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401(k) Basics: What It Is and Why Your Paycheck Cares

Retirement · 6 min read

In one sentence

A 401(k) is a retirement savings account from your employer that quietly moves part of each paycheck into investments for your future self — before you get a chance to spend it.

What it means for your paycheck

When you sign up, you pick a percentage of your salary — say 5%. Every payday, that 5% leaves your paycheck and goes into your 401(k) instead of your bank account.

Two things make this powerful:

  1. It happens automatically. You don't have to remember to save. The money is gone before you see it, so you just... live on the rest. Most people adjust within a month or two and never miss it.
  2. Your employer may add free money. Many companies "match" your contributions. A common formula is "100% match up to 4% of your salary" — meaning if you put in 4%, they put in another 4%. That's an instant doubling of your money. If you contribute less than the match limit, you're turning down part of your pay.

The money in your 401(k) is invested (usually in funds you pick from a short list), so it has a chance to grow over the decades until retirement.

3 things you can do this week

  1. Check whether you're enrolled. Log in to your company's benefits portal or ask HR: "Am I contributing to the 401(k), and at what percentage?" Many people assume they're in and aren't.
  2. Contribute at least enough to get the full employer match. Find your company's match formula (it's in your benefits paperwork — something like "50% up to 6%"). Then make sure your contribution percentage is at least that "up to" number. Anything less is leaving free money on the table.
  3. Bump it 1% once a year. You won't feel 1%, but over 30 years it can mean tens of thousands of dollars. Set a calendar reminder for your next raise.

Try it: the 401(k) match calculator

Want to see exactly how much free money your match is worth — and how much you'd leave behind by contributing too little? Try the interactive calculator:

Open the 401(k) Match Calculator →

This is educational content, not financial advice. Rules and limits change — always check your plan documents or ask your HR team for your specific details.