How overdrafts happen
An overdraft occurs when you spend more money than you have in your account, and your bank covers the difference. The bank is lending you that money temporarily—usually for a fee. You overdraft when a transaction posts (clears) and your balance would go below zero, but the bank processes it anyway instead of declining it.
This can happen in several ways. A debit card purchase at a store, a check you wrote, an automatic bill payment, or an ATM withdrawal can all trigger an overdraft if your balance is too low. The transaction goes through, your account balance becomes negative, and you now owe the bank both the amount you overspent and an overdraft fee.
Not every transaction causes an overdraft the same way. Debit card purchases often process immediately, while checks and ACH transfers (like automatic bill payments) may take one to three business days to clear. This delay means you might think you have enough money when you actually don't—a common reason people overdraft without realizing it.
Key Takeaways
- An overdraft happens when a transaction posts and your balance goes negative, and your bank covers the shortfall for a fee.
- Debit card purchases, checks, ATH withdrawals, and automatic payments can all cause overdrafts, depending on your account balance when each one clears.
- Checks and ACH transfers take one to three business days to clear, so your available balance may not match your actual balance.
- Most banks charge between $25 and $40 per overdraft, and multiple overdrafts in one day can each trigger a separate fee.
- You can opt out of overdraft coverage for debit card and ATM transactions, which will cause those transactions to be declined instead.
When your bank covers the transaction
Your bank will cover an overdraft only if you have overdraft coverage enabled on your account. This is usually the default setting when you open a checking account, though you can turn it off. When coverage is on and you overdraft, the bank pays the merchant or recipient and charges you an overdraft fee—typically $25 to $40 per transaction, though this varies by bank.
The fee is separate from the amount you overspent. If you overdraft by $5 and your bank charges a $35 fee, you now owe $40 total. If multiple transactions post on the same day and each one pushes you further negative, you may be charged a separate overdraft fee for each one. Some banks cap the number of overdraft fees they'll charge in a single day (often at three or four), but others do not.
Banks typically process transactions in a specific order each day, which can affect how many overdraft fees you incur. Most banks process debit card transactions before checks and ACH transfers, meaning a check that arrived first might clear after a debit card purchase, even though you wrote the check earlier. This ordering can create multiple overdrafts from transactions you thought were spaced out.
What happens if you decline overdraft coverage
If you opt out of overdraft coverage for debit card purchases and ATM withdrawals, those transactions will simply be declined instead of going through. Your card will be rejected at the register, or the ATM will refuse to dispense cash. You won't overdraft, and you won't pay a fee—but you also won't get the money or the item you were trying to buy.
Opting out does not protect you from overdrafts on checks or ACH transfers (automatic bill payments). Banks are required by law to allow you to decline overdraft coverage for debit and ATM transactions, but they can still cover checks and ACH transfers if you have overdraft protection enabled. If a check clears and you don't have the funds, you will overdraft and pay a fee unless you have a linked savings account set up to cover it.
To opt out of overdraft coverage for debit and ATM transactions, contact your bank directly—by phone, in person, or through your online banking portal. The process takes a few minutes, and the change usually takes effect immediately or within one business day. You can turn coverage back on at any time using the same method.
Overdraft protection and linked accounts
Some banks offer overdraft protection, which links your checking account to a savings account or line of credit. If you overdraft, the bank automatically transfers money from the linked account to cover the shortfall. This prevents the overdraft fee and keeps your transaction from being declined.
Overdraft protection is different from overdraft coverage. With protection, money moves from one of your own accounts (or a credit line) to prevent the overdraft from happening at all. With coverage, the bank lends you the money and charges a fee. Protection is usually free or costs a small monthly fee, while coverage always costs an overdraft fee per transaction.
If you have overdraft protection linked to a savings account, the transfer may happen automatically and instantly, or it may take one business day depending on your bank. If the linked account doesn't have enough money to cover the overdraft, the transfer will fail and you'll overdraft anyway. Check your bank's terms to understand how transfers work and whether there are any fees involved.
How overdraft fees add up
A single overdraft fee is usually $25 to $40, but the real cost comes from multiple overdrafts in a short time. If you overdraft three times in one week, you could pay $75 to $120 in fees alone—money that goes to the bank, not toward paying back what you actually owe.
The fees compound the problem. After you overdraft, your balance is now negative by the amount you overspent plus the fee. If you don't deposit money right away, your next transaction might overdraft again, triggering another fee. A $10 overspend can cost $50 or more by the time you've paid two overdraft fees and the original amount.
Some banks offer overdraft fee forgiveness or refunds if you have a good account history or if you bring your account current within a certain number of days. Call your bank and ask whether they will waive or refund fees, especially if this is your first overdraft or if you've been a customer for a long time. Banks have discretion here, and asking can sometimes work.
Paying back an overdraft
To clear an overdraft, you need to deposit enough money to cover both the amount you overspent and the overdraft fee. If your account is negative by $45 (a $10 overspend plus a $35 fee), you must deposit at least $45 to bring your balance back to zero.
You can deposit money by direct deposit, mobile check deposit, ATM deposit, in-person deposit at a branch, or transfer from another account. The deposit should post within one business day, though some methods (like mobile check deposit) may take longer. Once the deposit clears and your balance is positive, you can use your account normally again.
If you don't pay back the overdraft, your bank may eventually close your account and send the debt to a collection agency. Banks typically give you 30 to 60 days to resolve a negative balance before taking this step, but policies vary. A closed account and collection report will damage your credit and make it harder to open a new account elsewhere.
How to avoid overdrafting
The most reliable way to avoid overdrafts is to keep a buffer in your checking account—money you don't spend, so your actual balance is always higher than your available balance. A $100 or $200 buffer catches most accidental overdrafts. This requires discipline, but it's cheaper than paying overdraft fees.
Monitor your balance regularly using your bank's app or website, especially before making large purchases or paying bills. Remember that your available balance may not include checks or ACH transfers that haven't cleared yet. If you're unsure whether a transaction has posted, assume it hasn't and subtract it from your available balance manually.
Set up overdraft protection if your bank offers it, or opt out of overdraft coverage for debit and ATM transactions if you prefer to have purchases declined rather than overdraft. Turn on low-balance alerts if your bank provides them—these send you a text or email when your balance drops below a threshold you set, giving you time to deposit money before you overdraft.
Frequently Asked Questions
Can a bank overdraft my account if I don't have overdraft coverage turned on?
No, not for debit card purchases and ATM withdrawals. If you've opted out of overdraft coverage for those transactions, they will be declined. However, banks can still cover checks and ACH transfers even if you've declined coverage for debit transactions, so you can still overdraft on those.
What's the difference between available balance and account balance?
Your account balance is the total money in your account right now. Your available balance subtracts pending transactions—checks and ACH transfers that haven't cleared yet. If your account balance is $500 but you have a $300 check pending, your available balance is $200. Overdrafts are calculated against your account balance, not your available balance.
If I overdraft multiple times in one day, do I pay multiple fees?
Yes, usually. Each transaction that posts while your balance is negative typically triggers its own overdraft fee. Some banks charge a maximum of three or four overdraft fees per day, but others do not. Check your bank's overdraft policy to see if there's a daily cap.
Can I get an overdraft fee refunded?
Sometimes. Call your bank and ask, especially if this is your first overdraft or if you've been a customer for years. Banks have the discretion to waive or refund fees. They're more likely to help if you bring your account current quickly and if you have a good history with them.
What happens if I don't pay back an overdraft?
Your bank will eventually close your account and may send the debt to a collection agency. This typically happens 30 to 60 days after the overdraft, though timelines vary. A collection report will hurt your credit score and make it difficult to open a new bank account.