of the $1,057,260 of total growth.

The money is nonetheless left on the table routinely, usually by people who set a contribution percentage when they were hired and never revisited it after a raise. A match expressed as a percentage of pay quietly needs your contribution percentage to keep up; a match expressed in dollars does not. Checking which shape your plan uses takes one look at the summary plan description.

Vesting is the detail that catches people leaving a job. Employer contributions can be subject to a cliff schedule — nothing until three years, then all of it — or a graded one over up to six years. Your own contributions are always yours immediately. This projection assumes everything vests, so if you are within a year of a cliff, that is a figure to check before comparing offers.

The catch-up at 60 replaces the one at 50 — it does not stack

For 2026 the employee elective deferral limit under §402(g) is $24,500. From 50 you may add a catch-up of $8,000. From 60 to 63, SECURE 2.0 raises that catch-up to $11,250 — and this is the part that gets reported wrongly — it replaces the $8,000 rather than adding to it, and only if your plan has adopted it.

So the true ceilings are $24,500 under 50, $32,500 from 50 to 59, $35,750 from 60 to 63, and back to $32,500 from 64. A calculator that adds the two catch-ups together overstates the limit for a 61-year-old by $8,000, in the direction that produces an excess deferral and a corrective distribution.

Separately, §415(c) caps everything going into the plan in a year — your deferrals, the employer's money and any forfeitures — at $72,000. An IRA is a different allowance again at $7,500, with a $1,100 catch-up indexed for the first time in 2026, and Roth IRA eligibility phases out between $153,000 and $168,000 of modified AGI filing single, or $242,000 to $252,000 filing jointly.

Traditional or Roth is a bet on your future tax rate

A traditional contribution is deducted now and taxed on the way out. A Roth contribution is taxed now and comes out untaxed. If your tax rate were identical in both years the two would produce exactly the same after-tax result — the arithmetic is commutative, and the frequently repeated claim that one of them "grows tax-free" while the other does not is simply wrong about both.

What breaks the tie is the difference between your marginal rate today and your effective rate in retirement, and those are not the same measure. Contributions are deducted at the top of your income; withdrawals fill a bracket structure from the bottom, alongside a standard deduction. Someone in the 24% bracket while working can draw a substantial income in retirement at a blended rate well below that, which is the case for traditional. Someone early in a career, in a low bracket, expecting a much higher one later, has the case for Roth.

The genuinely asymmetric parts are elsewhere. Roth IRAs have no required minimum distributions during the owner’s lifetime, which matters for estate planning; traditional balances do. Roth contributions — not earnings — can be withdrawn at any time without tax or penalty. And a Roth balance is a hedge against tax rates being raised, which is a political question rather than a financial one. This calculator projects a pot; it does not know your bracket in either year, and the choice does not change the pre-tax arithmetic above.

Half a per cent a year is not half a per cent

Charges are levied on the balance, so they compound against you exactly as returns compound for you. In the example above, 0.5% a year takes $78,857 out of the pot over 32 years — and that figure understates the damage, because it counts only the money charged, not the growth that money would have gone on to produce.

The comparison worth running is on the calculator itself. Set the charge to 1.0% instead of 0.5% and the pot in today’s money falls by roughly a tenth. That is a difference of several years of contributions, produced by a number that appears in a fund factsheet as a rounding-sized decimal.

US index funds are commonly 0.03% to 0.20%, but plan administration fees ride on top and vary enormously between employers — small plans in particular can carry well over 1% all-in. The disclosure arrives annually under the Department of Labor’s 404(a)(5) rule, and it is usually the least-read document a plan sends. The charge field above exists so that the number can be seen doing its work.

Assumptions and sources

Contribution limits

IRS Notice 2025-67 / IR-2025-111, published 13 November 2025 — §402(g) deferral $24,500, catch-up $8,000, ages 60–63 catch-up $11,250, §415(c) total additions $72,000, IRA $7,500. checked 2026-08-24

Full retirement age

Social Security Administration — 67 for anyone born 1960 or later, earliest claim at 62. checked 2026-08-24

The arithmetic

Monthly annuity-due accumulation, inflation-adjusted, with the sustainable withdrawal solved by bisection rather than assumed at 4%. Verified in tools/test/work.mjs against the closed-form annuity-due.

What this does not know

Your tax bracket now or later, your plan’s vesting schedule, your actual Social Security benefit, the sequence in which returns arrive, and whether markets deliver anything resembling a steady average. All of those change the answer.