Google Shopping Unit Pricing Base Measure Attribute: Requirements & Examples

What is the unit_pricing_base_measure attribute?

The unit_pricing_base_measure attribute defines the reference denominator for the per-unit price that Google calculates and displays in Shopping results. It works together with unit_pricing_measure (the actual quantity in the package) and your price to produce a standardized comparison price. Google’s formula is: displayed unit price = price ÷ unit_pricing_measure × unit_pricing_base_measure.

If your 750ml shampoo costs €14.99 and you set unit_pricing_base_measure=100ml, Google calculates €14.99 ÷ 750 × 100 = €2.00 per 100ml. This enables shoppers — and increasingly, Google’s own sorting systems — to compare the true value of identically-categorized products regardless of package size. The base measure is not just a display preference; in regulated markets it’s a legal specification tied to the EU Price Indication Directive’s mandated reference quantities.

Technical specifications

Where it displays

• Shopping Ads — The base measure defines the denominator of the per-unit price shown in Shopping ad listings. This is displayed as a smaller line below the main price (e.g., “€2.00 / 100ml”). The base measure you choose determines how that line reads — and whether it’s comparable to what shoppers see for competing products.

• Free Listings — On the Shopping tab, per-unit prices are displayed on the product detail page. In markets with legal unit pricing requirements, this is prominently placed and may be a factor in Google’s free listing ranking for price-sensitive categories.

• Shopping tab comparison — When Google surfaces a price comparison module (showing multiple sellers for the same product), the per-unit price derived from this attribute enables apples-to-apples value comparison. Products that use standard base measures are more likely to be correctly grouped and compared.

• Display & Remarketing — Unit pricing attributes are available as product-level signals in Dynamic Remarketing campaigns, contributing to price-per-unit targeting for value-focused audience segments.

Rules

• Always submit with unit_pricing_measure — These attributes are a required pair. Neither works in isolation.

• Same physical dimension as unit_pricing_measure — If the measure is in volume (ml), the base measure must also be volume (ml, cl, l). Mixing dimensions is a feed error.

• Use standard reference quantities — Especially for EU/UK markets, use the officially mandated reference quantities (see table below) for your category. Unusual base measures (e.g., 250ml instead of 100ml) produce per-unit prices that shoppers cannot easily compare against the rest of the market.

• No space between number and unit — 100ml correct; 100 ml incorrect. The format is strict.

• Exact unit abbreviations — Use the lowercase abbreviations exactly as documented. g not grams; ml not mL.

Best practices

EU-mandated standard base measures by category

The EU Price Indication Directive specifies which reference quantities must be used per product type. Google’s implementation follows these standards for EU market feeds:

Matching competitors’ base measure

Even if you’re outside legally mandated markets, using the same base measure as your direct competitors allows Google to surface a consistent comparison. If the 3 main competitors all show “per 100g” for matcha powder, use 100g — not 1kg or 50g. A shopper comparing “€12.50 / 100g” vs. “€0.13 / g” cannot easily judge value, even if the math is equivalent.

The math behind the display

Understanding the calculation helps you verify your setup is correct before submitting:

• Product: 1.5l olive oil at €8.99

• unit_pricing_measure=1500ml, unit_pricing_base_measure=100ml

• Calculation: €8.99 ÷ 1500 × 100 = €0.60 / 100ml

• Displayed: “€0.60 / 100ml”

Always verify the output price makes sense in context. A €0.60 per 100ml olive oil is plausible; €600 per 100ml would indicate an error in the measure attribute (e.g., unit_pricing_measure=1.5ml instead of 1500ml).

Impact on performance

• Legal compliance in regulated markets — Without a correct base measure, your unit pricing pair is incomplete and non-compliant in EU/UK/AU. Products in covered categories may be disapproved or demoted in these markets.

• Comparison shopping conversion — Shoppers in FMCG, food, and personal care categories heavily rely on unit pricing for purchase decisions. Providing clear, correctly normalized per-unit prices reduces the cognitive friction of comparison and benefits retailers whose products offer genuine per-unit value.

• Trust and listing quality — Incorrect or misleading unit pricing (e.g., using an unusual base measure that makes your product look cheaper than it is) damages brand trust and may be flagged by Google’s quality systems. Accurate unit pricing builds trust with price-literate shoppers.

• Feed health score — Complete attribute pairs for required fields improve your overall Merchant Center feed health score, positively influencing listing visibility.

Common mistakes

• Submitting unit_pricing_base_measure without a corresponding unit_pricing_measure (or vice versa)

• Using a non-standard base measure (e.g., 250ml) that doesn’t match category convention

• Mixing dimensions between the two attributes (e.g., measure in ml, base in g)

• Confusing the measure attribute (product quantity) with the base measure attribute (reference unit) — they serve different roles

• Setting both attributes to the same value when the product quantity equals the base measure — this works but is rare and should be verified

• Using 1l as a base measure for a product category where 100ml is standard, producing a price that looks 10× more expensive than competitors when it isn’t

• Forgetting to update the pair when launching new pack sizes under the same product family

Pro tips

• Build a category → base measure mapping table in your feed system — Define the correct base measure for each product category at the system level, not per-product. This ensures consistency across your entire catalog without requiring per-SKU decisions, and makes compliance audits trivial.

• Create a validation check in your feed pipeline — Before publishing, verify that: (a) both attributes are present whenever either is present, (b) both use the same physical dimension, and (c) the calculated per-unit price falls within a plausible range for the category. Automated validation catches data errors before they become compliance issues or disapprovals.

• Use a supplemental feed for rapid unit pricing deployment — If your main feed doesn’t include unit pricing, a supplemental feed with id + unit_pricing_measure + unit_pricing_base_measure can deploy unit pricing across your full catalog within one feed refresh cycle — no main feed rebuild required.

• Cross-reference against GMC feed diagnostics after deployment — After adding unit pricing, check Merchant Center’s Product issues for warnings related to unit pricing format or dimension mismatches. The diagnostics will flag any products where the pair is inconsistent or uses unsupported unit formats, allowing targeted fixes before the issues scale.