How to calculate VAT

VAT (Value Added Tax) is the dominant consumption tax across 170+ countries — every EU member state, the UK, most of Asia, Africa, and Latin America. If you’re selling to customers outside the US, you’ll touch it. Get the math right and you stay compliant; get it wrong and you’re personally liable for the uncollected tax. This guide walks through the add-VAT and remove-VAT formulas, rates by country, B2B reverse charge rules, registration thresholds, and the four errors that trigger the most audit headaches.

What VAT is — and how it differs from US sales tax

VAT is a multi-stage tax: collected at every step in the supply chain, with each business claiming back the VAT they paid on inputs. The end consumer bears the total tax; businesses are just collectors.

Contrast with US sales tax: single-stage, collected only at final sale. US businesses don’t claim back sales tax on their inputs.

Practical implication: as a VAT-registered business, you charge VAT on sales (“output VAT”), claim back VAT on purchases (“input VAT”), and remit the difference to the tax authority. This is why VAT is called a “value-added” tax — you only remit tax on the value you added.

The two core formulas

Add VAT (you know net price, need to add VAT):

VAT amount = Net × (rate / 100)
Gross = Net + VAT amount = Net × (1 + rate / 100)

Example: £100 net at 20% UK VAT = £20 VAT = £120 gross.

Remove VAT (you know gross price, need to find net):

Net = Gross / (1 + rate / 100)
VAT amount = Gross − Net

Example: £120 gross at 20% = £100 net + £20 VAT.

Common error: people compute “remove VAT” as Gross × 0.80. That’s wrong — you’d get £96, not £100. The correct division is by 1.20.

Standard rates by country

UK: 20% standard, 5% reduced (domestic fuel, children’s car seats), 0% zero-rated (most food, children’s clothing, books).

Germany: 19% standard, 7% reduced.

France: 20% standard, 10% / 5.5% / 2.1% reduced tiers.

Ireland: 23% standard, 13.5% / 9% / 4.8% / 0% reduced.

Netherlands: 21% standard, 9% reduced.

Spain: 21% standard, 10% / 4% reduced.

Italy: 22% standard, 10% / 5% / 4% reduced.

Sweden / Denmark: 25% standard (highest in Europe).

Hungary: 27% standard (highest in the EU).

Canada: GST 5% federal + PST/HST provincial (varies). Not technically VAT but same mechanism.

Australia / New Zealand: GST 10% / 15% (VAT by another name).

Reduced and zero rates — what qualifies

Reduced rates typically apply to essentials: food, books, medicines, public transport, cultural goods. Each country sets its own list — never assume transferability.

Zero-rated ≠ exempt. Zero-rated sales are still taxable (at 0%), so you can still reclaim input VAT on related costs. Exempt sales are outside the VAT system — you can’t reclaim related input VAT. Big difference for cash flow.

B2B reverse charge — the cross-border rule

When a VAT-registered business in one EU country sells to a VAT-registered business in another EU country:

The seller charges 0% VAT (not zero-rated, but reverse-charged).

The buyer “self-accounts” — adds the VAT at their local rate on purchase, then reclaims it on the same return. Net VAT liability: zero. Just a paperwork entry.

Conditions: both parties VAT-registered, valid VAT numbers displayed on invoice, goods/services actually crossing borders. Invoice must state “Reverse charge applies — Article 196 of Council Directive 2006/112/EC” or similar.

Post-Brexit: UK → EU sales are no longer intra-EU. They’re exports (zero-rated) and the EU buyer handles import VAT on arrival.

Registration thresholds

You must register for VAT once your taxable turnover crosses a threshold:

UK: £90,000 (as of April 2024 — up from £85k).

Germany: €22,000 (small business exemption if under).

France: €85,800 (goods) / €34,400 (services).

Ireland: €75,000 (goods) / €37,500 (services).

Netherlands: €20,000 (optional small-business scheme).

EU non-residents selling B2C to EU: €10,000 combined across all EU countries triggers registration somewhere (usually OSS).

Voluntary registration below threshold is often worth it if you sell B2B (clients reclaim your VAT, so your effective price is unchanged) and have reclaimable input VAT on business costs.

Digital services and OSS

Selling digital services (SaaS, ebooks, online courses) to EU consumers: VAT is charged at the buyer’scountry rate, not yours. A UK company selling SaaS to a German consumer charges 19% German VAT, not 20% UK.

OSS (One Stop Shop): register in one EU country, file a single return covering all EU B2C digital sales. Replaces having to register in every country individually. Simplified in 2021; most SaaS businesses use it.

IOSS (Import OSS): same idea for goods imports into EU under €150.

Invoice requirements

A valid VAT invoice must include:

Your business name, address, VAT number.

Customer name, address, VAT number (for B2B).

Unique invoice number, issue date, tax point date.

Description of goods/services, quantity, unit price.

Net amount, VAT rate applied, VAT amount, gross total.

For reverse charge: explicit statement citing the directive article.

Missing any of these and your customer can’t reclaim the input VAT — they’ll chase you for a corrected invoice.

4 common VAT errors

Error 1: Wrong rate applied. Using 20% on a reduced-rate item, or 0% when you should have charged standard. HMRC/tax authority will reassess and you’ll owe the difference out of pocket (plus penalties).

Error 2: Rounding per-line instead of total.VAT should generally be calculated on the total, with a single rounding at the end. Rounding each line can create compounding errors that don’t match customer calculations.

Error 3: Missing the customer’s VAT number on B2B invoices. No valid number = you should have charged VAT. Tax authority will reassess with VAT owed by you.

Error 4: Treating reverse charge as “no VAT involved.” Reverse charge must still be reported on your return (as net sale with VAT indicator) — it just happens to net to zero. Skip the reporting and you’re filing incomplete returns.

When to get an accountant vs DIY

DIY is fine when: single country, one VAT rate, B2C only, under threshold or just over, simple products.

Get an accountant when: cross-border EU sales, mix of standard and reduced-rate products, OSS registration, partial-exemption businesses, VAT margin schemes (second-hand goods, tour operators), or when you’re being audited. The cost of getting VAT wrong exceeds the accountant fee fast — personal liability for uncollected VAT is common.

Run the numbers

Compute add-VAT or remove-VAT at any country’s rate with the VAT calculator. Pair with the invoice generator to produce a compliant VAT invoice, and the profit margin calculator to confirm margins on VAT-inclusive versus VAT-exclusive pricing.