Free SKU Generator: Use a Spreadsheet Formula Instead

How to get SKU codes without paying for software

Last updated: August 2026

Bottom line: a spreadsheet column and a five-part naming rule does everything a free SKU generator does, and for a seller holding 400 items it takes about twenty minutes to set up once and nothing at all to maintain. SKU codes are not a technology problem — they are a naming convention, and the tools that generate them are mostly solving the trivial half.

The useful half is deciding what the code should encode. A random string like A7X2K9 is unique and tells you nothing. A code like WC-LEV-32-G0421-B14 tells you it is womens clothing, Levi brand, size 32, from the Goodwill lot bought in April, sitting in bin 14 — and it does that from a packing slip, without opening a database.

That difference is what separates a working system from a column of noise, and no free SKU generator can make that decision for you.

What the code should actually carry

Five fields cover almost every resale operation. Category, so you can group and count without filtering. Brand, abbreviated to three or four letters. Size or variant, which is what you will be asked about most often. Source and date, usually the lot or supplier plus a month code, because that is how you work out which sourcing decisions paid.

And location, which is the field that saves the most time day to day, because finding the item is the slow part of fulfilling an order.

Length matters more than people expect. Under about twenty characters stays readable on a label and typeable by hand when the scanner fails; past thirty it becomes something you copy and paste and never actually read, at which point you have rebuilt the random string with extra steps.

A seller processing 200 orders a month who can locate an item from the code alone saves somewhere around three to four hours monthly against one who has to look it up.

The genuine reason to reach for a free SKU generator is bulk creation — producing 500 sequential codes for a pallet at once rather than typing them. That is a spreadsheet fill-down, and the section below shows the formula.

How the options cost out over a year

Bottom line: the spreadsheet route costs $0 in software and about 20 minutes of setup, while inventory platforms that include SKU generation run $180 to $600 a year — and for anything under roughly 1,000 items the paid tools are buying you features you will not use.

Why the web tools score badly on time

The counterintuitive line in that table is the online free SKU generator taking longer than the spreadsheet. The reason is transfer: a web page produces codes on screen, and those codes then have to get into the sheet where your inventory actually lives. That is a copy, a paste, and usually a reformat, repeated per batch.

A formula in the sheet writes the code exactly where it is needed and fills down 500 rows in one drag.

The paid platforms are not overpriced — they are simply solving a different problem. What you get for $180 to $600 is barcode scanning, multi-location tracking, purchase order handling and integrations. A seller holding 3,000 items across two storage units needs that.

A seller with 400 items in a spare room is paying for infrastructure to manage a problem they do not have, and the free SKU generator question is really a proxy for asking whether they have crossed that threshold yet.

There is a switching cost worth pricing before you commit to anything. Moving 400 items from one coding scheme to another means relabelling every physical item, which at roughly forty seconds each is close to four and a half hours of work that produces no new inventory and no new sales.

That is the real argument for spending twenty minutes on the naming rule at the start rather than adopting whatever a tool hands you: the cheap decision is the one you do not have to redo. Sellers who start with a random-string free SKU generator and later want readable codes pay that four-hour bill in full.

One cost applies whichever route you choose: the label printer and stock, at $100 to $180 once and roughly two cents a label. Codes that exist only in a spreadsheet and not on the physical item solve half the problem, because the time you were trying to save was spent looking through bins, not looking through files.

, according to National Retail Federation research

Quick tangent — I use the Closo Seller Hub to track what is actually moving right now, which saves me about three hours a week of manual search. Worth a peek before your next haul.

How to judge whether a coding scheme will survive contact with your inventory

Bottom line: the test of a SKU scheme is whether you can locate an item and recall what it cost from the code alone — a seller who can do that fulfils an order in about ninety seconds, and one who cannot spends four to six minutes per order hunting. Across 200 orders a month that is the difference between five hours and seventeen.

Start with uniqueness, because it is the requirement everything else depends on. Two items sharing a code is not a small annoyance; it is a mis-shipment, a return, and a buyer who tells the world about it.

Any free SKU generator will guarantee uniqueness by throwing random characters at the problem, and that works — but a sequential counter inside your own scheme achieves the same thing while staying readable, and a duplicate then becomes impossible rather than merely improbable.

The second test is human readability under pressure. At the packing table you are holding a garment and looking at a label, sometimes with a scanner that has decided not to cooperate.

A code you can read aloud and type in five seconds keeps working in that moment; a twelve-character random string does not, and the failure lands precisely when you are busiest. This is the strongest practical argument against the output of most free SKU generator tools: they optimise for machine uniqueness in a workflow that is still substantially human.

The field most schemes leave out

Location is the one that pays for itself fastest and the one people forget. Encoding the bin, rail or shelf directly into the code means the packing slip tells you where to walk. Without it, you are consulting a second system — or worse, memory — for every order.

Sellers who add a location field typically report the largest single time saving of any change they make to their inventory process, and it costs three characters.

When considering sku generator app, When considering define sku number, When considering custom sku generator, When considering best free sku generator, Cost is the second omission, and it is the one that quietly damages decisions rather than time. If the code carries a source and month — the lot, the supplier, the date — then a year later you can group your sales by where the goods came from and see which sourcing actually paid.

A seller who discovers that one supplier returns $18 average margin and another returns $4 has learned something worth more than every hour of packing time saved. A free SKU generator producing anonymous strings cannot give you that, because the information was never encoded to begin with.

The third test is stability. Schemes break when they meet something they were not designed for: a bundle of five items sold as one, a returned item that needs a new code, a lot with 300 identical units.

Decide those cases at the start — a bundle prefix, a return suffix, a quantity field — because retrofitting them across 400 already-labelled items costs about four and a half hours of relabelling and produces nothing.

Finally, check that the scheme survives growth. Two-character category codes run out faster than expected, and a seller who used single digits for bins discovers the problem at bin ten. Build in one more character than you currently need in every field.

The cost of that decision is zero today and the cost of not making it is a full recode later, which is the same four-and-a-half-hour bill in different clothing.

Run all four tests against whatever a free SKU generator hands you before adopting its output wholesale, because the tool is answering a narrower question than the one your inventory is about to ask.

How to answer the questions that come up while setting this up

Bottom line: six questions cover the setup, and the one worth getting right first is whether the code needs to mean anything — because that decision is expensive to reverse across an already-labelled inventory., according to Federal Trade Commission consumer guides

What formula generates codes in a spreadsheet?

Concatenate your fields with a separator and add a sequential number. Something of the shape =A2&"-"&B2&"-"&TEXT(ROW()-1,"0000") joins a category column, a brand column and a four-digit counter, then fills down as far as you drag it.

That is the entire mechanism behind any free SKU generator, running inside the sheet where your inventory already lives, which removes the copy-and-paste step that makes the web versions slower in practice.

Should SKU codes be random or meaningful?

Meaningful, for a resale operation. Random strings are fine when a scanner does all the reading and a database holds the meaning, which describes a warehouse rather than a spare room.

A code you can read from a packing slip tells you where to walk and what the item is without opening anything, and that saves three to four hours a month at 200 orders.

Random codes give that up in exchange for uniqueness you can get from a counter anyway, which is why the output of a typical free SKU generator suits a warehouse better than a resale bench.

Do marketplaces use my SKU codes?

Most let you attach a custom label or SKU field to a listing, and it is visible to you rather than to buyers. That field is what makes the whole system pay off, because the code then travels onto the order and the packing slip.

A code sitting only in your own spreadsheet, never entered on the listing, means you still have to look each order up — which is most of the work you were trying to remove.

How do I handle bundles and returns?

Decide before you need it. A bundle usually gets its own code with a prefix marking it as a bundle, and the component codes recorded against it so the individual items are accounted for. A returned item generally keeps its original code with a suffix, which preserves the sourcing history while flagging that it has been round the loop once.

Retrofitting either convention later means relabelling everything, at roughly forty seconds an item.

Is a paid tool ever the right answer?

Past roughly 1,000 items, or once you are running more than one storage location, yes. At that scale barcode scanning and multi-location tracking stop being luxuries. Below it, a free SKU generator or a spreadsheet formula does the same job, and the $180 to $600 a year is better spent on inventory.

How to set this up in the next twenty minutes

Bottom line: twenty minutes on the naming rule now saves about four and a half hours of relabelling later and three to four hours a month in packing time — which makes it one of the highest-return twenty minutes available in a resale operation.

Open your inventory sheet and add five columns: category, brand, size or variant, source and month, location. Fill them for the items you already have, which is the only genuinely tedious part. Then add a SKU column with a concatenation formula and a sequential counter, and drag it down.

That is the whole build, and it does everything a free SKU generator does while writing the result directly where you need it.

Then make the code actually travel

Two steps turn the scheme from a spreadsheet exercise into a time saving. First, print the code on a label and put it on the physical item, because the minutes you are trying to recover are spent looking through bins rather than through files.

Second, enter the code in the custom SKU field of each marketplace listing, so it lands on the order and the packing slip. Skip either and you have built a system you still have to look things up in.

Give every field one more character than you need today. Two-digit bins run out at bin ten, three-letter brand codes collide sooner than expected, and expanding a field after 400 items are labelled costs the four and a half hours the whole exercise was meant to avoid.

A free SKU generator will not warn you about that, because it does not know how many bins you plan to have.

Guides on inventory tracking, sourcing analysis by supplier, and running one catalogue across eBay, Poshmark, Mercari and Depop simultaneously are on the Closo blog hub.

Keep going: Closo Seller Hub · Closo Demand Insights · Closo Crosslister.