Where is the routing number on a check?

The routing number is the first 9-digit number in the MICR line at the bottom-left of the check. It identifies your bank. It is always exactly 9 digits long.

Where is the account number on a check?

The account number is the second set of numbers in the MICR line at the bottom of the check, usually 8–12 digits. It comes after the routing number and before the check number.

What is the MICR line on a check?

The MICR (Magnetic Ink Character Recognition) line is the row of numbers printed in special magnetic ink at the very bottom of a check. It contains your routing number, account number, and check number — used by banks for automated processing.

What does the memo line on a check do?

The memo line (lower left) is optional and has no effect on whether a check clears. Use it to note the purpose of the payment — invoice number, rent month, account number with the payee. It helps both parties reference the transaction later.

What is the check number used for?

The check number (upper right corner and in the MICR line) helps you track checks in your register and identify which check cleared. Banks use it to match records. It does not affect processing or clearing.

Parts of a Check Explained 2026 — Every Field and Number Decoded

A standard personal check has 9 key parts. The three most important are the routing number (identifies your bank), the account number (identifies your account), and the MICR line (the machine-readable strip at the bottom that banks use to process the check automatically). Understanding each field helps you fill out checks correctly and avoid costly errors.

Check Anatomy: Labeled Diagram

┌─────────────────────────────────────────────────────────┐
│  YOUR NAME                                    [1] 1042  │  ← Check Number
│  123 Main Street                                        │
│  Anytown, USA 12345                                     │
│                                                         │
│  PAY TO THE ORDER OF _____________________  [2] $______ │  ← Payee / Amount
│                                                         │
│  _____________________________________________ DOLLARS  │
│  [3] Amount in words                                    │
│                                                         │
│  [4] FIRST NATIONAL BANK        [5] MEMO: ___________  │  ← Bank / Memo
│      Anytown Branch                                     │
│                              [6] SIGNATURE: __________ │  ← Your Signature
│  ⑆123456789⑆  ⑈987654321⑈  1042                       │
│   [7] Routing    [8] Account   [9] Check #              │  ← MICR Line
└─────────────────────────────────────────────────────────┘

The 9 Parts of a Check, Explained

1. Check Number (Upper Right)

A sequential number printed in the upper right corner and again in the MICR line at the bottom. Check numbers start at 101 (or 001) and increment with each check.

Purpose: Helps you track checks in your register. When a check clears, your bank statement will show the check number so you can match it.

Important: The check number does not affect processing. Banks don’t care what number it is — they care about the routing and account numbers.

2. Date (Upper Right)

The date you write the check. Checks are generally valid for 6 months (180 days) from this date. After that, they become “stale-dated” and banks may refuse to honor them.

Post-dating: Writing a future date on a check does not legally prevent a bank from cashing it early — though many banks will attempt to honor the date. If you need to delay payment, stopping payment is more reliable.

3. Payee Line — “Pay to the Order Of”

The name of the person or company you’re paying. Write it clearly and completely. Abbreviations that don’t match the payee’s legal name can cause problems when they try to deposit the check.

Tips:

Use the legal name of a business, not a nickname
If paying cash (making the check cashable by anyone), write “Cash” — but treat this like handing over cash; anyone who finds it can cash it
Never leave this line blank

4. Numeric Amount Box (Right Side)

Write the dollar amount as a number in the small box after the “$” sign. Be as specific as possible — include cents:

Correct: 1,247.50
Avoid: 1247.5 or $1,247.50 (the $ is already printed)

Start writing at the far left of the box to prevent someone from adding digits before your number.

5. Written Amount Line

Spell out the dollar amount in words. The cents are written as a fraction over 100:

Example: One thousand two hundred forty-seven and 50/100 DOLLARS

Rule: If the numeric amount and written amount disagree, banks typically use the written amount. Fill in both carefully.

Draw a line after the written amount to fill any blank space — this prevents someone from adding words.

6. Memo Line (Lower Left)

Optional. Write a note about the payment’s purpose:

Invoice number or reference
Month and year for rent payments
Your account number with the payee
A description of goods or services

The memo line has no effect on whether the check clears or how it’s processed. It’s purely for recordkeeping.

7. Your Signature (Lower Right)

Your legal signature — must match the signature on file with your bank. Without a valid signature, a check is invalid and should not be paid.

Never sign a blank check. If you fill in everything except the amount and sign it, you’ve given the holder a blank check they can fill in for any amount.

8. Bank Name and Address

Your bank’s name and usually the branch address appears in the lower left area (often with a logo). This tells the payee and processing system where the check is drawn.

9. The MICR Line (Bottom Strip)

The MICR (Magnetic Ink Character Recognition) line is the row of numbers and symbols printed in special magnetic ink at the very bottom of every check. It contains:

⑆ ROUTING NUMBER ⑆  ACCOUNT NUMBER ⑈  CHECK NUMBER

Component	Position	Digits	What It Identifies
Routing number	First	9	Your bank (ABA routing)
Account number	Middle	8–12	Your specific account
Check number	Last	4	This specific check

Routing number: Always exactly 9 digits. The same for all customers at your bank (for a specific account type). Used to direct the payment to the right financial institution. See our full guide to finding your account number on a check for help identifying each number.

Account number: Unique to your account. Varies in length (typically 8–12 digits). Never share this with people you don’t trust — combined with your routing number, it can be used to set up electronic payments.

Check number: Repeats the check number shown in the upper right corner.

How Banks Process Your Check

When the payee deposits your check:

The bank scans the MICR line to extract routing, account, and check numbers
The check is transmitted electronically to your bank (most checks never physically travel anymore)
Your bank verifies the signature and that funds are available
The funds are withdrawn from your account, typically within 1–2 business days

For the full timeline of how long checks take to clear, see how long a check takes to clear.

Common Mistakes to Avoid

Mistake	Consequence
Leaving payee line blank	Anyone can write their name and cash it
Writing amount starting mid-box	Someone can add digits before the number
Numeric and written amounts don’t match	Bank uses written amount; could cause disputes
Signing a blank check	Holder can fill in any amount
Forgetting to date the check	Some banks will refuse it
Misspelling the payee’s name	May cause deposit problems for the recipient

Written by WealthVieu

WealthVieu researches and writes data-driven personal finance guides using primary sources including the IRS, Bureau of Labor Statistics, Federal Reserve, and Census Bureau.

The content on Wealthvieu is for informational purposes only and should not be considered financial, tax, or investment advice. Consult a qualified professional before making financial decisions. Full disclaimer · Editorial policy