401(k) calculator, with match and IRS limits.

A 401(k) calculator estimates what your retirement plan could be worth when you stop working. You give it your age, your pay, how much you put in and how your employer matches it, and it adds up the money going in each year and the growth on it. This one also holds your contribution to the IRS limit for your age in every year, works out how much of the employer match you are using, and shows what one more point of pay adds. The return is a number you choose. The page suggests none and promises nothing, because real returns go up and down and can be negative. It is maths on your numbers, not financial or tax advice.

How to use the 401(k) calculator

1. Type your Age now and the age you want to Retire at, then your Yearly pay, before tax and the Pay rise each year (%).
2. Type what is Already in your 401(k).
3. Under You put in, type a share of pay, or switch As to A year to type dollars.
4. Under Employer match, type the match rate and the share of your pay it applies to. For a plan that matches 50% of what you put in, up to 6% of pay, type 50 and 6. Your plan’s summary says how yours works.
5. Type the Return a year (%) you want to test. Open Second match tier, fee, inflation and income for the rest.
6. Read the cards, the notes under them, the chart and the year by year table. Copy result copies a line of text and Copy link to these numbers reopens the page with the same inputs.

IRS limits the page uses

Each year the IRS sets how much you can put in. These are the 2026 amounts, read from the IRS pages 401(k) limit increases to $24,500 for 2026 and 401(k) and profit-sharing plan contribution limits on 24 Oct 2026.

The IRS pages read list 2026 amounts only. Later years are not stated there, so the page holds the 2026 amounts for every year unless you type a yearly rise under IRS limits rise each year by (%). Plans can set lower limits of their own, and a plan may not offer the higher catch-up. Check your plan.

A worked example

Take age 30, retiring at 65, with 80,000 of pay rising 3% a year and 25,000 already saved. You put in 10% of pay. Your employer matches 50% of it, up to 6% of pay, so the employer adds 3% of pay. The return is a steady 6% less a 0.5% fee, a net 5.5%. In the first year you put in 8,000 and the employer adds 2,400. After 35 years you will have put in 483,696.65 and the employer 145,109.00. The balance at 65 is 1,740,455.25. With 2.5% inflation that is worth 733,377.49 as today’s money, and a 4% a year income from it would be 69,618.21, a rate you choose and not a promise.

Without the match the same plan ends at 1,376,391.49, so the match is worth 364,063.76 to you. One more point of pay, 11% instead of 10%, ends at 1,861,809.84, which is 121,354.59 more. Now try putting in only 3%. Your employer still matches 50% of it, but only 1.5% of pay, and the page tells you how much match you are leaving unused.

When the limit bites

Take age 45, retiring at 65, with 300,000 of pay rising 3%, 100,000 saved, 15% put in, and a match of 100% on the first 4% of pay. Fifteen percent of 300,000 is 45,000, which is over the 2026 limit, so the page puts in 24,500 in the first year, and the employer adds 12,000. From age 50 the limit becomes 32,500, and from 60 to 63 it is 35,750. Over the 20 years you put in 623,000 and the employer adds 279,149.55. Because pay passes 360,000 in the seventh year, the match is held at 4% of 360,000, which is 14,400. The plan hits a limit in every year, and the table highlights those rows.

What the page leaves out

• Tax. Traditional contributions are made before tax and taxed when you take the money out, and Roth contributions are the other way round. The page treats all the money the same and takes no tax off.
• Vesting. Some employers keep their match if you leave early. The page assumes you keep all of it.
• Steady returns. Real returns are not steady. A bad year near retirement matters more than the average suggests.
• Social Security, other accounts and what you spend. Use the page for one account, not a whole plan.

To see growth for any account with a fee and a goal, try the investment calculator. For the effect of prices on the result, there is the inflation calculator, and the compound interest calculator shows plain compounding.