Your $400 becomes the account's opening deposit

When you open a savings account and put in $400, that money is now held by the bank in an account registered to you. The bank records this as your opening deposit — the first money that goes in. That $400 sits in the account and begins earning interest from the day it arrives, even if you never add another dollar.

The bank does not take a cut of that $400 for opening the account. Some banks charge a monthly fee to maintain the account, but that fee comes out of your balance separately — it is not deducted from your opening deposit. Other banks charge no monthly fee at all, which means your $400 stays intact and only grows.

Your bank will send you a statement — either by mail or email, depending on what you chose — showing that $400 as your opening balance. This statement is your proof of the deposit and your record of what the account holds.

Key Takeaways

  • Your $400 opening deposit begins earning interest when ready, even before you make another deposit.
  • The bank does not deduct a fee from your opening deposit; monthly maintenance fees, if they exist, are charged separately.
  • You will receive a statement showing your $400 as the opening balance and listing any interest earned or fees charged.
  • The interest rate your $400 earns depends on the bank and the type of savings account, and rates change over time.
  • You can withdraw your $400 at any time, though some accounts limit how many withdrawals you can make per month without a fee.

How interest is calculated on your opening deposit

The bank pays you interest on your $400 based on the account's annual percentage yield, or APY. This is the percentage of your balance the bank will pay you each year. If your account has a 4.5% APY, the bank will pay you roughly $18 per year on a $400 balance (though the exact amount depends on how the bank calculates daily interest).

Interest is usually paid monthly or quarterly — meaning the bank adds a small amount to your account every month or every three months. You do not have to do anything to receive it; the bank calculates it and deposits it automatically. Over time, you also earn interest on the interest you have already earned, which is called compounding.

The APY varies widely between banks. An online bank might offer 4% or higher, while a traditional brick-and-mortar bank might offer less than 1%. The higher the APY, the more your $400 grows. This is why comparing rates before you open an account matters.

What happens if you do not add more money

Your $400 can stay in the account indefinitely without any additional deposits. The bank does not require you to add money on a schedule or reach a minimum balance beyond what you already have. Your $400 will continue to earn interest each month or quarter, and your balance will slowly grow.

However, if the bank charges a monthly maintenance fee and your balance drops below a certain threshold — often $500 or $1,000 — the fee may kick in. Once a fee is charged, it comes out of your balance. If you have only $400 and the fee is $10 per month, your balance shrinks to $390, then $380, and so on. This is why it is important to check whether your specific account has a minimum balance requirement or a fee structure.

Many banks waive monthly fees if you set up direct deposit (having your paycheck sent straight to the account) or if you maintain a certain balance. Since you are starting with $400, reading the account agreement before you open it tells you whether fees will explore to you.

Withdrawal limits and how they affect your $400

Some savings accounts limit how many times you can withdraw money per month without paying a fee. This limit is often five or six withdrawals per month, though it varies by bank. Your opening $400 is subject to these same limits — if you withdraw it all at once, that counts as one withdrawal.

If you exceed the withdrawal limit, the bank typically charges a fee for each extra withdrawal, usually $10 to $35. This fee comes out of your account balance. So if you withdraw your $400 and then make several more withdrawals in the same month, you could owe fees that exceed what you withdrew.

Some banks have removed withdrawal limits entirely, so check your account's rules. If you think you will need to access your money frequently, a bank without withdrawal limits or with higher limits is a better fit than one with strict restrictions.

How your bank records and protects your $400

When you deposit $400, the bank records it in a ledger tied to your account number. This ledger is the official record of what you own. Your bank statement shows the same information — your opening deposit, any interest earned, any fees charged, and your current balance.

Your $400 is protected by FDIC insurance if your bank is FDIC-insured, which most banks in the United States are. FDIC insurance means that if the bank fails, the federal government will reimburse you up to $250,000 per account. Since your $400 is well below that limit, it is fully protected.

You can check whether your bank is FDIC-insured by visiting the FDIC's website or asking the bank directly. The bank is required to display the FDIC logo and insurance information in the branch and online.

What your opening deposit means for future account activity

Your $400 is your baseline. Every deposit you make after that increases your balance. Every withdrawal decreases it. Every fee charged reduces it. Every interest payment increases it. Your statement will always show your current balance — what you have right now — which is calculated from your opening deposit plus or minus everything that has happened since.

If you deposit another $200 next month, your balance becomes $600 (plus any interest earned and minus any fees). If you withdraw $100, it becomes $500. The opening deposit is straightforward the starting point, not a separate thing that sits apart from the rest of your account.

Understanding this matters because it helps you track your money and predict what your balance will be. If you know your opening deposit, the interest rate, and the fees, you can estimate what your account will hold in three months or six months.

Frequently Asked Questions

Does the bank take any money from my $400 when I open the account?

No. Your full $400 becomes your opening balance. The bank does not deduct an opening fee from the deposit itself. If the account has a monthly maintenance fee, that is charged separately and comes out of your balance each month, but it is not taken from your opening deposit upfront.

When do I start earning interest on my $400?

Interest begins accruing on the day your deposit is processed and posted to the account. Most banks calculate interest daily and pay it monthly or quarterly. You do not have to wait for your first statement to see interest being earned — it is working from day one.

What if I need to withdraw my $400 before the month ends?

You can withdraw your $400 at any time. If your account allows five or six withdrawals per month without a fee, one withdrawal counts toward that limit. If you exceed the limit, a fee applies. Check your account rules to know whether a withdrawal fee will be charged.

Can my $400 balance go negative?

A savings account cannot go negative. If you try to withdraw more than you have, the bank will decline the transaction. You can only withdraw money that is actually in the account. This is different from a checking account, which may allow overdrafts.

Will my $400 ever disappear if I do not use the account?

No. Savings accounts do not expire or close because of inactivity, though some banks may close an account after several years with no deposits or withdrawals. Your $400 will remain in the account and continue to earn interest as long as the account is open. Check your account agreement for any inactivity policies.