What a tax invoice has to show
A tax invoice is an ordinary invoice that also breaks the tax out so the reader can see it separately from the price of the work. That separation is the whole point. If tax is buried inside a single figure, the person paying you cannot tell how much of it they may be able to reclaim, and a bookkeeper cannot post it to the right account without reverse-engineering your number. So the practical requirement in most places is simple: state the tax rate, state the amount of tax, and state it as its own line under the subtotal. This tool does exactly that. You type a rate, it computes the tax on the base, and it prints a named line - VAT, GST, sales tax, or whatever you write in the tax label field.
Most tax regimes also want to know who issued the document, which is why you see a registration number on real tax invoices: a VAT number in much of Europe and the UK, an ABN in Australia, a GSTIN in India, a GST/HST number in Canada, and similar identifiers elsewhere. The registration number field here prints whatever you type. It is a place to put your number, not a decision about whether you are required to have one, because that turns on whether you are registered and where.
Everything else on a tax invoice is the same as on any invoice a client can pay from: a unique number, the issue date, a due date or payment terms, who is billing, who is being billed, a description of what you supplied, and the amount with its currency. If the document is missing those, it is not a usable invoice no matter how the tax line reads.
How this tool calculates tax
The order matters, so it is worth stating plainly. The tool totals your line items into a subtotal, takes off any discount, and then applies your tax rate to what is left. Discount first, tax after. If a discount came off after tax, or tax were charged on the full pre-discount amount, the printed tax would disagree with what you actually collect, and that is the sort of inconsistency that gets an invoice queried. A quick example: a subtotal of 1,000 with a 10 percent discount gives a taxable base of 900, and at an 18 percent rate the tax line reads 162, not 180.
One limit to understand: the tool applies a single rate you set to the whole discounted subtotal. It has no concept of a line that is taxable and a line that is exempt, or of two different rates on one document. If you need to mix a standard-rate item with a reduced-rate or zero-rated item, the honest options are to split them across separate invoices, or to do the split arithmetic yourself and enter a rate that reproduces the correct tax figure for this particular invoice.
Shipping and other charges are handled as a separate input. Tax is computed on the discounted subtotal, and shipping can be brought into that base if that is what you want; otherwise it joins the total after tax, unchanged. The result is floored at zero, so a large discount cannot produce a negative invoice. Money is kept as whole minor units internally, so the figures you see in the preview are the figures the PDF prints, with no rounding drift.
What the tool does not decide for you
Be clear about the boundary. This generator computes and prints the tax line, and it prints the registration number you type. It does not know your country's mandatory wording, it does not file a return, and it does not connect to any tax system. The jurisdiction select is a labeling aid, not a rules engine: it changes the hint on the registration field so it matches the identifier that country commonly uses, and that is all. It does not switch on a rate, and it does not know whether you are registered.
The registration examples shown in the table below are format illustrations drawn from what each country's identifier commonly looks like, taken from the placeholder examples on this very page. They are not legal requirements and they are not a checklist. Whether you must print a number, what format is accepted, and what wording makes the document a valid tax invoice all vary by country and by your registration status, and they change over time. Confirm the specific requirement with your own tax authority or an accountant before you rely on a generated document.
The same caution applies to the rate itself. The tool never fills the rate for you, because a correct rate depends on the country, the type of supply, and sometimes the buyer. You enter it. If you are unsure which rate applies to a given sale, that is a question for the authority or your accountant, not something a form on a website should answer.
| Jurisdiction select | Tax type it names | Registration field example | Commonly required? |
|---|---|---|---|
| United States | Sales tax | EIN / SSN (optional) | Only if you collect sales tax; varies by state |
| United Kingdom | VAT | VAT number like GB123456789 | On a VAT invoice once you are registered |
| EU country (OSS) | VAT | VAT number like DE123456789 | Varies by member state and scheme |
| Australia | GST | ABN, 11 digits | On a tax invoice when registered for GST |
| New Zealand | GST | GST number | On a tax invoice when registered |
| India | GST | GSTIN, 15 characters | Where a tax invoice is required |
| Canada | GST/HST | GST/HST number, 15 characters | When registered |
| Singapore | GST | GST registration number | When registered |
Tax invoice, proforma, and receipt are not the same
These three documents get used interchangeably and they should not be. A tax invoice requests payment and shows tax separately; in many countries it is also the document your business customer needs in order to reclaim that tax, which is why the separate tax line and your registration number matter so much on it. Issue a tax invoice when you are billing for work you have done or are contractually due to bill for.
A proforma is a good-faith estimate of what an invoice will look like, often sent before work or before goods ship so a buyer can arrange payment or clear customs. It is generally not the document that triggers a tax point, and it is not a demand you post to your ledger the same way. A receipt is the opposite end of the transaction: it confirms money has already been received. The tool does not have a proforma switch, so if you want a proforma, label the notes line to say so and treat it as a quote. To turn a document into something that reads like a receipt, set already-paid to the full total so the balance prints as zero and note that the amount was received.
The practical upshot: use a tax invoice to bill tax separately, use the notes line to make clear when you are sending an estimate rather than a bill, and use the paid field when the money is already in hand so the printed balance is honest.
Reverse charge, and when to leave it off
Reverse charge is a mechanism, seen most often on cross-border business-to-business sales inside the EU, where the buyer accounts for the tax instead of the seller charging it. When it applies, the seller's invoice typically shows no tax amount and instead carries a note pointing out that the recipient accounts for the tax. This tool can print that note for you through the reverse-charge option, and when you switch it on you would normally leave the tax rate at zero so no tax amount appears.
It is a wording aid, not advice, and it is easy to apply wrongly. Whether a sale falls under reverse charge depends on both parties being registered, on the type of supply, and on the countries involved. Switching the note on does not make a transaction a reverse-charge sale; it only prints the words. If you are not certain the rule covers a given sale, leave the option off and get the position confirmed for that specific deal rather than assuming the note makes it correct.
Invoice numbering that tax authorities actually check
Plenty of invoicing advice treats the invoice number as cosmetic. Under tax regimes it is usually not. The common expectation is that numbers are sequential, unique, and free of gaps, so that a series of invoices can be followed in order and nothing appears or disappears quietly. That is the requirement this tool helps you meet without thinking about it: when you save a draft, the numbers you have used are kept in your browser, and the next invoice is generated from the same pattern with the sequence stepped forward, so INV-2026-09-014 becomes INV-2026-09-015. The pattern supports a four- or two-digit year, a month, and a zero-padded sequence, so you can match whatever series your bookkeeping already runs.
Two honest cautions. First, nothing syncs between devices - local storage lives in one browser on one machine - so if you invoice from a laptop and a desktop, keep one of them authoritative for numbering, or set the number by hand. Second, do not delete issued invoices out of a sequence to tidy things up; a missing number raises exactly the question you do not want to answer during an inquiry. If an invoice was wrong, issue a corrected one that references the old number rather than silently removing the gap.
A quick test you can run yourself: print or save a handful of invoices and check that every number is different and that they climb in order with no skips. Accounts-payable teams and tax reviewers look for the same thing, and a duplicate number is one of the most common reasons a payment simply gets held until you reissue.