Conversion value is zero or missing: where the problem is

A conversion is counted, but with no value — or zero. Ads then see the number of purchases, not revenue, and can't optimize for turnover or profit. The cause is almost always in the data layer, not the platform connection.

Symptoms

• Conversions exist in GA4 / Meta / Google Ads, but their value is 0 or empty.
• The conversion count is right, but total revenue isn't.
• Value-based bidding strategies (tROAS) don't work.

Why it happens

• The value isn't passed into the data layer at all on the purchase event.
• The value is text instead of a number — e.g. "$12.90" instead of 12.90. The platform can't sum such a value.
• Currency is missing (currency), so the value can't be interpreted correctly.
• Wrong mapping in the tag — the value is read from a nonexistent or renamed field.

How to fix it

• 1. In GTM preview mode, check whether the purchase event in the data layer even carries value and currency.
• 2. Verify value is a number, not text — no currency, spaces or symbols.
• 3. In GA4 DebugView, confirm the value reaches Analytics.
• 4. Fix the mapping in the tag if the value is in the data layer but doesn't reach the platform.

Why a clean data layer is the basis of all measurement is explained in the data layer: foundation of good measurement. For the general verification routine, see how to verify server-side tracking works.