What Is a Check Issue File?
A check issue file is the list of checks your business has written that you send to your bank. The bank stores that list and compares every check presented for payment against it. If a check clears that does not match a record you sent (wrong amount, unknown check number, an account you never use), the bank flags it instead of paying it. That comparison is the core of positive pay, the main defense banks offer against altered and counterfeit checks.
You will see the same thing called several names depending on the bank: check issue file, issued check file, issue file, or check-issued report. They all mean the same upload. Most banks expect you to send a fresh file every time you cut a batch of checks, often daily, before those checks reach the bank for payment.
What a check issue file actually contains
The data is simple. Each row describes one check. Across nearly every bank, a check issue file carries some combination of these fields:
- Account number, the checking account the check is drawn on.
- Check number, the unique serial number printed on the check.
- Check amount, the dollar amount, which the bank matches against the amount presented.
- Issue date, the date the check was written.
- Payee name, who the check is made out to. Some banks require this for "payee positive pay," which also verifies the name; others ignore it.
- Issue or void code, a flag, often a single letter or word, that tells the bank whether this row is a new check ("I" or "Issue") or a check you are voiding ("V" or "Void"). Not every layout uses this.
The first four are the load-bearing fields. Account number, check number, and amount are what the bank matches on, and a mismatch on any of them is what stops a suspect check. Some layouts add a transaction code, a void date, or padding columns the bank simply ignores. If your accounting export includes extra fields, most banks will skip them as long as the columns they need are present and consistently placed.
The two file formats banks ask for
Banks accept check issue files in one of two physical layouts. Knowing which one yours wants saves a lot of rejected uploads.
Delimited (CSV)
A CSV separates each field with a comma. One row, one check. It looks like this:
123456,11/26/2025,John Doe,2500.00,987654321
CSV is forgiving because the comma marks where each field starts and ends, so column widths do not have to be exact. Excel files (.xls/.xlsx) are a close cousin; many banks accept those too and treat them like a spreadsheet version of the same rows.
Fixed-width (fixed-length)
A fixed-width file gives every field a set number of characters and pads the rest with spaces or zeros. There are no commas. The same check might look like this:
123456 11262025John Doe 0000025000987654321
Here the bank reads "positions 1 through 10 are the check number, 11 through 18 are the date," and so on. Fixed-width is unforgiving: if a field lands one character off, the whole file fails. When your bank gives you a fixed-width spec, it will list the start position and length of every field. Match those exactly.
Every bank defines its own field order, date format, and whether amounts include the decimal point or are sent in cents. There is no single national standard. That is why a file built for one bank usually will not load at another without changes.
Where the file comes from
Your check issue file is built from your check register, the running record of checks you have written. The catch is that most accounting software will not produce the file in your bank's exact layout. QuickBooks, for example, cannot export a positive pay file natively. You can run a Check Detail report and export it to Excel, but that gives you raw columns, not your bank's required field order, date format, or fixed-width positions. The gap between "list of checks I exported" and "file my bank will accept" is exactly the work a conversion tool does.
You have a few ways to close that gap:
- Reformat by hand in a spreadsheet. Workable for a handful of checks, error-prone and slow once volume climbs.
- Use a free browser converter. PositivePayMaker takes your CSV or Excel check register and outputs a file in your bank's layout. It runs entirely in your browser, so your check data never leaves your computer. It ships with 11 bank layouts (six built from published bank specs, including Chase and Huntington), a custom format builder for matching any other layout, and a validator to check a file before you send it.
- Buy a desktop tool. Big Red Consulting's PositivePay File Creator runs about $119 the first year and $99/year after, Windows-only, with the QuickBooks Online edition requiring Excel installed. Treasury Software's Bank Positive Pay is an installed Windows product priced roughly $29.95 to $89.95 per month with hundreds of bank layouts preloaded. MoneyThumb and ProperSoft sell paid desktop converters as well. For a high-volume team that needs hundreds of bank layouts maintained for them, a paid tool can be worth it. For most small businesses sending one bank's format, a free converter does the same job.
Getting the first file right
The single most important step is verification. Before you rely on any new file, generate one and send it to your bank, then confirm with your treasury or business-banking contact that it loaded cleanly and the checks matched. A check issue file that the bank silently rejects is worse than none, because you may believe your checks are protected when they are not. Banks publish their exact layout through their treasury or business-banking portal; if you cannot find it, ask your relationship manager for the file specification document.
Once you know your bank's required fields and format, building the file becomes routine. Export your register, map it to the layout, validate, and upload.
For a deeper look at how the bank uses this file to catch fraud, see our positive pay overview. When you are ready to convert your register, the PositivePayMaker tool handles the formatting for you.