An employer match is free money your employer contributes to your retirement account based on how much you contribute. It's one of the most valuable employee benefits available and one of the easiest ways to accelerate your retirement savings.

Common match formulas include dollar-for-dollar up to 3% of your salary, or 50 cents per dollar up to 6% of your salary. For example, if you earn $60,000 and your employer matches 50% up to 6%, you'd need to contribute $3,600 (6%) to get the full $1,800 employer match. That's an immediate 50% return on your investment—far better than any other investment you'll find. The key: contribute at least enough to get the full match. Leaving employer match money on the table is literally turning down part of your compensation. Some employers have a vesting schedule, meaning you need to stay with the company for a certain period before the match money is fully yours, but your own contributions are always 100% yours.