Invoice Generator

The Invoice Generator builds a print-ready PDF entirely in your browser using the pdf-lib library, so your client details and line items are never uploaded to a server. When you click Download PDF it creates a single A4 page (595 x 842 points), embeds the Helvetica and Helvetica-Bold standard fonts, and lays out a fixed template: a bold "INVOICE" header with the invoice number top-right, a From block on the left, a Bill To block and the invoice/due dates on the right, a line-item table (Description, Qty, Unit Price, Amount), a totals box, optional notes, and a centered "Thank you for your business!" footer. The form captures most fields a basic invoice needs - a unique invoice number, issue date, due date, your name/address/email, the client's name/address/email, itemized lines, and a notes area (whose placeholder suggests payment terms) - but it has no dedicated field for a tax/VAT registration ID, so if your jurisdiction requires one you must add it manually inside the From address or Notes text.

The arithmetic is deliberately simple and worth understanding because the order matters. Each line's amount is quantity x unit price; the subtotal sums those lines. Tax is computed as subtotal x (taxRate / 100) using a single flat rate, so there is no support for multiple tax bands or per-line tax. Importantly, Discount is entered as a flat currency amount rather than a percentage, and the final total is calculated as subtotal + tax - discount - meaning the discount is subtracted AFTER tax is added on the full subtotal, not before. A 10% tax on a $100 subtotal with a $5 discount therefore yields $105, not a discounted-then-taxed figure. The tax and discount rows only appear in both the preview and the PDF when their values are greater than zero.

Defaults and conveniences are built in: the invoice number is pre-filled as INV- followed by a base-36 timestamp, the invoice date defaults to today, and the due date defaults to 30 days out. Eight currencies are offered (USD, EUR, GBP, JPY, CAD, AUD, CHF, INR) and amounts are formatted simply as the currency symbol plus a two-decimal value (for example $1234.50) - there is no locale-aware thousands grouping, and even JPY is shown with two decimals. A live Preview toggle renders the same layout on screen before you commit, every invoice must keep at least one line item (removing the last is blocked with an error toast), and a Share button encodes only the currency and default tax rate into a URL. Because everything is client-side there is no saved invoice history or recurring-billing ledger, so download and archive each PDF (named invoice-<number>.pdf) yourself.