Currency & values

Default currency

EUR for Biosphere (unless you add international markets).

Always include currency on monetary events:

ecommerce: {
  currency: 'EUR',
  value: 84.00,
  /* ... */
}

ISO 4217 format

3 uppercase letters: 'EUR', 'CHF', 'USD', 'GBP'. Not the symbol ('€' is invalid), no lowercase.

How to compute value

value = Σ (item.price × item.quantity) − global order coupons

Without shipping or tax on add_to_cart, begin_checkout, view_cart, etc. The purchase event includes shipping and tax as separate fields.

Example

Cart:

• Cream 42€ × 2 = 84€
• Serum 35€ × 1 = 35€
• Promo code -10€

{
  event: 'view_cart',
  ecommerce: {
    currency: 'EUR',
    value: 109.00,                    // 84 + 35 - 10
    coupon: 'SPRING10',
    items: [
      { item_id: 'BIO-CRM-001', item_name: 'Cream', price: 42.00, quantity: 2 },
      { item_id: 'BIO-SER-001', item_name: 'Serum', price: 35.00, quantity: 1 }
    ]
  }
}

On purchase, send shipping and tax separately (and value stays the merchandise subtotal):

{
  event: 'purchase',
  ecommerce: {
    transaction_id: 'ORD-2026-00123',
    currency: 'EUR',
    value: 109.00,        // merchandise
    tax: 18.17,
    shipping: 4.95,
    coupon: 'SPRING10',
    items: [ /* ... */ ]
  }
}

GA4 convention: value = merchandise revenue. Total paid = value + tax + shipping. This is what GA4 and Meta use to compute ROAS.

Number formatting

• Always number, never string: 42.00 ✅ — "42.00" ❌
• Period decimal separator, not comma: 42.00 ✅ — 42,00 ❌
• No thousands separator: 1299.50 ✅ — 1,299.50 or 1 299.50 ❌
• Max 2 decimals (GA4 rounds beyond).
• Always units, not cents: 42.00 €, not 4200.

Cents → units conversion

If your backend stores prices in cents (Stripe-style), convert before push:

function toAmount(cents) {
  return Math.round(cents) / 100;
}
// price: toAmount(4200) → 42.00

Cart consistency

GA4 will show discrepancies if:

value ≠ Σ (item.price × item.quantity)

Tolerance: ±1 cent. If rounding makes this messy, normalize backend-side before pushing.

Tax: included or excluded?

Convention for Biosphere (confirm with the agency):

• price and value: VAT included (matches what the customer sees on-site).
• tax: amount of VAT contained in the total.
• shipping: shipping fee, VAT included.

Stay consistent with the customer's invoice.