When you write a check, send it in the mail and wait for a person or company to deposit it, there’s a certain amount of time involved in the money being actually deducted from your checking account. Similarly, if you take a check from someone and deposit it in your account, you bank may impose certain rules about when that money becomes available to you, particularly if the check is large, or comes from a private person or foreign entity. This time, either waiting for money to be deducted or added to your account is called an availability float.

During the time of an availability float, where you’re waiting for someone else to deposit a check you wrote, the money in your bank is still at your disposal. However, it’s a very good idea not to use it, and to record it in your check register to make certain that you don’t bounce a check. You can’t always determine how long an availability float on your check will last. A company could quickly turn it around and deposit it, or not receive or deposit it for a week or more. You should not use the availability float funds because they’ve already been allocated.

Similarly, most banks have policies about availability floats on money you deposit in the form of checks. Some banks, particularly when you have an extended history with the bank will give you instant access to your money, and no availability float time is assessed. In other cases, checks from private parties, unless they initiate from the same bank you use, may mean money is not immediately available to you. Banks may impose a waiting time of one or more days, usually not exceeding a week, before funds become available. Alternately you may only be able to access a portion of the funds, until the check has cleared. Here, you really need to be cautious regarding spending money that has not been credited to your account so you don’t bounce checks.

Online and ATM banking has significantly changed availability float times. If you use an ATM card, funds are usually immediately deducted from you bank account. There are certain systems in place that treat checks in exactly the same manner. If you write a check to a store, the funds might be deducted right away, instead of having any availability float time.

On the other hand, when you mail a check, you can guarantee at least one day of float, since even if the check goes to someplace in the same town, it has to be processed and usually can’t arrive until the next day. If you know a direct deposit is going to be in your account on the following day, you can safely assume you’ve got enough availability float to mail a check the day before, even if the funds in your account are not presently there. You should still observe caution when employing this method; all manner of accidents could cause even your direct deposit paycheck to be delayed.