For most small producers there's no difference: a batch number and a lot number are both the code for one production run, and you can use either word. Even FDA's drug rules, the strictest place these terms are defined, put "lot number, control number, or batch number" under one definition. The two only part ways when one batch is packed in pieces, say mixed on Monday and bottled over Monday and Tuesday. Then the batch is what you mixed, and each packing run is a lot.
The short version
- Same thing, in most small businesses. One run, one code.
- When they differ, a lot is a batch or a piece of one. The batch is the mix; the lots are the pack runs.
- A serial number is one per unit. A barcode (UPC) is one per product. Neither replaces the lot.
- If a form asks for both and you don't split batches, write the same code in both boxes.
- Whatever you decide, write it down once, in a sentence, and use it on every label and invoice.
- Whichever word you use, TaroStack gives each run its code and keeps the history behind it. The section near the end says how.
What the rules actually say
The definitions most often quoted come from FDA's drug manufacturing rules, and they're worth reading, because they settle the question better than any blog post.
A batch is "a specific quantity of a drug or other material that is intended to have uniform character and quality, within specified limits, and is produced according to a single manufacturing order during the same cycle of manufacture."
A lot is "a batch, or a specific identified portion of a batch, having uniform character and quality within specified limits". (There's a second half for continuous processes, where a lot is an amount made in a unit of time.)
And then the tell. The code gets a single entry: "Lot number, control number, or batch number means any distinctive combination of letters, numbers, or symbols, or any combination of them, from which the complete history of the manufacture, processing, packing, holding, and distribution of a batch or lot of drug product or other material can be determined" (21 CFR 210.3).
Three names, one definition. What matters to FDA isn't the word, it's whether the code leads back to the whole history.
Food rules are simpler still. FDA's preventive controls rule defines a lot as "the food produced during a period of time and identified by an establishment's specific code" (21 CFR 117.3), and the records rule for most food manufacturers and distributors asks for "the lot or code number or other identifier of the food (to the extent this information exists)" (21 CFR 1.337). No batch-versus-lot distinction anywhere.
This is general information, not legal advice. If you're regulated as a drug, supplement or cosmetic maker, your rule's own definitions are the ones that count.
When one batch becomes two lots
A two-person granola kitchen mixes and bakes a 60 lb batch on Monday. That's batch G-0922. It bags in 12 oz bags,
so 80 bags in all, but only gets 40 done before close. The other 40 are bagged Tuesday morning, from the same bin.
Is that one lot or two? It's one batch either way. Whether it's one lot is your call, and here's the argument for
two: Tuesday's bags sat overnight, went through the sealer with a fresh roll of film, and were checked by someone
else. If a customer finds a bad seal on a Tuesday bag, you'd rather pull 40 bags than 80. So Monday's are
G-0922-1 and Tuesday's are G-0922-2, and the batch sheet says both came from G-0922.
It happens the other way round too. Two kettles of sauce blended in one holding tank and bottled together are two batches that became one lot. Write both batch codes on the bottling sheet under the one lot number, and the trace still works.
My suggestion: don't split unless something real changes between the pack runs (a day, a shift, a film roll, a machine). Splitting for the sake of it just gives you more codes to keep straight.
Serial numbers, barcodes and best-by dates
These get confused with lot numbers constantly, usually on the first distributor form.
| Code | Identifies | Changes when | Example |
|---|---|---|---|
| Barcode (UPC/GTIN) | The product | You make a new product or size | Same on every 5 oz bottle of mango habanero |
| Lot or batch number | One production run | Every run | 260921B |
| Serial number | One single unit | Every unit | Rare in food; common on equipment |
| Best-by date | When quality starts to fade | Every run, usually | BB 09/21/27 |
A barcode can carry a lot, though. The GS1-128 format that distributors ask for on cases can hold the product number, the lot and the date in one scannable label, which is where the two systems meet. That has its own article.
And a best-by date can double as a lot code, which works right up until the day you make two batches with the same date. How to create lot numbers compares the common formats, including the Julian date code.
What to write when a form asks for both
If you don't split batches, the right answer is the same code in both boxes, with a line saying so. Buyers read plenty of these. Something like:
Batch and lot numbers are the same at our scale: one code per production run (production date plus a letter, e.g. 260921B), printed on every unit and case and recorded on every invoice.
If you do split, say how: "The batch number identifies the mix; each packing run gets a lot number with a suffix
(G-0922-1), and our batch records link them." Then make sure the next hundred labels say the same thing.
Where this stops working
The words never cause the trouble. The link between them does. When a batch is split and nobody writes down which pack run came from which mix, you have two lot codes and no history, which is worse than one code. The classic version: Tuesday's bags get stamped with Monday's code because nobody moved the date band on the stamp.
The other slow failure is drift. The batch sheet uses one scheme, the label printer another, and the invoices a third, and each looked sensible to whoever set it up. Six months in, "which batch is lot 4471?" has no answer. A lot tracking spreadsheet with one code per row keeps them together, as long as somebody's typing.
How TaroStack does it
Whichever word you settle on, the code only earns its keep if there's a record behind it, and the record is where small makers fall behind. In TaroStack, recording a batch is what gives it its lot code, and the code follows the product from then on: onto lot labels (with GS1-128 barcodes, if a distributor wants them on cases), onto every order it ships on, and into the recall report. The ingredient lots were recorded when the stock arrived, the supplier's code or yours, and the batch notes which of them it used, so nobody copies codes from case to clipboard with sticky hands.
So the question a buyer or an inspector actually asks, "what went into this lot, and who got it?", is one report instead of a morning with the binder. Returns go back into the lot they left in, so even those are found.
Lots, expiry and recalls are on every plan, from $49 a month, and recording batches against recipes is on Standard at $99. Try it free for 30 days on your next run. If you'd like a hand setting up, ask, and we'll do it with you.