How to Read the MICR Line on a Check
The MICR line at the bottom of every check contains your routing number, account number, and check number in a standardized format. Here's how to read it.
The row of numbers at the very bottom of every US check is called the MICR line — short for Magnetic Ink Character Recognition. Printed in magnetic ink using a special font, this line contains three critical pieces of banking information: your routing number, your account number, and the check number. Knowing how to read it correctly prevents the most common mistakes when setting up payments.
What Is MICR?
Magnetic Ink Character Recognition was developed in the 1950s by the American Bankers Association to allow high-speed check sorting machines to read the information at the bottom of checks automatically. The special MICR font — officially called E-13B — uses thick, stylized digits designed to be readable by both humans and magnetic readers. The ink contains iron oxide particles that can be magnetized and detected by sorting machines.
MICR technology allowed banks to process millions of checks per day automatically, replacing the manual sorting that had been required since the paper check era began. Today, even as paper checks decline, the same MICR format is used for digital check images in mobile deposit and Check 21 processing.
The Three Fields on the MICR Line
Reading from left to right, the MICR line contains:
- Routing number (leftmost): Nine digits identifying your bank, surrounded by transit symbols (⑆). This is the field you use for direct deposit, ACH payments, and wire transfers. Look up any routing number with our free tool.
- Account number (middle): Your unique account number at that institution, surrounded by on-us symbols (⑈). Length varies by bank — typically 8 to 17 digits.
- Check number (rightmost): The sequential check number matching the number printed in the upper right corner of the check. Some banks print the check number before the account number — format varies slightly by institution.
The Transit Symbols
The MICR line uses four special characters in addition to the ten digits (0–9):
- Transit symbol (⑆): Marks the beginning and end of the routing number field
- On-us symbol (⑈): Marks the beginning and end of the account number and check number fields
- Amount symbol (⑇): Used to delimit the dollar amount field when added by the processing bank
- Dash symbol (⑉): Used within some fields as a separator
Reading the MICR Line: A Practical Example
A typical MICR line might look like this:
⑆021000021⑆ 123456789⑈ 1001
In this example: 021000021 is the routing number (JPMorgan Chase, New York), 123456789 is the account number, and 1001 is the check number. You can verify any routing number from a MICR line using our lookup tool.
Why This Matters for Mobile Check Deposit
When you take a photo of a check for mobile deposit, your bank's app captures the MICR line digitally and extracts the routing number automatically. This is why check photos need to be clear and well-lit — a blurry or cut-off MICR line can cause the routing number to be misread, resulting in a failed or delayed deposit.
Browse institutions in our bank directory or look up routing numbers by state. Our guides section has more on check-related routing number topics, including how the ABA checksum protects against misread routing numbers.