About the GST Billing Calculator
What is the GST Billing Calculator?
This calculator prepares the numbers for a single-item GST invoice. It applies the trade discount, adds freight charged on the invoice to the taxable value, and splits the tax into CGST and SGST for sales within your state or IGST for sales to another state.
The total is rounded to the nearest rupee, with the round-off shown separately as on a printed invoice.
How to use the GST Billing Calculator
- Quantity (sample: 10)
- Rate per Unit (₹, before GST) (sample: 1,250)
- Trade Discount (%) (sample: 5)
- Freight / Packing Charged on the Invoice (₹) (sample: 500)
- GST Rate (sample: 18%)
- Place of Supply (sample: Same state (CGST + SGST))
- Press Calculate Invoice with GST (results also refresh as you type). The result card shows the Invoice Total, along with Taxable value, Discount, CGST (9%) and SGST (9%).
Formula used
Invoice total = Taxable value × (1 + GST rate), rounded
- Taxable value = quantity × rate − discount + freight and packing charged
- Intra-state = CGST and SGST each at half the rate
- Inter-state = IGST at the full rate
GST rates after 22 September 2025 are 5%, 18% and 40% for most goods, with 0% for exempt items.
Worked example
These are the sample values already filled in the calculator above, and the result it returns for them:
| Input | Sample value |
|---|---|
| Quantity | 10 |
| Rate per Unit (₹, before GST) | 1,250 |
| Trade Discount (%) | 5 |
| Freight / Packing Charged on the Invoice (₹) | 500 |
| GST Rate | 18% |
| Place of Supply | Same state (CGST + SGST) |
| Result | Value |
|---|---|
| Invoice Total | ₹14,603 |
| Taxable value | ₹12,375 |
| Discount | ₹625 |
| CGST (9%) | ₹1,114 |
| SGST (9%) | ₹1,114 |
| Round-off | ₹0.5 |
Tips for using the GST Billing Calculator
- Discounts shown on the invoice at the time of supply reduce the taxable value.
- Place of supply, not the seller's location alone, decides CGST+SGST vs IGST.
- For several items, use the multi-item GST bill builder.