How to Check Warehouse Label Data Before Printing
Most rack label reprints start in the spreadsheet, not on the press. Getting rack labels right the first time is where the savings are. For Zion Solutions Group, a supply chain automation integrator, running their location data through the CIS Label Data Validator before print caught errors that would have meant about $15,000 in reprints. The usual culprits are simple: a duplicate code, a gap in the bay sequence, or a column of location codes that lost its leading zeros. They all print perfectly and fail on the floor. This page shows how to check a location file yourself, step by step, and how CIS checks it with the CIS Label Data Validator, which runs 16+ automated checks.
The short version
- Work from one master location file
- Check for duplicate location codes first
- Find sequence gaps and confirm the intentional ones
- Keep fixed-width formats and leading zeros (format cells as text)
- Verify check digits, arrows, and level codes
- Print and scan a pilot set before full production
For Zion Solutions Group, a supply chain automation integrator, running their location data through the CIS Label Data Validator before print caught errors that would have meant about $15,000 in reprints.
Why rack label reprints start in the spreadsheet
A label printer does exactly what the file tells it to do. If the file is wrong, every label made from it is wrong in the same way, and nobody finds out until the labels are on the rack.
The waste is easy to picture. A duplicate code turns into pick and putaway errors the day the labels go up. A gap leaves a real location with no label at all. A format change halfway down the file gives you two styles of code in one building. Fixing any of these after install means pulling labels off steel in a working warehouse and paying for the run a second time.
Catching the same error in the file costs far less. That is the whole case for checking first. For Zion Solutions Group, a supply chain automation integrator, running their location data through the CIS Label Data Validator before print caught errors that would have meant about $15,000 in reprints. Every run is different, so treat that as one customer's result, not a promise. For the bigger picture, see warehouse rack labeling best practices and how location labels cause mispicks.
Common errors to check for
Duplicate location codes
Two rows with the same code. Example: A01-03-B appears in aisle 1 and again further down the file after two exports were merged. This is the most expensive error on the list, because each duplicate becomes a pick or putaway error once the labels are up.
Near-duplicate typos
Codes that look right but aren't. The letter O typed in place of a zero (A0O-03-B), or two digits swapped (A01-12-B where A01-21-B was meant). They pass a quick glance and send pickers to the wrong place.
Sequence gaps
Missing bays or levels in a run. If bays go 01, 02, 04, either bay 03 is missing from the file or it doesn't exist. Odd and even numbering makes this tricky: when one side of the aisle is odd and the other even, a jump from 01 to 03 is normal. Confirm every gap is intentional.
Format inconsistencies
A-01 on some rows and A1 on others. Different separators, different zero padding, different letter case. The WMS may treat them as different locations, and the labels look mismatched on the rack.
Lost leading zeros and Excel auto-formatting
Excel treats 0101 as a number and stores it as 101. Long numeric codes can turn into scientific notation, and codes like 1-2 or 3/4 can turn into dates. Format the column as text before you paste or import, and check a few rows after every save.
Check digit errors
A check digit is an extra character calculated from the rest of the code, so the scanner or WMS can catch a mistyped or swapped location. If you use them, recompute every one after any change to the file. A stale check digit causes more trouble than none at all.
Arrow and level mismatches
Arrow direction or level codes that don't match the rack. Example: a label meant for the slot above the beam carries a down arrow, or labels for level C are tagged as level B in the file.
Location-type outliers
A code that doesn't belong where it sits. Example: a shelving code in the middle of a pallet rack aisle, or a floor location code in a run of beam labels.
Formulas and pivot-table leftovers
Cells that look like codes but hold formulas, subtotal rows left over from a pivot table, or hidden rows. Paste values only into the final file.
How to check your file yourself, step by step
- Freeze one master file. Pick one file as the source of truth, name it clearly, and stop editing other copies.
- Format the location column as text before pasting. In Excel, select the column, choose Format Cells, then Text. Do it before you paste or import so leading zeros survive.
- Find duplicates. Use Conditional Formatting, then Highlight Cells Rules, then Duplicate Values. Or add a helper column with =COUNTIF(A:A,A2) and filter for anything greater than 1.
- Sort and look for gaps. Sort by aisle, then bay, then level. Read down each aisle for missing numbers, and confirm which side of the aisle is odd and which is even.
- Check length and pattern. Add a helper column with =LEN(A2) and look for any code that is longer or shorter than the rest. Then check the separators and letter positions.
- Recompute check digits. If you use them, recalculate every check digit from the final codes instead of trusting old values.
- Spot-check arrows and levels. Pick a few bays in each aisle and compare the arrow and level fields with the rack drawing.
- Print and scan a pilot. Print labels for one aisle, put them up, and scan them with your own scanners and WMS. Fix anything that fails before you print the rest.
How the CIS Label Data Validator helps
What it is
A CIS tool that checks warehouse location label files for errors before production.
What it checks
16+ automated checks, including duplicates, sequence gaps, and format errors.
How to get your file checked
Email your location file to keaton@innovationandsupply.com with your quote request. Send it the way your WMS or spreadsheet exports it. We will tell you what we found so your team can fix it before anything prints.
Prefer to check it yourself first? Use the CIS Label Data Validator.
Send us your label data file for a pre-print check.Data check, proof, then scan test
The data check is the first of three gates. First, check the data. Second, approve a proof, so you see exactly how codes, arrows, and colors will print. Third, scan a pilot set on the rack with your own scanners and WMS. Only then produce the full run.
The warehouse label installation guide covers what happens after that, and the new warehouse labeling checklist puts the whole sequence in project order for a new building. Replacing labels in a running building? Check the data before you reprint. For the file layout itself, see the data file quick reference in the Warehouse Label and Sign Selection Matrix, and for why price comparisons miss this step, read why multiple quotes won't save you money if your data is wrong.
Labeling a warehouse in Atlanta or North Georgia?
CIS is based in Winder, Georgia, and works with facilities across metro Atlanta and North Georgia. Ask for a data check with any rack labeling quote. See warehouse rack labels in Atlanta and Georgia, or browse our warehouse barcode labels.
15+ years in business | 500+ clients | 10K+ products delivered
Frequently asked questions
How do I check warehouse label data before printing?
Work from one master file. Check for duplicate codes, sequence gaps, inconsistent formats, lost leading zeros, and check digit errors, then print and scan a pilot set before full production.
How much can catching label data errors before print save?
It depends on the size of the run. For Zion Solutions Group, a supply chain automation integrator, running their location data through the CIS Label Data Validator before print caught errors that would have meant about $15,000 in reprints.
What is the most common error in rack label data?
Duplicate location codes. Each duplicate becomes a pick or putaway error once the labels are on the rack.
Why do my location codes lose their leading zeros?
Excel treats them as numbers. Format the column as text before you paste or import.
What is a check digit on a warehouse location label?
An extra character calculated from the rest of the code. It lets the scanner or WMS catch a mistyped or transposed location.
What is the CIS Label Data Validator?
A CIS tool that runs 16+ automated checks on warehouse location label files, catching duplicates, sequence gaps, format errors, and more before the labels go to production.
How do I get my file checked by CIS?
Email your location file to keaton@innovationandsupply.com with your quote request, or send it through our contact page. Keaton replies the same business day.
What should my location data file look like?
One row per location, with the location code stored as text and the same format on every row. Most teams export it from their WMS or a spreadsheet.
Send your file or get a same-day quote
Keaton replies the same business day. Call 770-561-5285 or email keaton@innovationandsupply.com.