401K Calculator

Estimates what a 401k grows to by the age you retire, with your employer's match counted in.

The 401K calculator is built around a US retirement account, so it only appears for accounts in the United States.

Inputs

You

Age now and Retire at: the number of years the money has to grow. Your retirement age must be greater than your current age.

Current 401k Balance: what's in the account today.

Pay

Annual Salary: before tax.

Raise: the yearly percentage increase to your salary. Contributions rise with it.

You put in: the percentage of salary you contribute.

Employer and growth

Rate: how much of your contribution your employer adds.

Limit: the share of salary the match stops at. A 50% match up to 6% is common. It means your employer adds half of what you put in, on the first 6% of salary.

Expected Annual Return: the yearly growth rate on the whole balance. Seven percent is a common long-run assumption.

What you get

Estimated balance at your retirement age. The caption restates it in today's money at an assumed inflation rate, which it names. That's the number to think with.

Beneath it are the Years to retirement, and what You and your Employer put in during the first year. The first year is the one part of a long projection you can check against a payslip.

The breakdown splits the balance into what was Paid in over those years and the Growth on top.

If your contribution rate would put more in than the annual 401k limit allows in any year, the projection stops at the limit and a note says so.

A last line spells out the assumptions: the return, the raise, and the first-year contribution and match.

How to use it

Check you're getting the full match. If you contribute less than the match limit, you're leaving part of your pay on the table. Run it at your current rate and at the limit to see what the difference grows to.

Try small increases. A 1–2% higher contribution, started early, often makes a surprisingly large difference by retirement.

Be conservative with the return. Markets don't deliver a steady rate. Run it at a lower return too, and plan against that figure.

Note

This calculator doesn't have an Add To Budget button. Contributions come out of your paycheck before it reaches you. Run the Paycheck Calculator with your retirement percentage to see the effect on take-home pay, and budget from that figure.