How a 401(k) Employer Match Works (Free Money)

Common match formulas

The most common US formula is a full match on the first 3% of pay plus a half match on the next 2% — often written "100% up to 3%, then 50% up to 5%". Contribute 5% and the employer adds an effective 4%. Some firms simply match dollar-for-dollar up to a cap like 4% or 6%.

Whatever the formula, the pattern is the same: the employer only pays when you do. Contributing below the match threshold leaves money on the table; the calculator shows exactly how much you'd forfeit at each contribution level.

Why it's called "free money"

A dollar-for-dollar match is an instant 100% return — no market beats that reliably. Even a 50% match is a guaranteed 50% gain the moment it lands, before any investment growth. That's why financial advisers rank capturing the full match above almost every other savings goal, including paying down moderate-rate debt.

The match also compounds. Money added early has decades to grow, so a few thousand of employer contributions in your twenties can become a large share of your final balance. Skipping the match doesn't just cost today's dollars — it costs all their future growth.

Vesting: when the match is really yours

Your own contributions are always yours, but the employer match may vest over time. Some plans vest immediately; others use a schedule where you keep, say, 20% more each year and are fully vested after five. Leave before you're vested and you forfeit the unvested portion.

Always check your plan's vesting schedule before changing jobs, especially if you're close to a cliff. Timing a departure a few months later can mean keeping thousands you'd otherwise leave behind.

Frequently asked questions

What does a 401(k) match actually mean?

Your employer adds money to your retirement account based on your own contributions — for example matching the first 3–5% of pay. It's compensation you only get if you contribute.

How much should I contribute to get the full match?

At least up to the match threshold. If your plan matches up to 5% of pay, contribute 5%. The calculator shows the exact percentage that captures every available employer dollar.

What is vesting?

Vesting is when the employer's contributions become permanently yours. Your own money is always yours, but the match may take a few years to fully vest, and unvested amounts are lost if you leave early.

Should I still contribute if I have debt?

Usually contribute at least enough for the full match first — a 50–100% match beats the interest on most debts. Then tackle high-rate debt before adding more beyond the match.