Retirement Savings Calculator

What this tool is used for

• Projecting a balance at retirement from current savings and contributions.
• Seeing what a contribution increase does over a long horizon.
• Comparing two return assumptions on the same plan.
• Understanding the effect of starting five years earlier.
• Producing a figure to check against a provider's projection.

Frequently Asked Questions

What is the 4% rule?

The Trinity Study finding that withdrawing 4% of the initial balance, inflation-adjusted, survived every historical 30-year period tested. It implies a target of 25× annual spending. Later work suggests 3.5% is safer for retirements longer than 30 years.

How much should I be saving?

Common guidance is 15% of gross income including any employer match, starting in your twenties. Starting at 35 rather than 25 typically requires roughly double the rate to reach the same balance, because the lost years are the most valuable ones.

What return should I assume?

Historic equity returns run near 10% nominal, about 7% after inflation, but with severe variability — projections using a flat rate hide sequence-of-returns risk, where poor returns early in retirement do far more damage than the same returns later.

Why does the employer match matter so much?

It is an immediate 50-100% return on the matched portion, which no investment reliably provides. Contributing less than the full match is the one unambiguous mistake in retirement planning.

What is sequence-of-returns risk?

Two retirees with identical average returns can have very different outcomes depending on the ORDER those returns arrive. A crash in the first few years, while you are withdrawing, permanently shrinks the base that must recover — which averages alone never reveal.

How do taxes change the picture?

Substantially, and in opposite directions. A traditional account defers tax to withdrawal, so the balance overstates what you can spend; a Roth is already taxed, so it does not. Comparing the two by balance alone favours the traditional one incorrectly.

What does the projection assume about contributions over time?

That they continue at the rate you entered. Real contributions usually rise with income, which the model does not capture, and stop entirely during career breaks, which it also does not. Re-run it whenever your actual rate changes materially.

Why is a single projected number misleading?

Because it is one path through a range of outcomes. The same assumptions with real market variability produce a wide spread of end balances, so treat the figure as a midpoint to plan around rather than a target you will hit.

Common errors and gotchas

• Treating a projection as a forecast, when returns vary and the figure is illustrative.
• Using one average return, which ignores sequence-of-returns risk entirely.
• Omitting fees and inflation, either of which changes the real answer substantially.
• Forgetting the balance is usually pre-tax, so the spendable amount is lower.
• Assuming contributions continue uninterrupted for the whole period.