401(k) Calculator

How it works

Starting from your current balance, the calculator steps forward one year at a time until your retirement age. Each year it adds your contribution and your employer's match, applies the assumed investment return to the balance, and then increases your salary by the growth rate for the following year.

Your contribution is your salary multiplied by your contribution percentage. The employer contribution is your salary multiplied by the smaller of the match percentage and the match limit.

All figures are in nominal dollars. Over 25 years, inflation will substantially reduce what the projected balance can buy.

Formula

employee = salary × contribution rate
employer = salary × min(match rate, match limit)
growth   = (starting balance + employee + employer) × return
ending   = starting balance + employee + employer + growth
next year's salary = salary × (1 + salary growth)

Example

Someone aged 40 with $100,000 saved, earning $100,000, contributing 10% with a 4% employer match, assuming a 7% return and 3% raises, would have about $1,791,197 at 65.

They would have contributed $364,593 themselves, their employer $145,837, and investment growth would account for the remaining $1,180,767.

Assumptions and limitations

• The investment return is an assumption you entered, not an expectation. Real returns vary every year and can be negative.
• Contributions are treated as made at the start of each year and earn a full year's return, which slightly overstates growth compared with monthly contributions.
• Employer matching is simplified. Real plans often use tiered formulas such as "100% of the first 3%, then 50% of the next 2%". The match limit here is a simple cap.
• IRS contribution limits, catch-up contributions and the difference between Roth and traditional accounts are not modelled.
• No inflation adjustment is applied.
• This is a planning projection, not a prediction. It is for informational and educational purposes and is not financial, tax or investment advice.

Frequently asked questions