Unit Pricing Measure [unit_pricing_measure] and Base Measure [unit_pricing_base_measure] Fields for Product Feed

Optional but Required Together for Products Sold by Weight, Volume, or Unit

The unit_pricing_measure and unit_pricing_base_measure attributes define the total product quantity and the reference base quantity used to display a product’s price per unit.
These attributes help users understand value-for-money comparisons, for example, cost per liter, gram, or item in both ChatGPT and Google Shopping.

They are especially useful for grocery, hardware, cosmetics, office supplies, or materials sold by weight, volume, length, or area.

When to use

Use these fields if:

• You sell products typically priced by weight, volume, or quantity (e.g., beverages, perfume, flooring).

• Your country or market requires unit price display (such as the EU, EFTA, UK, Australia, or New Zealand).

• You want ChatGPT or Google to calculate and show price per standardized unit (e.g., $2.50 per 100ml).

• Both [unit_pricing_measure] and [unit_pricing_base_measure] must:

  • Be submitted together.
  • Include a positive numeric value and a unit.
  • Use consistent units and rounding (max 2 decimals).
  • Follow ISO-compliant units (see below).

ChatGPT Specification

✅ ChatGPT uses these fields together to display price per unit and improve AI understanding of relative product value.

Example Calculation: If price = 3 USD, unit_pricing_measure = 150 fl oz, and unit_pricing_base_measure = 100 fl oz,
→ Unit Price = 2.00 USD / 100 fl oz

Google Merchant Center Specification

Purpose

Google’s unit_pricing_measure and unit_pricing_base_measure serve the same purpose, helping display cost per unit across Shopping ads and free listings.

⚠️ Required in regions where unit price disclosure is mandatory (EU, EFTA, UK, Australia, New Zealand).

Accepted Format

• Type: Positive number + unit
• Decimal precision: Up to 2 digits (automatically rounded).
• Repeated field: No
• Schema.org property: Offer.priceSpecification.referenceQuantity
• File format:
  • Text feed → 750ml
  • XML feed → <g:unit_pricing_measure>750ml</g:unit_pricing_measure>

Supported Units

For the UK, use metric values only (imperial units like “fl oz” are interpreted as US).
In New Zealand and Australia, sheet and item are also accepted.

Examples:

Relationship Between the Two Fields

Both fields must be provided together:

Google and ChatGPT interpret these fields the same way : one describes the total quantity, the other the reference base for computing the unit price.

Example: Price: 5 USD unit_pricing_measure: 500 ml unit_pricing_base_measure: 100 ml → Unit Price = 1.00 USD / 100 ml

Minimum Requirements

Note: Omitting one of the two attributes will prevent unit price calculation.

• Submit both fields together (unit_pricing_measure + unit_pricing_base_measure).
• Use valid measurement units (see supported list).
• Limit decimals to 2 digits.
• Don’t mix incompatible units (e.g., ml vs. oz).
• Don’t submit text descriptions (“one bottle”, “full pack”).

SEO / AI Tip

Providing unit_pricing_measure and unit_pricing_base_measure helps ChatGPT and Google clearly display price-per-unit information in listings and comparisons.
This transparency improves user trust, conversion rates, and compliance with regional price-labeling regulations.

Official Sources:

• ChatGPT Product Feed Specs
• Google Merchant Center – Unit Pricing Measure
• Google Merchant Center – Unit Pricing Base Measure