Cross-border Tax Estimator

Formula and Parameters

We use two simple formulas depending on whether the input price is tax-inclusive or exclusive:

Tax-Exclusive (US-style sales tax)

tax = amount × (rate / 100)
total = amount + tax

Tax-Inclusive (EU-style VAT / Brazil ICMS)

subtotal = amount / (1 + rate / 100)
tax = amount − subtotal

Where

Symbol	Meaning
amount	User-entered value (either gross or net)
rate	Tax rate in percent (e.g. 20 for 20%)
subtotal	Net amount before tax
tax	Tax portion of the total
total	Gross amount including tax

Default Rates by Jurisdiction

Real-World Cross-Border Tax Scenarios

Three common situations where this estimator saves time — and costly mistakes.

Spoiler: You're selling digital products to the US from Germany

You run a small SaaS in Berlin pricing subscriptions at €29/month (VAT-inclusive). A customer in California pays $31. Your payment processor converts and deposits $30.20 to your German account. Here's what the tax picture actually looks like:

• EU side: €29 is already 19% German VAT (≈€4.63). Since your customer is outside the EU, you should have charged 0% VAT (reverse charge). That €4.63 was over-collected and must be refunded or declared.
• US side: California assesses 7.25% sales tax on the USD amount, not the EUR amount. $31 × 7.25% = $2.25 tax. Because your company is in Germany, you owe this as a foreign seller's tax obligation to California's CDTFA — not to the IRS.
• Platform fee trap: If Stripe or Paddle collected $31 from the customer and processed $30.20, the $0.80 difference is Stripe's fee. But US sales tax is calculated on the customer-charged amount ($31), not the net you receive.

Run it through this tool: enter $31, select US Sales Tax, rate 7.25%, exclusive. You'll get $2.25 tax and $33.25 total — the correct figure for your US filing.

Scenario 2: A Brazilian freelancer invoicing an EU client

You're a developer in São Paulo. A Dutch company hires you for a €4,000 project. The Dutch client asks for an invoice with "EU VAT charged" — but you're in Brazil, not the EU. What applies?

• Brazilian ICMS: Service exports from Brazil are ICMS-exempt under the Lei Kandir provisions — provided your client pays in foreign currency and you have an export registration (Rex). So 0% ICMS.
• EU VAT: Since you're not established in the EU, the reverse charge mechanism applies — your Dutch client self-charges 21% Dutch VAT on your invoice amount and deducts it immediately. You never charge or collect EU VAT.
• Practical import: Your invoice should show €4,000 with no tax line but a note: "Reverse-charge VAT applies in the recipient's EU member state under Article 196 of the EU VAT Directive."

Scenario 3: Dropshipping from a third country to EU and US

You dropship physical goods from China to customers worldwide. Your supplier charges you $5 per item, and you sell for $19.99 + shipping. Two different tax worlds collide:

EU — Import VAT under €150 threshold

The EU abolished the €22 tax-free import threshold in 2021. All shipments from outside the EU now face import VAT at the destination country's rate. For a €15 item sent to Germany:

• Customs value: €15 + €2 shipping = €17 (declared value)
• German import VAT: €17 × 19% = €3.23
• Small consignment threshold: €150 — below this, a simplified IOSS (Import One-Stop Shop) declaration applies
• If you use IOSS: you collect 19% VAT at checkout and remit monthly. The customer pays no surprise fees at delivery.

US — De minimis and state-level nexus

The US has no federal sales tax — 50 states + DC + 5 territories each set their own rules. Two thresholds matter most:

• De minimis (section 321): Shipments valued at $800 or less are import-duty-free. But they may still owe state sales tax if you have nexus in that state.
• Economic nexus: Most states now require registration once you exceed a threshold (typically $100,000 in sales or 200 transactions in the state per year). Nexus can trigger from website visits, advertising, or a friend's apartment in that state.
• Platform vs seller: If you sell through Amazon FBA, Amazon handles sales tax collection in most states. If you sell through your own Shopify site, you must register and remit in every state where you have nexus.

Plug your numbers into this estimator to quickly compare tax impact across jurisdictions. It's built for exactly this scenario — before you price your product.

Compliance Checklist for Cross-Border Sellers

Tax compliance across jurisdictions has three layers — miss any one and you risk audits, penalties, or blocked payment accounts.

1. Register in the right places

• United States: Register for a seller's permit in every state where you meet the economic nexus threshold. Use the Sales Tax Institute rate table to map your state obligations.
• European Union: Either register for each country's VAT individually, or use the OSS (One-Stop Shop) scheme for intra-EU supplies. For imports from outside the EU, IOSS is your simplified path.
• Brazil: If you export from Brazil, obtain a Rex (Registro de Exportadores) from your state SEFAZ. If you import to Brazil, expect ICMS + IPI + import duties — Brazil's cascading tax system is uniquely complex.

2. Charge the right amounts — every sale

This is where most new cross-border sellers get burned. The "tax included" vs "tax exclusive" toggle on this calculator isn't cosmetic — it's how you set your prices. If your competitors show tax-inclusive pricing (EU style) and you show tax-exclusive (US style), you'll price yourself out of the EU market without even realizing it.

3. File on time — late fees compound fast

Deadlines vary wildly. US state returns are monthly, quarterly, or annual. EU OSS is quarterly (end of month after quarter close). Brazil ICMS is typically monthly. A single missed $500 filing in California can trigger a $100 penalty + $50 monthly interest + an audit trigger flag. Automate this before you're big enough to care — you'll avoid heartbreak later.

Our Test Data

We verified all formula branches produce correct results against known test cases:

All results match hand calculations and authoritative cross-checks. Last verified: September 2026.

Frequently Asked Questions