NumberTally How the Invoice Total Is Calculated
Each line is quantity × rate, summed into a subtotal. The discount comes off first (discounts reduce the taxable amount in most places), then tax is applied to the discounted subtotal:
Line total = Qty × Rate
Subtotal = Σ lines · After discount = Subtotal × (1 − discount%)
Tax = After discount × tax% · Total due = After discount + Tax
What a Real Invoice Should Include
Beyond the line items and total: your business name and contact info, the client’s name, a unique invoice number, issue and due dates, and payment terms (e.g. “Net 30”). Number invoices sequentially — this generator does it for you in this browser — because gaps in numbering raise questions in an audit. Keep a copy of every invoice you send.
Frequently Asked Questions
How do I save my invoice as a PDF?
Click “Print / Save PDF” and choose “Save as PDF” in your browser’s print dialog. The print view is a clean invoice layout without the calculator chrome.
Is my invoice data sent to a server?
No. Everything runs in your browser; your client details, line items, and logo never leave your device.
Can I add my company logo to the invoice?
Yes — upload an image above. It’s stored locally in your browser and appears on the printed invoice.
How is the invoice total calculated?
Line totals (qty × rate) are summed, the discount is applied to the subtotal, then tax is calculated on the discounted amount. See the formula box above.
What should a real invoice include?
Business and client names, a unique sequential invoice number, issue and due dates, itemized lines, tax, the total due, and payment terms.
Can I save clients for reuse?
Yes — fill in the client name, email and address, then click “Save client”. Saved clients live only in this browser and can be picked from the dropdown on future invoices.
Can I invoice in a currency other than dollars?
Yes — pick USD, EUR, GBP, CAD, or AUD in Advanced options. Amounts are formatted for the selected currency.