The description and the HSN or SAC sit next to each other on every invoice line, get filled in fast, and are the two fields most likely to be regretted six months later. Here is what each is doing.
Description: write what you sold, not what you call it
"Pipe" is not a description. "Steel pipe 25mm" is. The test is whether someone who was not there — your accountant, your customer's accounts team, you next March — could tell what was supplied. Internal shorthand fails that test, and shorthand is what everyone types when in a hurry.
Why a vague description costs you specifically
- A customer dispute becomes your word against theirs, with nothing on the document to settle it.
- You cannot tell what actually sells, because forty variations of "item" do not group.
- Anyone reviewing your books has to ask you, which means the question comes at the worst time.
HSN and SAC: the code, not a category
HSN for goods, SAC for services. It is a classification code, not a free-text label, and it is the thing that lets a return be filed from your invoices without someone re-deciding each line. Which code applies to what you sell is a question with a right answer — and it is not one your billing software should be inventing for you.
Where the code comes from
The GST portal, or your accountant. Look it up once for each thing you sell and put it on the item record, not on the invoice — then it is right on every future line automatically. Software that guesses an HSN for you is doing you no favours; a wrong code that appears consistently is harder to spot than a blank one.
Put it on the item, not the invoice
This is the whole trick. Description, HSN and rate all belong to the thing you sell, set once. If they are being typed per invoice, they will drift — the same product will appear under three descriptions and two codes within a year, and none of the reporting will group correctly.
A quick audit you can do today
Open your last twenty invoices and read only the description column. If you cannot tell what was supplied on more than one or two lines, the fix is not more discipline at billing time — it is an item master with the descriptions written properly once.
Deliberately not in this article
Any specific HSN code, any rate, and any threshold for when HSN digits are required. Those come from the GST portal or your CA, with the source recorded. Everything above is about record quality, which is the same whatever the rules say.