An overview of the general cost of living index for Ontario, CA is displayed above for your reference. Residents in Ontario, CA enjoy a cost of living index of 119. This index is 12% lower than the California average, and 19% higher than the national average. The following categories are used when determining the cost of living index for any given city: health care (5%), transportation (9%), utilities (10%), groceries (13%), housing (30%), and goods/services (33%). Clearly, housing and goods/services make up the majority of the formula for calculating the cost of living index. Because of this, the general cost of living for any given area can be estimated by looking at the cost of everyday goods in that area. For those living in Ontario, CA, the average cost of goods and services is 3% lower than it is in California, and it is 4% higher than the national average.