A sales tax invoice isn't just a bill — it's a legal document. If it's missing a required field, your buyer can lose the right to claim input tax on it, and you risk problems in an audit. So it pays to know exactly what a valid GST (sales tax) invoice must show in Pakistan.
Who must issue a sales tax invoice?
Any person registered for sales tax must issue a serially numbered tax invoice for each taxable supply. The invoice is what allows the buyer (if registered) to claim the sales tax back as input tax — which is why customers care that yours is correct.
The fields a valid sales tax invoice must show
Under Pakistan's Sales Tax Act, a tax invoice generally must include:
- Supplier's name, address and sales tax registration number (STRN).
- Buyer's name, address and registration number.
- A unique, sequential serial number.
- Date of issue.
- Description and quantity of the goods or services.
- Value excluding sales tax.
- The amount of sales tax charged.
- Value including sales tax.
Extra fields under FBR digital invoicing
If your business falls under FBR's digital invoicing mandate, each invoice must also carry:
- A unique Invoice Reference Number (IRN) issued by FBR.
- A valid FBR QR code that customers can verify.
- A digital signature.
Common mistakes that cause trouble
- A missing or wrong STRN/NTN.
- Invoice numbers that aren't unique or sequential.
- The wrong sales tax rate for the item.
- Leaving off the buyer's registration number on B2B sales.
- Not retaining invoice records (they must be kept for six years).
Why it matters
Your customer's input tax adjustment depends on a valid invoice, so errors cost you goodwill and repeat business. And under digital invoicing, an e-invoice can only be corrected within 72 hours through FBR — after that you need Commissioner approval. Getting it right the first time is far easier than fixing it later.
How AmalERP keeps invoices compliant
AmalERP generates sales tax invoices with every required field — auto-numbered, with your STRN/NTN, buyer details and correct tax. And because AmalERP is built by a certified FBR digital invoicing integrator with direct PRAL API access, invoices for businesses under the mandate carry the IRN, FBR QR code and digital signature automatically.