I once sent identical invoices to two clients, same amount, same work, and one owed tax while the other legally owed zero. Same service, different customer paperwork. That pair of invoices is the whole B2B-versus-B2C story: the math follows the customer type, not the work performed.
The framework: B2C (end consumers) pay the full combined rate at their destination, nearly always. B2B resale, a retailer buying your goods to resell, is $0 tax with a valid resale certificate on file; you note the cert ID on the invoice and move on. B2B end-users buying for their own use pay just like consumers unless a specific exemption applies. Nonprofits and government buyers are $0 with a valid exemption letter, which is a different document from a resale cert and must match the purchasing entity.
The failure mode I see constantly: businesses extending B2B courtesy exemptions on vibes. “They’re a business, so no tax” is wrong, a business buying office supplies for itself owes tax like anyone else. Only the certificate decides, and certificates expire, get revoked, or cover the wrong state. I re-verify certs annually for repeat B2B clients; it takes minutes and it’s the difference between a clean audit and a reassessment.
On the invoice itself, $0-tax lines should still show their work: “Sales Tax (resale cert #TX-XXXX): $0.00”. Silence looks like omission; annotation proves compliance.
Takeaway: consumer pays, documented resale/exempt pays zero, undocumented business pays, paperwork decides everything.
Try it live: Invoice Tax Breakdown Calculator, run your own numbers in seconds.
How do you use Invoice Tax Breakdown Calculator?
Open the Invoice Tax Breakdown Calculator in your browser (Split any invoice into subtotal, tax, and total, per line item). Type or paste your input, adjust the options, and copy the result. Everything runs locally on your device with no account and nothing stored, so the three steps below take seconds even for confidential work.
- Enter your numbers into the fields. The result recalculates as you type.
- Switch any unit or option to see the updated answer instantly.
- Copy the result with the copy button, or read the summary beneath it.
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