Invoice + Tax Calculator
Calculate invoice totals with tax, discounts, and multiple line items.
โน๏ธAbout This Calculator
You just finished a $4,200 project, your client wants a 10% discount, and you're in a state that charges 8.25% sales tax. Quick โ what's the invoice total? It's $3,431.85, and getting that number wrong in either direction is bad. Overcharge and you look sloppy. Undercharge and you eat the difference or create a tax headache. This calculator does the math in the right order: subtotal, minus discount, then tax on the discounted amount. Works for US sales tax, UK 20% VAT, EU rates, Indonesia's 11% PPN, or any percentage you need. Plug in the numbers, get the exact total, and send the invoice before the client forgets about the project.
Frequently Asked Questions
How is tax calculated on an invoice?
Discount first, then tax. Always. A $1,000 invoice with a $50 discount and 8% tax: taxable amount is $950, tax is $76, total is $1,026. Some people accidentally tax the full $1,000 first ($80) and then subtract the discount โ that overcharges the client by $4. It's a small error that makes you look like you don't know what you're doing.
Should I charge sales tax on services?
In most US states, no โ services are generally exempt. But there's a growing list of exceptions: Hawaii, New Mexico, South Dakota, and West Virginia tax almost everything. Digital services and SaaS are getting taxed in more states every year. Physical products? Almost always taxable everywhere. When in doubt, check your state's department of revenue website โ it takes 5 minutes and beats an audit.
What is the difference between VAT and sales tax?
US sales tax only hits the final buyer. VAT (used in 160+ countries) gets collected at every stage of production, but businesses reclaim the VAT they paid on their own purchases. The end consumer pays roughly the same either way. The practical difference for you: if you're invoicing internationally, know whether your client expects VAT on the invoice โ a UK client expects to see 20% VAT itemized, not bundled into the price.
What are the major VAT and GST rates worldwide?
The ones you'll hit most often: UK 20%, Germany 19%, France 20%, Australia 10%, Canada 5% (plus provincial), Japan 10%, Singapore 9%, Indonesia 11% PPN, India 0-28% depending on the product, South Africa 15%. EU averages about 21% but ranges from 17% (Luxembourg) to 27% (Hungary). Bookmark these if you invoice internationally โ getting the rate wrong is a compliance problem.
What must be included on a professional invoice?
The non-negotiables: your business name and address, client's name and address, unique invoice number, date issued, payment due date, itemized line items with quantities and prices, subtotal, any discounts, tax rate and amount, and the total due. Add your bank details or payment link and late-payment terms ("2% monthly after 30 days" works). Missing any of these creates excuses for slow payment.
How do I handle invoices in multiple currencies?
Put the currency code (USD, EUR, GBP, IDR) right next to every amount โ no ambiguity. If you're billing in the client's currency, note the exchange rate you used and the date. For ongoing international work, pick one currency and stick with it. Wise and Stripe handle multi-currency invoicing well. Billing in USD is usually the simplest default for international freelancers.