How do I fix “Required parameter ‘value’ is missing for event ‘Purchase’”?
Short answer
Meta shows this when a Purchase event arrives with no value, or with a value it can’t read, such as a formatted price like $49.99. It usually means a second Purchase event is firing from code or a rule that doesn’t carry the order total, so the fix is to find and remove that extra source.
Why it happens
- A second Purchase with no data. The official app sends value and currency. A Purchase pasted into theme code or created with Meta’s Event Setup Tool often doesn’t.
- A formatted price. Value must be a plain number, such as 49.99. Text like $49.99 or 1,299.00 shows as “Parameter ‘value’ is invalid for event ‘Purchase’”.
- A missing or wrong currency. Currency must be a three-letter code such as USD or GBP. A symbol shows as “Parameter ‘currency’ is invalid for event ‘Purchase’”.
- Purchase firing on the wrong page. A Purchase that fires on a normal page has no order to take a value from.
How to fix it
- Read the exact warningOpen the page with the Meta Pixel Helper, or the browser console, and note which message appears: missing, invalid or negative value, or missing or invalid currency.
- Check DiagnosticsIn Events Manager, open your dataset › Diagnostics to see which event and which parameter Meta flags, and since when.
- Find every Purchase sourceSearch your theme for “Purchase” and “fbq(”. On Shopify, check Settings › Customer events. In Events Manager, open the Event Setup Tool and look for a Purchase created there.
- Remove the extra sourceKeep the official app or your one tracking plugin as the only Purchase sender, and delete the rest.
Check it worked
Place a test order with the Pixel Helper open. You should see one Purchase with a numeric value and a three-letter currency, and no warnings.
Common questions
Does this warning affect my ads?
Yes. Campaigns that optimise for purchase value or report ROAS need the value. Events without it can’t be used for those.
Why does it only mention Purchase?
The pixel’s console checks are strictest on Purchase. Other events can have the same formatting problem without a warning.
How long until Diagnostics clears?
Meta re-checks over the following days. The warning should stop once new events arrive correctly.
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