How the Invoice Generator Works and How GST Splits Correctly
An invoice generator turns a list of goods or services into a numbered, dated billing document that a business sends to a customer to request payment. This one produces a professional PDF entirely in your browser, with a GST mode built for India that applies the correct tax split, plus multi-currency support for anyone billing international clients. Freelancers, consultants, small shop owners, and agencies use a tool like this to raise clean invoices without paying for accounting software, and because everything runs locally, no client data or bank details are ever uploaded anywhere.
The core of any invoice is the line-item math, and getting it right to the last paisa is what separates a trustworthy invoice from a sloppy one. Each line is quantity times rate, minus any discount, and tax is applied to the discounted amount. The tool keeps full floating-point precision through every line and rounds only when displaying each figure, so the subtotal minus total discount plus total tax always equals the grand total exactly. The GST split follows the CBIC rule that trips people up: when the seller and buyer are in the same state (the first two digits of their GSTINs match) the supply is intra-state and the tax is divided equally into CGST and SGST; when they are in different states it is inter-state and the whole tax becomes IGST. The tool detects this automatically from the two GSTINs and lets you override it manually for edge cases like exports.
Here is a worked example. Suppose you invoice two units of a service at 1,500 each with 18% GST, plus one item at 2,000 with a 100 discount and 12% GST, and both parties are in Maharashtra (state code 27). The subtotal is 5,000, the discount is 100, and the tax works out to 768.00, giving a grand total of 5,668.00. Because it is an intra-state supply, that 768 splits into CGST of 384 and SGST of 384. The tool prints the grand total in words too, as Rupees Five Thousand Six Hundred Sixty-Eight Only, using the Indian lakh and crore system, which banks and auditors expect on a formal invoice. Switch the same 18% line to tax-inclusive pricing and a rate of 1,180 is treated as 1,000 net plus 180 tax, so the displayed total does not change but the breakup is correct.
A freelance designer billing a client in the same state raises an intra-state GST invoice with CGST and SGST and emails the PDF the same day. An exporter or a company billing a client in another state issues an IGST invoice, and the tool switches the tax rows automatically once the buyer's GSTIN shows a different state code. A consultant working with an overseas client turns GST mode off, picks USD or EUR as the currency, and the amounts format with the correct symbol and grouping through the browser's own internationalisation engine. A small business owner uses the auto-incrementing invoice number and the duplicate-as-new button to keep a consistent sequence across dozens of invoices without a spreadsheet.
The most common invoicing mistake is applying the wrong tax type, which is why the auto-detection and the visible intra-state or inter-state label matter: charging IGST on an intra-state supply, or CGST and SGST across states, creates a mismatch that the recipient's accountant will reject. A second frequent slip is entering a tax-inclusive rate while the tool is set to tax-exclusive, which double-counts tax, so the explicit toggle keeps that honest. This tool is a document generator, not accounting software: it does not file returns, generate the official e-invoice IRN or QR code from the government portal, or validate a GSTIN against the live database beyond a format check, so verify the final figures with your CA before sending. Every calculation and the PDF itself are produced locally in your browser, so your invoice details, client information, logo, and bank details never leave your device.
