OSS / IOSS VAT simulator for e-commerce 2026: 27 EU country matrix
Model your e-commerce VAT country by country with the 27 EU 2026 standard rates, the 10,000 € OSS threshold, IOSS and marketplace responsibility.
27 EU 2026 standard rates pre-filled and overridable per line.
10,000 € OSS threshold computed on the actual cross-border total (excluding France and marketplace).
Alerts for IOSS ≤ 150 €, marketplace-collected VAT, foreign stock and returns.
OSS / IOSS VAT is as operational as it is tax-related
In e-commerce, VAT depends on customer country, stock location, marketplaces, refunds and data quality. The one-stop shop simplifies some filings, but it does not fix poor transaction classification.
OSS
OSS can centralise some VAT declarations due in other EU Member States for cross-border B2C sales.
- Monitor the 10,000-euro threshold for relevant EU B2C sales.
- Split sales by country of consumption.
- Reconcile platform exports with back-office and accounting.
IOSS
IOSS concerns certain distance sales of low-value imported goods. It requires clear flow identification and responsibility mapping.
- Separate import, local delivery and marketplace sale.
- Track refunds, returns and corrections.
- Check the role of intermediary or platform.
Reconciliation
The calculation must be reconciled with Shopify, Amazon, Stripe, ERP, customs and accounting exports. That is often where gaps appear.
- Control average rates and actual countries served.
- Separate exempt, cancelled or refunded sales.
- Document assumptions before filing.
Data to control
A reliable e-commerce VAT simulation starts from transaction data, not only global revenue.
- French sales, EU B2C sales by country and low-value imports.
- VAT rates applied, refunds, credit notes and returns.
- Stock location, marketplace responsibility and country of consumption.
- Differences between back-office, payment, invoicing and accounting data.
Hayot Expertise analysis
We treat e-commerce VAT as a data issue: platform exports, consumption country, credit notes, refunds and bank reconciliation. An average rate is only an indicator; filing requires robust country-level data.
The underestimated risk
The main risk is reporting VAT that looks plausible but is based on misclassified data: wrong country, marketplace responsibility, foreign stock or unallocated refunds.
What the e-commerce founder must decide
- Which flows belong to France, OSS, IOSS or local obligations.
- Which system becomes the source of truth for VAT.
- Which monthly reconciliation process to follow.
- When to audit marketplace and international sales.
2026 watchpoints
- Monitor the OSS threshold and sales by country of consumption.
- Check stock, fulfilment and marketplace responsibility.
- Process returns and refunds before filing.
- Keep transaction evidence and exports.
OSS / IOSS VAT FAQ
Does the 10,000-euro OSS threshold apply to all revenue?
No. It concerns specific EU B2C cross-border sales. French sales, B2B sales and some marketplace flows must be analysed separately.
Does IOSS remove all customs formalities?
No. It facilitates certain low-value flows, but operation qualification and customs obligations still need monitoring.
Why does foreign stock trigger an alert?
Because stock held in another country may create local VAT or reporting obligations that are not solved by OSS alone.
Do marketplaces always collect VAT for the seller?
Not always. Their role depends on the flow, country, goods and contract. Detailed platform reports must be reviewed.
Can the simulator prepare the OSS return?
No. It provides an estimate. Filing must be based on country-level data, corrections and evidence.
Official sources
Updated for 2026 EU rates. Results are indicative and must be reconciled with detailed country-level exports before filing.
Go further
Is e-commerce VAT getting hard to track?
We can audit Shopify, Amazon, Stripe or ERP flows and secure French VAT, OSS and IOSS allocation.