401(k) Calculator

How to use the 401(k) calculator

1. Enter your ages. Type your current age and the age you plan to retire.
2. Add your savings and pay. Enter your current 401(k) balance and your annual salary before taxes.
3. Set your contribution. Choose the percentage of your salary you put in each year.
4. Add the employer match. Enter the match rate and the limit from your plan. For a "50% match up to 6%", use 50 and 6. Use 0 if there is no match.
5. Review the assumptions. Open Advanced options to change your yearly raise, the expected return and inflation.
6. Read the results. You will see the balance at retirement in future and today's dollars, the split between your money, your employer's money and growth, what the match adds, and a table of your balance every five years.

Try changing your contribution by one or two percentage points to see how much difference it makes over decades. The numbers are projections based on steady returns, and real markets rise and fall.

How the 401(k) calculator works

The calculator grows your balance month by month. Each year it works out your contribution and your employer's match from your salary, adds them to the account in twelve monthly amounts, and applies your expected return. Your salary then rises by your yearly increase before the next year starts.

Your contribution = Salary × Contribution %

Employer match = Salary × the smaller of (Your contribution %, Match limit %) × Match rate

Balance after a month = Balance × (1 + monthly return) + (Your contribution + Match) ÷ 12

The monthly return is the yearly return converted to a monthly rate, so a 7% annual return compounds to exactly 7% over twelve months.

Worked example

You are 30, plan to retire at 65, have $25,000 saved and earn $75,000 with 3% yearly raises. You contribute 6%, your employer matches 50% of your contribution up to 6% of pay, and your investments return 7% a year.

1. Your first-year contribution is $75,000 × 6% = $4,500.
2. The employer match is $75,000 × 6% × 50% = $2,250.
3. After 35 years the balance is about $1,635,800.
4. You contributed about $272,100, your employer added about $136,000, and growth supplied roughly $1,202,700.
5. With 2.5% inflation, that balance buys what $689,300 buys today.
6. Without the match the balance would be about $1,179,500, so the match is worth roughly $456,300.

How an employer match works

A match is free money, but it usually comes with limits. A common formula is "50% of your contributions up to 6% of your salary". On a $75,000 salary the most you can receive is 3% of pay, or $2,250 a year, and you get it only by contributing at least 6% yourself. Contributing less leaves part of the match unclaimed.

Contribution limits

For 2026 the IRS limit on employee contributions to a 401(k) is $24,500. Workers aged 50 and over can add a $8,000 catch-up contribution, and the combined limit for employee and employer money is $72,000. These limits change most years, so check IRS.gov for the current figures. The calculator shows a warning if your contributions go above the limit, but it does not cap them.

The 4% rule

A common planning guide says you can withdraw about 4% of your balance in the first year of retirement, then adjust for inflation, and expect the money to last about 30 years. The calculator shows 4% of your projected balance as a rough guide to yearly income. It is a rule of thumb, not a promise.