Knowing that your kids are safe, happy and thriving when you’re at work: priceless. Hiring the person who provides that care, though? It’s going to cost you. An experienced nanny’s hourly rate will probably be on par with that of an experienced babysitter in your area. But, while you can hire a sitter for short periods of time and pay her cash, hiring a nanny is a big commitment. You become her employer, which means she’ll count on you for a certain number of hours each week, and you’ll take on certain legal and tax requirements. Make sure you’re ready to take on that financial burden before hiring your own Mary Poppins.

You can expect to pay a nanny an hourly rate that’s equivalent to what you’d pay a babysitter, but that will vary based on your location and the cost of living in your area. For example, a nanny working in a major city or an expensive town or suburb can typically earn $15 to $17 per hour or even more. In a smaller town or in most suburbs, nannies can make anywhere from about $10 to $15 per hour.

All those hours add up. A nanny who earns $16 an hour and works 40 hours a week, 50 weeks a year, will earn $32,000 annually. By comparison, a nanny who earns $13 an hour will make $26,000 per year, assuming she works 40 hours a week and has two weeks off.

If you work with a nanny agency, expect to pay an additional $1,000 or more in application and placement fees.

Your family’s unique needs and the availability of nannies in your area will affect the specific rate you pay. You can pay a lower hourly rate if you hire a live-in nanny because room and board will be part of her compensation, but you still must pay her at least the hourly minimum wage in your state.

Experience matters too. The longer she’s worked as a nanny and the more positive references she has, the more attractive a candidate she is—and that means she can charge more than her less-experienced competitors. All nannies should have basic first-aid training and CPR certification, so those credentials alone shouldn’t affect the wage you pay a nanny.

When you’re trying to pinpoint the salary you’ll offer, consider the scope of the job. If you have several rambunctious kids and want your nanny to do some cooking and cleaning, expect to pay a little more than you’d pay a nanny whose only job is to care for one child.

Ultimately, you may not be able to get a nanny for the price you’re willing to pay unless you take a chance on a less-experienced nanny. In most larger cities, the experienced pros tend to be so high in-demand that they can be choosy about whom they work for. But no matter your prospective nanny’s resume, don’t hire anyone unless you’ve met several times, and she’s met and gelled with your kids. Call all references, run a background check, and start her on a trial basis before you commit to a permanent arrangement.

When you hire a nanny, you become an employer. That means you have to meet certain legal and financial obligations, such as withholding federal income taxes from her paycheck and complying with employment law. Work with a payroll firm to make sure you’re handling her paychecks and taxes correctly.

You also may want to consult with an attorney or at least research your state’s laws and the national Fair Labor Standards Act. Nannies are covered under the act, which means they’re entitled to overtime pay if they work more than 40 hours in a week. Individual states have different laws about domestic employees, so get familiar with yours to make sure you’re treating your nanny both fairly and legally.