# Invoice format in India: what an invoice must show, how discount and GST are worked out, and how to make a PDF for free

> The parts of a proper invoice, how a ₹21,000 job becomes ₹24,780 with 18 percent GST (and ₹22,302 after a 10 percent discount), what a simple invoice maker can and cannot do for a GST-registered business, and the habits that get freelancers paid on time.

Published 2026-10-23 by Toolcloak. 5 minute read. Original: https://toolcloak.com/articles/invoice-format-in-india-what-a-gst-invoice-must-show-how-tax-and-discount-are-worked-out-and-how-to-make-a-pdf
Related free tool: [Invoice Generator](https://toolcloak.com/tools/invoice-generator)

You finish the work. Now you need a document that says what you did, how much it costs and when to pay. A vague message with a number in it gets you a vague reply. A clean invoice, with a number, a date, line items and the tax worked out, gets you a payment and, later, a record your accountant is happy to see. This guide covers what goes on it, how the maths works, and what a simple tool can and cannot do.

> **In short**
> - **An invoice needs:** who is billing, who is being billed, a unique number, a date, line items with quantity and price, tax, the total and how to pay.
> - **Order of maths:** subtotal, then discount, then tax on the discounted amount, then total. ₹21,000 at 18% GST is ₹24,780.
> - **A GST-registered seller must show more:** GSTIN, HSN or SAC codes, and the CGST and SGST (or IGST) split.
> - **Send it as a PDF,** with a due date and payment details, and keep a copy.

## What goes on an invoice

**The four zones of a good invoice**

| Box | What it means |
| --- | --- |
| Top: who and when | Your name and address, the word INVOICE, a unique invoice number, the date and the due date. |
| Bill to | The client’s name and address. For business clients, their GSTIN too, if they are registered. |
| Middle: the items | A description, quantity, price and amount for each line. Keep descriptions clear enough to understand a year later. |
| Bottom: the money | Subtotal, discount, tax, total, and payment details such as UPI ID or bank account and terms. |

*Put the total and the due date where the eye lands first. That is what the client looks for.*

Try it: [Invoice Generator](https://toolcloak.com/tools/invoice-generator). Enter your details, the client, items (description, quantity, price), discount and tax, then print or save as a PDF.

In the builder, each item goes on its own line as **description | quantity | price**. A tax percentage and a discount percentage apply to the whole invoice, and the totals are written in Indian number style with two decimals. You also choose a currency symbol, an accent colour and a notes box for payment details.

## The maths: discount first, then tax

The default sample is a small web job: website design ₹15,000, hosting for a year ₹3,000 and two logos at ₹1,500 each, with 18 percent GST.

**No discount: from subtotal to total (₹)**

| Step | Amount |
| --- | --- |
| Subtotal | ₹21,000 |
| GST 18% | +₹3,780 |
| Total | ₹24,780 |

*₹15,000 + ₹3,000 + (2 × ₹1,500) = ₹21,000. GST = 18% × ₹21,000 = ₹3,780.*

**With a 10% discount (₹)**

| Step | Amount |
| --- | --- |
| Subtotal | ₹21,000 |
| Discount 10% | −₹2,100 |
| Taxable value | ₹18,900 |
| GST 18% | +₹3,402 |
| Total | ₹22,302 |

*The discount comes off first, and GST is charged on what is left. That is how the tool works and how a tax invoice normally treats a discount that is shown on the invoice.*

> **Two common mix-ups:** Adding the discount after tax gives a different total (₹24,780 − ₹2,100 = ₹22,680, not ₹22,302). And if the price you quote already includes GST, work backwards instead. See [how to add or remove GST without getting it wrong](https://toolcloak.com/articles/how-to-add-or-remove-gst-without-getting-it-wrong). The [discount stacking guide](https://toolcloak.com/articles/50-percent-off-plus-20-percent-off-is-not-70-percent-off) explains why percentages do not simply add up.

## Invoice number and date

- **Make the number unique and in sequence,** such as INV-001, INV-002. Many businesses add the financial year, like INV/2026-27/001.
- **Never reuse a number.** If you need to fix an invoice, issue a credit note or a corrected one with a new number, and keep the old one on record.
- **Use a full date** such as 23 Oct 2026, and set a due date. “Payment within 7 days” in the notes is good, but a calendar date is clearer.
- **Do not skip numbers.** A gap makes an accountant ask why.

## If you are registered for GST

A business registered under GST has to issue a **tax invoice** with more detail than the simple version. The exact list depends on the kind of supply and the turnover, so confirm it with an accountant, but in general a tax invoice shows:

| Needed on a GST tax invoice | Does the invoice tool cover it? |
| --- | --- |
| Seller’s name, address and GSTIN | You can type them in your address box |
| Unique invoice number and date | Yes |
| Buyer’s name, address, and GSTIN for business buyers | Name and address yes; add the GSTIN in the client address box |
| HSN or SAC code for each item | Type it in the description, such as “Web design (SAC 998314)” |
| Taxable value after discount | Shown as the amount before tax |
| CGST and SGST, or IGST, with rates and amounts | One tax line only. Write “CGST 9% + SGST 9%” in the notes |
| Place of supply for inter-state sales | Add in notes |
| Signature or digital signature | Add a [signature image](/articles/how-to-make-a-digital-signature-png-with-transparent-background-draw-or-type-and-use-it-on-forms-and-pdfs) to the PDF |

*The tool is a simple invoice maker with one tax percentage. It gives you the right totals, but it is not a GST billing system. If you issue many GST invoices, use accounting software.*

> **Not registered? Do not charge GST:** If you are not registered for GST, you cannot collect it from clients. Set tax to 0 and issue a simple invoice or bill. Charging tax you are not entitled to collect creates a problem for you and the client.

## Payment details and terms

**From invoice to payment**

1. **Add how to pay.** UPI ID, bank account with IFSC, or a payment link in the notes.
2. **Make payment easy.** A [UPI QR code](https://toolcloak.com/articles/how-to-create-a-upi-qr-code-for-your-shop-or-payments-fixed-amount-or-any-amount-and-how-to-test-it-safely) with the invoice amount saves a typing mistake.
3. **Write the amount in words.** Helpful for larger sums. See the [numbers in words guide](https://toolcloak.com/articles/how-to-write-numbers-in-words-for-cheques-and-invoices-lakh-and-crore-against-million-and-billion).
4. **Send and follow up.** Send the PDF by email or [WhatsApp](https://toolcloak.com/articles/how-to-make-a-whatsapp-link-that-opens-a-chat-with-a-ready-message-no-need-to-save-the-number), then a polite reminder on the due date.

*Faster, simpler payment methods mean faster payment.*

## Pricing sense for freelancers and small shops

- **Quote the rate that covers your costs.** The [freelance rate guide](https://toolcloak.com/articles/freelance-rate-calculator-how-to-set-an-hourly-rate-that-covers-tax-expenses-and-time-off) shows how to work it out.
- **Know your margin,** not just your price. See the [profit margin guide](https://toolcloak.com/articles/profit-margin-calculator-how-to-work-out-margin-profit-and-markup-and-set-a-price-for-a-target-margin).
- **Show hours or units** if the client may question the price.
- **Add a late-payment line** such as “interest at 1.5% per month after the due date” only if you are prepared to apply it.

## Saving and sending the PDF

1. Fill in the form and check the preview. Totals update from your items.
2. Click Print / Save as PDF and choose Save as PDF in the printer list.
3. Name the file with the number and client, like INV-2026-27-001-Sharma.pdf.
4. Keep the PDF in a folder, sorted by financial year, and a note of when it was paid.
5. If you must shrink the file, see the [PDF compression guide](https://toolcloak.com/articles/how-to-compress-a-pdf-why-files-are-so-big-and-how-to-get-under-an-upload-limit). For receipts that tenants and landlords use, see the [rent receipt guide](https://toolcloak.com/articles/rent-receipt-for-hra-what-to-write-when-the-landlord-pan-is-needed-and-how-to-make-12-monthly-receipts).

Related guides: [how to make a salary slip](https://toolcloak.com/articles/salary-slip-format-in-india-what-a-payslip-must-show-how-net-pay-is-worked-out-and-how-to-make-a-pdf-for-free).

## Frequently asked questions

### What should an invoice include?

The seller’s name and address, the buyer’s name and address, a unique invoice number, the date, a description with quantity and price for each item, any tax, the total, and payment details. A GST-registered seller must add more, including GSTIN and tax split.

### Invoice kaise banaye?

Invoice generator me apna aur client ka naam-pata, invoice number, date, items (description | quantity | price), tax aur discount bharein, preview dekhein aur Print / Save as PDF se PDF bana lein.

### How is GST calculated on an invoice with a discount?

Subtract the discount from the subtotal first, then apply GST to the discounted amount. For ₹21,000 with 10 percent discount and 18 percent GST, the taxable value is ₹18,900, GST is ₹3,402 and the total is ₹22,302.

### Can I make a GST invoice with this tool?

It handles the totals with one tax percentage and lets you type GSTIN, HSN and tax split into the text boxes, but it does not create the CGST and SGST columns. For regular GST billing, use accounting software.

### How do I number invoices?

Use a unique, running sequence such as INV-001, INV-002, often with the financial year added. Never reuse a number, and issue a corrected invoice or credit note instead of editing a sent one.

### Do freelancers need to charge GST?

Only if they are registered for GST. If you are not registered, you cannot charge it. Registration depends on turnover and the type of work, so check with an accountant.

### What is the difference between an invoice and a receipt?

An invoice asks for payment. A receipt confirms that payment was received. Many businesses issue both.

### Is it safe to make an invoice online for free?

It is safest in a tool that runs in your browser and does not upload your client details. Keep a copy of every invoice you send.