How does 401k matching work?

When you contribute to the 401(k), your employer will make a matching contribution, capped at a certain percentage of your compensation. For example, if your employer matches all of your contributions for the first 3%, half for the next 2%, and nothing after that, then:

• you contribute 3%, your employer makes 3% matching contribution
  
• you contribute 5%, your employer makes 4% matching contribution
• you contribute 7%, your employer makes 4% capped matching contribution

If your employer matches your contributions dollar-for-dollar capped at 5%, then it'll be a straight match with no further matching contributions after you contribute 5% of compensation.
Your 401(k) plan may be set-up with a vesting schedule, which means the employer match may be allocated to you but only becomes yours ("vests") over a period of years service. Check out the Summary Plan Description (SPD) for details on all this.
​I hope that helps. All the best!