A check is the same handful of parts no matter who printed it. There's the date, the payee on the “Pay to the order of” line, the amount written twice (once in a number box, once in words), your signature, and, along the bottom, three numbers: the routing number, the account number, and the check number. Learn those and you can read any check. The reason to keep reading past that is that a check isn't just a form, it's a legal order to your bank to pay money, and several of its parts do something other than what a quick glance assumes.
A check has three parties, which is worth naming because the rest of the guide uses them: the drawer is you, the person who writes and signs it; the drawee is your bank, the one ordered to pay; and the payee is whoever you're paying. Hover or tap any field below to see what it does; the section-by-section reference follows.
- Top-rightCheck number
- The check's serial number. It should match the last group in the MICR line at the bottom; a mismatch is a tampering flag.
- Top-rightFractional routing number
- The old fraction-format bank ID, kept as a manual backup for when the MICR line is torn or unreadable. It encodes the same routing information as the nine-digit number below.
- Top-rightDate
- When the check was written. A bank isn't required to pay a check more than six months after this date, but it may. Postdating doesn't reliably stop early payment.
- Line 1Payee ('Pay to the order of')
- The one person or business allowed to deposit or cash the check. Only the payee can endorse it over to someone else.
- BoxCourtesy amount (number box)
- The amount in figures. It's a convenience for quick reading and is NOT the legally controlling amount.
- Line 2Legal amount (written line)
- The amount in words. If it disagrees with the number box, this is the amount the bank must pay. Cents are written as a fraction over 100.
- LineMemo / For line
- An optional note for the writer's own records: an invoice or account number, or what the check is for. It has no legal effect on payment.
- Bottom-rightDrawer signature
- Signed by the account holder (the drawer). An unsigned check isn't valid. Banks may check it against the signature on file.
- FrontBank name
- The bank the check is drawn on (the drawee). The printed name does not carry the routing number; that lives in the MICR line.
- MICRRouting number
- Nine digits identifying your bank, bracketed by the transit symbol. The ninth digit is a check digit you can verify by hand (below).
- MICRAccount numbercheck it
- Identifies your specific account, marked off by the on-us symbol. Sensitive: routing plus account number is enough to attempt an ACH debit.
- MICRCheck number (in the MICR line)
- The serial number repeated in the bottom line. On business checks it sits in its own field at the far left; on personal checks it follows the account number.
Most guides stop at labeling those parts. The rest of this one is what they mean when it matters: which of the two amounts the bank is actually bound to pay, the one digit in the routing number that exists only to catch a typo, why an old check isn't dead but isn't guaranteed either, what happens to the paper after you deposit it, and how to read a check for the signs that it's been washed and rewritten.
The three numbers at the bottom: routing, account, check
The line of slightly odd-looking digits across the bottom of a check holds three numbers, and reading them left to right: the routing number (nine digits, which bank), then your account number (which account), then the check number (which matches the one in the top-right corner). The routing number is always nine digits; the account number's length varies by bank, usually 8 to 12 digits.
The routing number is not a random ID. It's a structured code the American Bankers Association and the Federal Reserve assign, and its nine digits break down like this:
| Position | What it encodes |
|---|---|
| Digits 1 and 2 | The Federal Reserve Bank (district) number. 01 through 12 map to the twelve Federal Reserve districts; other ranges are reserved for thrifts and electronic transactions. (These two digits plus the next two are together called the routing symbol.) |
| Digit 3 | The Federal Reserve check-processing center originally assigned to the bank. |
| Digit 4 | 0 if the bank sits in the Federal Reserve district's head-office city, otherwise a 1 through 9 tied to its state. |
| Digits 5 to 8 | The specific bank's own identifier within that district (its ABA institution number). |
| Digit 9 | The check digit: a self-check computed from the other eight, so software can reject a mistyped or invented routing number. |
That last digit is the interesting one. It's a check digit, computed from the other eight by a fixed formula, and its whole job is to let software reject a mistyped or made-up routing number before anyone tries to move money. You can verify it by hand. Take the digits and apply the weights 3, 7, 1, repeating, then add the results; a valid routing number's total is always a multiple of 10. Using the real number on the sample check above, 111000025:
- 3 × (1 + 0 + 0) = 3
- 7 × (1 + 0 + 2) = 21
- 1 × (1 + 0 + 5) = 6
Add them: 3 + 21 + 6 = 30, which is a multiple of 10, so the number passes. Change any single digit and the total stops landing on a multiple of 10, which is exactly how a bank's systems, and the deposit form in your banking app, catch a routing number you fat-fingered.
There's a second, older copy of the routing information on the check: the fractional routing number, the little number that looks like a fraction printed up near the check number (something like 66-71/510). It predates the magnetic line at the bottom (the American Bankers Association created the fraction system in 1910) and it encodes the same Federal Reserve routing information. It hangs on as a manual backup: if the bottom line is torn or smudged, a person can still route the check from the fraction. You'll almost never use it yourself.
One practical trap: the routing number printed on your check is your bank's number for paper checks and ACH (direct deposit, autopay). Some banks, often the large ones, use a different routing number for domestic wire transfers, because wires clear over a separate Federal Reserve system. So if someone asks for your routing number to send a wire, don't just read it off a check; confirm the wire routing number with your bank, or it can bounce.
The account number is the sensitive one. Routing number plus account number is all it takes to attempt an ACH debit, which is exactly the information a check hands over in plain sight to anyone who sees it. That's not a reason to fear checks, but it is the reason to treat a check, or a photo of one, as a document you send carefully, not something to text or leave in an email inbox. The check number is the least sensitive: it's just a sequential label for your own record-keeping. It appears in two places, printed in the corner and again in the bottom line, and those two should match. A mismatch is a small but real sign the check has been tampered with.
The MICR line, and why it's printed in magnetic ink
That bottom line has a name almost no guide mentions: the MICR line, for Magnetic Ink Character Recognition. It's printed in a special font (E-13B in the US) using ink that contains iron oxide, so it's magnetic. That's not decoration. Sorting machines read the line magnetically, which means they can still read it from a check that's been folded, stamped, or written across, where an ordinary optical scan would fail.
The blocky characters between the numbers are four special symbols that tell the machine which field is which:
| Symbol | What it delimits |
|---|---|
| Transit | Brackets the routing number so a sorting machine knows where the nine-digit bank code starts and ends. |
| On-Us | Marks off the bank-specific fields, chiefly your account number (and, on a personal check, the check number that follows it). |
| Amount | Brackets the dollar amount. It isn't pre-printed: the first bank to process the check encodes the amount here in magnetic ink. |
| Dash | Separates parts of a number within a field. |
One consequence is worth knowing: a plain photocopy of a check usually won't process, because a copier uses ordinary toner and the copied MICR line isn't magnetic. That's a deliberate anti-fraud property, not a bug, and it's part of why a genuine check and a color copy of one are not interchangeable at the bank even though they look identical.
Why the words beat the numbers
A check writes the amount twice: once as a figure in the box (the courtesy amount) and once spelled out on the line (the legal amount). If the two ever disagree, here's the rule almost nobody states: the words win. Under the Uniform Commercial Code, the model law every US state has adopted, when a check has contradictory terms the words prevail over the numbers, and handwriting prevails over both typing and printing (that's section 3-114, if you want to look it up in your own state's version). So the amount your bank is bound to pay is the one written out on the line. The number in the box is a convenience for fast reading.
That isn't trivia. It's why the written line is the one that matters when a check is altered, and why you fill it out with the same care you'd give a contract: write the amount starting hard at the left, and draw a line through any empty space after it so no one can add a word. It's also a small piece of self-defense when you're the one receiving a check. If the box says $1,450.00 but the line says “fourteen hundred and fifty,” the line controls, and it's worth resolving before you deposit rather than after.
The date line: the six-month rule and postdating
A check does not expire on a fixed date, but this is the part people get wrong in both directions: a bank is not required to pay a check more than six months old, and an old check is not automatically void. Under the Uniform Commercial Code (section 4-404), a bank is “under no obligation” to pay a personal check presented more than six months after its date, but it may still pay it in good faith and charge the account. So a stale check sits in a gray zone: it might clear, it might get bounced back, and which one happens is up to the bank. If you're holding a check that's aged past six months, don't assume either outcome. Ask whoever wrote it to void it and reissue a fresh one. (Cashier's checks, money orders, and government checks follow their own rules and often stay valid longer.)
Postdating(writing a future date to say “don't cash this until then”) is weaker than most people think. A demand check technically isn't payable before its date, but under the Uniform Commercial Code a bank can pay a postdated check early anyway unless you gave the bank specific advance notice describing the check. In practice, most banks' automated systems don't even read the date when a check is deposited, so a postdated check often clears the day it's deposited. If the timing genuinely matters, don't rely on the date; keep the money in the account or don't hand over the check until you mean it.
The back of the check, and what happens after you deposit it
The back of a check is mostly one thing: the endorsement, where the payee signs before depositing or cashing. How you sign changes what the check can do, and there are three ways to do it.
| Endorsement | What you write | What it does |
|---|---|---|
| Blank | You just sign your name on the back. | The check becomes payable to whoever holds it, so a blank-endorsed check that's lost is close to cash. Sign at the moment of deposit, not before. |
| Special | 'Pay to the order of [name]', then your signature. | Signs the check over to a specific person, who then has to endorse it themselves to deposit or cash it. |
| Restrictive | 'For deposit only' with your account number, then your signature. | Directs the check into that one account. It's the safest way to endorse a check you're mailing or dropping in an ATM, though it doesn't legally freeze all further transfer the way people assume; its real effect is on how the bank must apply the funds. |
You'll also see instructions printed on the back now, like a “For mobile deposit only” box to check when you deposit by phone photo, and a security screen, wording or a pattern that fades or reads VOID when the check is copied. Those are there because of what happens next.
Here's the part that surprises people: you almost never get the paper check back anymore. Under the Check Clearing for the 21st Century Act(“Check 21”), which took effect on October 28, 2004, your bank can clear a check from a digital image and destroy the paper. What you can get in its place, if you ask, is a substitute check: a paper reproduction of the front and back plus the MICR line that federal law treats as the legal equivalentof the original, as long as it carries the legend “This is a legal copy of your check. You can use it the same way you would use the original check.” For everyday purposes, the image in your banking app does the same job, which is why you should download the ones that matter rather than assume they'll be there forever.
Check 21 also gives you a consumer protection worth knowing: if a substitute check was posted to your account incorrectly, you can claim expedited recredit. Make the claim and the bank generally has to put the money back, up to the lesser of the disputed amount or $2,500 plus interest, by the tenth business day while it investigates, with any remainder by the 45th calendar day. It's the check-image equivalent of the dispute rights you have on a bank statement.
How to spot a fake or washed check
Checks are a shrinking share of how America pays, and that's exactly why this matters. The Federal Reserve's 2025 payments study, published in July 2026, found checks fell to just 4% of US noncash payments by number in 2024, down from 59% in 2000. But check fraud is going the other way. FinCEN reported that financial institutions filed more than 680,000 check-fraud suspicious activity reports in 2022, nearly double the roughly 350,000 filed in 2021 (FinCEN alert, February 2023). A later FinCEN analysis tied more than $688 million in suspicious activity to mail-theft check fraud over a single six-month window in 2023. Fewer checks, more fraud, so the ability to read one for authenticity is more useful now, not less.
The dominant scam is check washing: a thief steals a check in the mail, chemically erases everything but your signature, and rewrites the payee and the amount. Remember that the written line is the legally controlling amount, so an altered words line is what actually moves the money. A few habits blunt the whole category:
- Write with a gel pen. Gel ink pigment locks into the paper fibers and resists the solvents used to wash a check; ballpoint ink lifts off more easily.
- Fill the whole legal-amount lineand strike a line through any leftover space, so no one can extend “fifty” into “fifty-five hundred.”
- Don't mail checks from your home mailbox. Drop them inside the post office. A raised flag on a residential box is an advertisement.
To read a check you've received for signs it's fake or altered, use the features built into a genuine check: microprinting(a line or the letters “MP” that looks solid but is tiny text under a magnifier, and turns to a blurry dashed line on a photocopy), a padlock icon indicating the check meets industry security standards, and the security screen on the back. Confirm the printed check number matches the one in the MICR line, and be wary of a payee or amount that looks retraced or sits in ink that doesn't match the rest of the writing. If you run a business and write checks, ask your bank about positive pay, a service where you register the checks you've issued so the bank flags any that don't match what you told it.
How long to keep a check
Most cleared checks you don't need to keep at all once they show up on a bank statement you've reconciled. The ones worth holding are the checks that prove something: a check tied to a tax deduction, a large purchase, a loan payoff, a down payment, or an open dispute. Keep those for about seven years, the same window that covers a tax record, and longer if they document ownership of something you still own. Our retention guide has the full table.
Because banks destroy the paper, your record of a check is the image in your banking app or the substitute check, and banks only keep those available for a limited window. So the checks that matter are worth pulling down and filing, not leaving on the bank's server. That's the small job Granite is built for: drop in a check or a photo of one and it reads it, pulls out the payee, the amount, the date, and the account, and files it, so later you can ask who you wrote check 1042 to, or how much you paid a landlord last year, and get the answer with a citation to the check itself. To be clear about what it is and isn't: Granite reads and files the checks you keep or receive and makes them findable; it is not your bank, it doesn't cash, deposit, print, or send checks, and none of this is legal advice. For the record it belongs to, read it alongside the check reference page and your bank statement, where every check you write and deposit eventually lands.