Invoice Generator
Create invoices with automatic amount, GST, discount, and total calculation.
Written by Anil Gautam · Updated
How does the invoice work out GST after a discount?
Each line amount is quantity times rate, and its GST is that amount times the percentage you enter. There is no built-in rate table; new lines start at 18 percent. Subtotal is the sum of line amounts before tax. A discount is a flat amount, capped at the subtotal, and the tool cuts the total GST in the same proportion as the discount cuts the subtotal. CGST + SGST mode splits that GST into two equal halves, IGST mode shows it as one figure, and No tax removes it.
With the default line, 1 unit of website service at ₹5,000 with 18 percent GST, and a discount of ₹500, the taxable value is ₹4,500. GST falls from ₹900 to ₹810 (900 times 4,500 divided by 5,000), shown as CGST ₹405 and SGST ₹405, and the total is ₹5,310. The Amount column for the line still reads ₹5,900, because line amounts include GST before the discount, so that column will not add up to the total once a discount applies.
For a sale within one state the tax is normally shown as CGST plus SGST, and for a sale between states as IGST. Before a GSTIN goes on the invoice, check it with the GSTIN Validator, which also names the state from its first two digits.
What does the downloaded PDF contain?
The PDF is an A4 document built in your browser. It carries the title Invoice in your accent color, the invoice number, date and optional due date, a From block with your details and a Bill To block with the client's. The item table lists each line's name with its HSN/SAC code underneath, quantity, rate, GST percentage and line total, followed by Subtotal, Discount when there is one, CGST and SGST or IGST, Grand Total and your notes. Its file name comes from the invoice number, so INV-0001 downloads as INV-0001.pdf.
Amounts in the PDF have two decimals and no thousands separators. The prefix follows the Currency menu: Rs. for rupees, $ for US dollars, £ for pounds and EUR for euros, because the PDF's built-in font has no ₹ sign and cannot print €. Keep item names short, because each PDF row has a fixed height and a name that wraps onto a second line runs into the HSN/SAC line below it. The PDF has no amount-in-words line, so if you need one, add it to Notes; the Number to Words Converter writes amounts in lakh and crore style.
What should you check before sending the invoice?
The invoice number does not count up by itself, so change INV-0001 for each new invoice. Nothing you type is saved, and reloading the page clears every field, so download the PDF before you close the tab. If you agreed a GST-inclusive price with a client, the GST Calculator splits it into the base amount and tax so you can enter the base as the rate.