You invoice a design project to a client in Santiago and they ask for "net plus VAT." Another in Madrid sends a quote "VAT included" and you want the taxable base. In Mexico City the receipt shows subtotal plus 16%. Knowing how to calculate VAT correctly keeps you from over-quoting, undercharging, or fighting accounting at month-end.
VAT is not the same rate everywhere, and receipts do not always break it down the same way. Chile uses 19% general rate, Spain 21% on most goods and services, Mexico 16% standard. FORMARTIO helps you go from net to gross and back without manual cross-multiplication for each country.
Calculate VAT: net → total (tax included)
Formula: VAT = net × rate; total = net + VAT. Or directly: total = net × (1 + rate).
Chile 19%: net $100,000 CLP → VAT $19,000 → total $119,000. If you sell consulting for $850,000 net, VAT is $161,500 and the client pays $1,011,500 on the invoice.
Spain 21%: net €200 → VAT €42 → total €242. Online store with base €79: VAT €16.59, customer pays €95.59.
Mexico 16%: net $1,000 MXN → VAT $160 → total $1,160. A $4,500 net service adds $720 VAT; you charge $5,220.
Total with VAT → extract net (price includes tax)
Formula: net = total ÷ (1 + rate). Useful when the receipt only shows the final price.
Chile receipt $238,000 with 19% included: net ≈ $200,000, VAT $38,000. Spain: ticket €121 → net €100, VAT €21. Mexico: $580 total → net $500, VAT $80.
Step by step to calculate VAT
- Identify whether your amount is net or total with VAT included.
- Pick country and rate —19% Chile, 21% Spain, 16% Mexico in typical cases.
- Open the VAT Calculator on FORMARTIO and enter the amount.
- Select direction: add VAT or remove VAT from total.
- Note net, VAT, and total before issuing an invoice or validating a supplier receipt.
Costly mistakes
Applying 21% to a price that already included VAT and adding it again. Confusing net with total in B2B quotes: client expects €10,000 + VAT, you quoted €10,000 "all in" and lose margin.
Rounding: Chile SII e-invoices and Spanish systems round to two decimals per line. Calculating VAT with a calculator aligns expectations before closing the books.
Exempt and reduced rates
Spain has 10% and 4% on food, books, or housing depending on the case. Mexico has 0% on certain foods and medicines. Chile has sector exemptions. This article covers the general rate; confirm with an accountant if your industry is special.
Exporting services to a foreign client may have different treatment; do not copy domestic VAT to an international invoice without checking the rules.
Practical example: comparing three quotes
Same $1,000 USD-equivalent service quoted net-only in three countries: Chile charges $1,190 final, Spain €1,210 on a €1,000 base, Mexico $1,160 MXN on $1,000 net. Calculate VAT before comparing "who is cheaper" among local vendors.
Freelancer invoices 3 UF net in Chile: convert UF to pesos, apply 19%, deliver total to the corporate client that only approves payments with an explicit breakdown.
Small shop in Madrid: POS registers €1,450 per day; at close, separating 21% VAT helps reconcile cash with the output VAT ledger without mixing exempt sales.
Before closing a quote or reviewing a supplier receipt, do not guess the breakdown. Calculate VAT on FORMARTIO, confirm net and total with your country's rate, and invoice with numbers that add up.