CGST, SGST, IGST — explained for glass shops

If you've ever wondered why some invoices show CGST and SGST while others show only IGST, you're not alone. Here's the simple version.

The basic rule

India has two layers of GST:

• Central GST (CGST) — goes to the central government
• State GST (SGST) — goes to the state government

When you sell to a customer in your own state, the tax splits in half: CGST + SGST.

When you sell to a customer in a different state, it's a single tax called IGST (Integrated GST). The full rate, one line, the central government distributes the state's share later.

Example with real numbers

Say you're a glass shop in Pune (Maharashtra) and your tax rate is 18%.

Customer A is in Mumbai (Maharashtra — same state):

• Subtotal: ₹1,00,000
• CGST 9%: ₹9,000
• SGST 9%: ₹9,000
• Total: ₹1,18,000

Customer B is in Ahmedabad (Gujarat — different state):

• Subtotal: ₹1,00,000
• IGST 18%: ₹18,000
• Total: ₹1,18,000

Same total, but the structure is different. If you put CGST/SGST on a Gujarat customer's invoice (or IGST on a Maharashtra customer's), it's a compliance issue.

How GlassBuddy handles this

GlassBuddy detects the customer's state from their GSTIN automatically (the first 2 digits of any GSTIN are the state code). When you create a quote, GlassBuddy looks at:

• Your business state (from your company profile)
• The customer's state (from their GSTIN)

If they match, you get CGST + SGST. If they differ, you get IGST. Done. You never have to think about it.

What if the customer doesn't have a GSTIN?

For an unregistered customer (B2C), the same intra/inter-state rule applies based on their address. In GlassBuddy, just pick their state from the dropdown when adding them. The tax math takes care of itself.

What about HSN codes?

For now, GlassBuddy handles overall GST math. HSN-wise breakup is coming as part of the GST Reports module, useful for GSTR-1 filing.