GST Invoice Mandatory Fields: Complete Checklist India 2025

Under the CGST Act 2017 and Invoice Rules, a GST invoice must contain specific mandatory fields. If any required field is missing, the invoice is non-compliant — and your buyer cannot claim Input Tax Credit (ITC) on it.

Mandatory GST Invoice Fields (Complete Checklist)

#	Field	Example	B2C Mandatory?
1	Invoice serial number (unique in FY)	INV-2025-001	Yes
2	Invoice date	01/04/2025	Yes
3	Supplier name and address	Acme Tech, 123 MG Road, Mumbai	Yes
4	Supplier GSTIN	27AABCU9603R1ZX	Yes
5	Supplier state	Maharashtra	Yes
6	Recipient name and address	Client Corp, Bangalore	Yes
7	Recipient GSTIN	29AAACR5055K1ZB	B2B only
8	Place of supply (state)	Karnataka	Yes
9	Description of goods/services	Software Development Services	Yes
10	SAC code (services) / HSN code (goods)	998313	If turnover >₹5Cr: mandatory. Below: optional
11	Quantity and unit (for goods)	N/A for pure services	For goods only
12	Unit price / rate	₹1,00,000	Yes
13	Taxable value (before GST)	₹1,00,000	Yes
14	GST rate (CGST/SGST or IGST)	IGST 18%	Yes
15	GST amount (CGST/SGST or IGST)	IGST ₹18,000	Yes
16	Total invoice value (with GST)	₹1,18,000	Yes
17	Whether supply is interstate or intrastate	Interstate	Yes
18	Supplier's authorised signature	[Signature]	Yes

Common Invoice Mistakes That Invalidate ITC

• ❌ Wrong GSTIN of supplier or recipient
• ❌ Charging CGST+SGST for interstate transaction (should be IGST)
• ❌ No mention of HSN/SAC code (if applicable)
• ❌ Invoice number not unique within the financial year
• ❌ Missing place of supply
• ❌ Incorrect tax computation

Relaxations for Small Businesses

• If annual turnover is below ₹5 crore: HSN/SAC code at 4-digit level required
• If annual turnover is below ₹1.5 crore: HSN/SAC not mandatory
• B2C invoices (to unregistered persons) have relaxed field requirements — no GSTIN field needed