Your client’s accounts team doesn’t reject invoices because they enjoy it. They reject them because a missing field breaks their GST return and their CA yells at them. Then they yell at you. Then you don’t get paid on time.
Here’s what a proper GST tax invoice needs under Rule 46 of the CGST Rules:
- Your legal name and address — as registered on your GST certificate
- Your GSTIN — 15 characters, no typos (seriously, copy-paste it)
- Invoice number — unique, consecutive per financial year
- Invoice date — the date of issue, not when you finished the work
- Client name and address — registered business name for B2B
- Client GSTIN — mandatory for B2B; without it, no ITC for them
- HSN or SAC code — per line item (services = SAC, goods = HSN)
- Description of goods/services — clear enough that accounts knows what they’re paying for
- Quantity and unit — hours, pieces, months — whatever applies
- Taxable value — amount before GST, per line and total
- GST rate and amount — CGST+SGST or IGST, with amounts split correctly
- Total invoice value — taxable + tax, in numbers and words (Indian numbering: lakh/crore)
Bonus fields that speed up payment
Not legally required, but they help you get paid faster:
- Place of supply — state name, especially for inter-state invoices
- Payment terms & due date — “Net 15” or “Due on receipt”
- UPI ID and payment link — on the PDF, not buried in email
- Your bank details — for clients who pay via NEFT/RTGS
Common rejection reasons
- Wrong GST split (IGST instead of CGST+SGST for same-state client)
- Missing or wrong SAC code
- Invoice number out of sequence
- Taxable value doesn’t match line items (rounding errors)
- Amount in words missing or wrong
Let the tool handle the boring parts
BillFast fills in GST split from state codes, calculates tax per line, writes amount in words, and adds a Pay Now block with UPI + Razorpay. You focus on the work. The invoice focuses on getting you paid.