If you’ve ever misplaced or lost a debit or credit card, you know the panicky feeling: Is someone going to use it to drain my account or run up a bunch of unauthorized charges? Now what can I do?

More and more, the answer is simple - turn your card off until you either find it or cancel it. Then turn it back on once all is well.

While this feature can go by a variety of names, the bottom line is that you can take preventive action to block others from using your card.

To check whether or not your cards have the helpful lock/unlock feature, you can sign in to your account via your card issuer’s mobile app or from their website and then look under the Account Services category. If you can’t find that option, call the issuer’s customer service phone number and ask.

When you lock your card, new charges and cash withdrawals will be denied until you turn it back on, but any automatic payments you set up for things like bills will continue to be allowed. How fast does it work? Instantly, whether your locking or unlocking the card.

The on/off feature can be used for more than just a missing card. If you have a card that you rarely use or if you want to block another authorized user from using it, just lock the card until you need it or want it to be cleared for use. The main benefit is that you’re in control of blocking or allowing any new spending.

Experts do recommend that you notify your card issuer of a missing card if you can’t find it right away. You might need to be issued a new card if it truly is gone.

The lock/unlock feature can be used in conjunction with other powerful banking tools such as transaction and balance monitoring, or text and email alerts that can warn you of possibly suspicious purchases or balances falling below a certain threshold. Some cards even come with features that set spending limits, allow spending only within certain geographic areas, and limit when you can make withdrawals.

So, while it’s always wise to keep track of your payment cards, it’s good to know you have the power to turn spending off when there are concerns about the card’s whereabouts and then to turn to card back on when you find it.

The on/off feature is just another tool to help keep your accounts safe from theft and fraud.