MICR check printing

The MICR line is the row of E-13B characters along the bottom of a check: routing number, account number and check number. Banks sort and post checks by reading it, so it must sit in the right place, in the right font, and print cleanly. MICR toner makes it magnetically readable.

Facts checked October 31, 2026 against the Federal Reserve Banks' Operating Circular 3 (effective November 15, 2021) and the ANSI X9 standards list.

What the bank rules say

• The Federal Reserve Banks generally handle a paper item as a cash item only if its MICR line follows the ANSI placement standard and carries the paying bank's routing number and the amount (Operating Circular 3, §3.1(f)). The amount is encoded by the bank where the check is deposited, so you leave that field blank.
• The paying bank's routing number should also appear in fractional form in the upper right corner (§3.1(g)).
• Check size: 2¾ to 3⅔ inches high and 6 to 8¾ inches long (§3.1(g)). A standard business check is 8.5 x 3.5 in.
• The standards are ANSI X9.100-160-1 (MICR placement) and ANSI X9.100-20 (E-13B print specification).

The MICR line, field by field

Positions are counted from the right edge in 1/8 inch steps. Position 1 starts 5/16 inch from the right edge.

The bottom 5/8 inch of the check is the clear band: nothing but the MICR line may print there, and the characters sit on a baseline 3/16 inch above the bottom edge. Signatures, memo lines and logos must stay above it.

Do you need MICR toner?

The Reserve Banks strongly encourage electronic (image) check processing, and many checks are now read from images rather than magnetically. Even so, out-of-spec MICR printing causes read errors, and some banks still want magnetic ink. Our advice:

• Use MICR toner if you print more than a few checks a month or if your bank asks for it.
• Whatever toner you use, print at 100% scale and run an alignment test first.
• Ask your bank to scan a test check before you pay real bills.

Protect your account

• Store blank check stock and printed checks securely; treat them like cash.
• Use stock with security features and fill the amount line with asterisks (the tool does this).
• Ask your bank about positive pay: you send the list of issued checks and the bank flags any check that doesn't match. Export it from the check register.

Questions