Writing $400 on a Check: Complete Instructions for Getting It Right

While digital payments dominate modern banking, knowing how to properly fill out a check—including specific amounts like $400—remains essential. Whether you’re paying a vendor, settling a utility bill, or making any financial transaction, understanding how to write $400 on a check correctly ensures your payment is processed smoothly and protects you from fraud. This comprehensive guide walks you through every step of writing, endorsing, and depositing a check with confidence.

Understanding Your Check’s Key Components

Before you write your first check for $400 or any amount, familiarize yourself with the three critical numbers on every printed check. These numbers appear in consistent locations and serve specific purposes in the banking system.

The routing number is a nine-digit code unique to your bank, used for identifying your financial institution in all transactions. This is the number you’ll need whenever you set up automatic payments or conduct online banking.

Your account number is the second essential identifier—this is your individual checking account, distinct from any other accounts you may hold. It works in conjunction with your routing number to identify your specific account.

The check number is the sequential identifier printed on each physical check. You’ll notice it appears twice on your check: once in the upper right corner and again after your account number at the bottom.

Filling Out Your Check Properly: Focus on the Amount

Writing a check requires attention to detail, especially when recording monetary amounts. Here’s the proper method for completing each field on your check, with particular attention to how you’ll write $400 or any similar amount.

Start with the date in the upper right corner. Write today’s date or whenever you’re actually writing the check. This timestamp helps the recipient track when payment was issued.

Next, identify the recipient. On the line marked “Pay to the Order of,” write the exact name of the person, business, or organization receiving your payment. Verify the spelling of the recipient’s name to avoid complications.

For the numerical amount, write your payment in the box on the right side of the check. If you’re sending $400, write “$400.00” or “$400” close to the left border of this box. This positioning is critical—by leaving no space to the left of your amount, you prevent someone from fraudulently adding digits (for example, changing “$400” to “$5,400”).

The written-out amount is equally important. Below the “Pay to the Order of” line, write out your amount in words. For $400, you would write “Four hundred dollars and 00/100” or simply “Four hundred dollars.” If you were writing a check for $400.50, you’d write “Four hundred dollars and 50/100.” The written version legally takes precedence if any discrepancy exists between the numerical and written amounts, making accuracy essential.

Use the memo line to note the purpose of your payment. Writing your account number, reference number, or brief description here helps you and the recipient track the transaction.

Sign the check on the line in the bottom right corner. Your signature authorizes the payment and validates the check. Without a proper signature, your check is legally invalid.

Real-World Example: Writing a $400 Payment

Let’s apply these principles to a concrete scenario. Imagine your internet service provider sends you an invoice for $400.00 for monthly service, and they require check payment. Here’s exactly how you’d complete that check:

Write the date you’re mailing the check in the upper right corner—for instance, if you’re mailing on February 16, 2026, write “2/16/2026” or “February 16, 2026.”

Enter the recipient’s name. On the “Pay to the Order of” line, write the exact name shown on your invoice. You might write “Internet Service Company” or whatever the official business name is.

Record the numerical amount in the box on the right side: “$400.00”. Position this close to the left edge of the box to prevent alteration.

Write out the amount on the line below “Pay to the Order of”: “Four hundred dollars and 00/100”. This written-out version is your legal protection.

Add a memo if the provider requires it. You might write “Internet bill February 2026” or your account number if they’ve requested it.

Sign your check after verifying all information is correct. This completes your valid check, ready to mail.

Writing the Amount in Words: Why Precise Dollar Amounts Matter

The written-out amount on your check serves a critical function in banking law. When you write “Four hundred dollars” for a $400 check, you’re creating a legal record that protects both parties. If someone attempts to alter your check—say, trying to change the numerical amount from $400 to $4,000—the written words “Four hundred dollars” would take precedence in any dispute.

This is why precision in writing both the numerical and written forms of your amount is non-negotiable. A $400 check isn’t just about transferring funds; it’s a binding financial instrument. Banks are trained to flag inconsistencies between numerical and written amounts, and significant discrepancies may cause your check to be rejected or delayed.

Recording your transactions carefully is equally important. Use a check register, spreadsheet, or banking app to track each check you write—including the check number, date, recipient name, amount ($400 in this example), and transaction description. This record-keeping helps you reconcile your bank statements and catch any errors or fraudulent activity.

Protecting Your Check: Security When Writing Specific Amounts

Regardless of whether you’re writing a $400 check or any other amount, security precautions are essential. Check fraud costs millions annually, and you can protect yourself by following these guidelines:

Always use a pen—never pencil—when writing checks. Pencil can be erased, allowing someone to alter your check after you’ve signed it. Pen creates a permanent, tamper-evident record.

Never sign a blank check or fill one out before adding the payee and amount. An unfinished check in the wrong hands could be completed for any amount by a fraudster.

Avoid writing checks payable to cash. “Cash” checks can be deposited or cashed by anyone, making them vulnerable to theft if lost or intercepted.

Leave no blank space on your check, particularly around the amount field. Write “$400.00” at the left edge, not “$400” floating in the middle. Close any remaining space with a line to prevent insertion of additional digits.

Store unused checks securely in a locked drawer or safe. If you notice missing checks, contact your bank immediately.

These practices significantly reduce your risk of becoming a check fraud victim while ensuring your $400 payment—or any amount—reaches its intended recipient intact.

Endorsing Your Check: Multiple Methods Explained

When you receive a check for $400 or another amount, you must endorse it before depositing or cashing it. An endorsement is your signature on the back of the check, confirming you’re the authorized recipient.

For blank endorsements, simply sign your name on the back where indicated. This is the most common method but also the least secure—anyone holding the check could potentially cash it. You’ll tell the bank teller whether you want it deposited or cashed.

To secure your endorsement, write “For Deposit Only to Account Number [your account number]” followed by your signature. This restricts how the check can be used, adding a security layer. Wait until right before depositing to add your signature for maximum protection.

For third-party endorsements, you can transfer a check made out to you to another person by writing “Pay to the order of [recipient name]” and signing below. Not all banks accept this method, so verify first.

Mobile deposit endorsements may require writing “For Mobile Deposit Only to [Bank Name]” before signing, depending on your bank’s requirements.

Business checks require an authorized company representative’s signature, including the business name, the signatory’s title, and possibly “For Deposit Only” notation.

Multiple payee checks require endorsement from all payees if the check reads “Jane and John Doe.” If written as “Jane or John Doe,” either party can endorse alone.

Depositing Your Check: Available Methods

Once your check for $400 is properly filled out and endorsed, you have several deposit options:

In-person deposits let you visit your bank branch, hand your endorsed check to a teller, and specify whether you want it deposited or cashed. Bring a valid ID.

ATM deposits are available at many banks and credit unions. Endorse your check, insert it into the ATM, and follow the on-screen prompts. Some ATMs require an envelope for deposits.

Mobile check deposits through your bank’s app have become increasingly popular. Take photos of both the front and back of your endorsed check, select the deposit account and amount, and upload the images. Keep the physical check until funds clear, then destroy it.

Ordering New Checks

Once you’ve written multiple checks, you’ll eventually need to order more. Many banks provide complimentary checks when you open an account, but if not, you can order through several channels:

Order through your bank’s website or app by logging into your account and navigating to the customer service section. This is usually the most convenient option.

Visit your local bank branch or call customer service to order checks over the phone.

Use third-party check providers that partner with your bank or operate independently. You’ll need your routing number, account number, and starting check number.

Check costs vary based on the style and where you order them. Basic personal checks are generally the most affordable option. Have an existing check nearby when ordering so you have all necessary information at hand.

Mastering Check Writing for Financial Control

Writing a $400 check—or any check—properly is a fundamental banking skill that remains relevant despite digital payment innovations. By understanding check components, correctly filling out amounts both numerically and in words, following security protocols, and properly endorsing and depositing checks, you maintain control over your financial transactions and protect yourself from fraud. Whether you’re settling bills, making business payments, or transferring funds, these skills ensure your checks are processed accurately every time.