Each AdWords API operation performed consumes a certain number of API units, as specified in the rate sheet below. Costs are charged at a rate of US$0.25 (or local currency equivalent) per thousand API units.
Operations are charged either per call or per item:
Per call: Cost is constant. For example, getAccountInfo consumes 1 API unit per call.
Per item: Cost is (cost per item × number of items operated upon). For example, a call to updateAdGroupList (which costs 10 API units per item) with an AdGroup array of length 20 would consume 200 API units.
Per-item operations count the items operated upon in one of the following ways:
Length of array passed in. For example, addAds counts the Ad objects passed in.
Length of the returned array. For example, getClientAccounts counts the strings (login emails) returned. If a request both accepts and returns an array, it counts the items only in the larger array.
Number of inner objects operated upon. For example, estimateAdGroupList counts the inner KeywordRequest objects in the AdGroupRequestp[] parameter (each AdGroupRequest has an array of KeywordRequest objects).
If a batch operation (like updateAdGroupList) fails, you are charged only for elements that caused the operation to fail. None of the elements will be processed.
Operation Costs
Because AdWords API v2009 operations are more resource-efficient to process, we've lowered the cost of frequently used operations by approximately 20%.
v2009 Rates
Setting the validateOnly request header to true will reduce the cost of the request to 0.05 API units per item, rounded up to the nearest integer.