Fixed-Width File Inspector
Paste a fixed-width positive pay file and this inspector reports the line count, checks whether every record is the same length, flags blank or short lines and stray trailing characters, and shows a character-position ruler so you can line up each field against your bank's spec.
Unequal record length is the single most common reason banks reject a fixed-width positive pay file. This tool finds that problem, and several related ones, before you upload.
Why record length is the most common rejection
In a fixed-width file, every record is a single line and every field occupies a fixed number of character positions. The total width of all fields must equal the record length in your bank's spec. If one line is even a single character too long or too short, the fields after that point shift, and the bank's parser reads the wrong data in the wrong columns. That is why an uneven record length is the top cause of a rejected file. The inspector checks the length of every line and tells you which ones do not match the rest, so you can fix the outliers instead of guessing.
For background on why these files are length-sensitive and how they differ from comma-separated layouts, see fixed-width vs CSV positive pay files. If your bank has already bounced a file, the checklist in why your positive pay file was rejected walks through the usual causes in order.
Blank lines, short lines, and trailing characters
Beyond record length, a few small defects break fixed-width files quietly. A blank line, often an empty final line, can be read as a malformed record. A short line that is missing trailing spaces fails the length check even when the data looks complete on screen. And trailing characters, such as a stray space, tab, or carriage return at the end of a line, change the byte count without being visible. The inspector flags each of these so you can clean them up. It also makes whitespace at the ends of lines easy to spot, since that is where these problems usually hide.
Lining up fields with the ruler
The character-position ruler numbers each column so you can lay a record against your bank's field map. If the spec says the amount field starts at position 30 and runs 10 characters, you can confirm your digits land in positions 30 through 39 and nowhere else. Many layouts store the amount with an implied decimal, so the ruler helps you verify the digits fill the field exactly with no stray decimal point. To match field names and positions to your bank, use the file format reference and the positive pay glossary.
From inspection to a clean upload
Once the inspector confirms equal record length and no blank, short, or trailing-character problems, your file is ready to send. If you would rather not hand-build the layout, the positive pay file generator produces correctly padded fixed-width records for you, and the validator double-checks them. See the full free tool list for related checks like the gap finder and MICR decoder.
Frequently asked questions
What does the fixed-width file inspector check?
It reports the total line count, checks whether every record has the same length, flags blank and short lines, highlights stray trailing characters, and shows a character-position ruler. Together these catch the defects that most often cause a bank to reject a fixed-width positive pay file.
Why does my bank reject a file when one line is a different length?
Fixed-width parsers read each field from fixed character positions. If one line is longer or shorter than the rest, every field after the difference shifts into the wrong columns, so the bank reads bad data. Equal record length on every line is required, which is why the inspector checks each line's length.
How do I find an invisible trailing character?
The inspector flags lines with trailing spaces, tabs, or carriage returns that add to the byte count without showing on screen. It surfaces end-of-line whitespace so you can delete the extra characters and bring the record back to the correct length.
What is the character-position ruler for?
The ruler numbers each column so you can line a record up against your bank's field spec. If the amount field is defined as positions 30 to 39, you can confirm your digits fall exactly in that range. It is the fastest way to verify field alignment without counting by hand.
Does a short line really cause a rejection if the data looks complete?
Yes. Fixed-width fields are padded to a fixed width, usually with trailing spaces. A line that is missing that padding is shorter than the record length even though the visible data looks complete, and the bank's length check will fail. The inspector flags these short lines so you can pad them.
Is my file uploaded anywhere when I use this tool?
No. The inspector runs entirely in your browser, so the file you paste never leaves your computer. It is part of the free PositivePayMaker toolset alongside the file generator and validator.