By Joe Wiesenfelder, Cars.com

Gas prices remain volatile, but even so, no one expects prices below $3 per gallon ever again, and many parts of the country consistently see prices near or above $4. As much as ever, shoppers need to know how effectively hybrids deliver efficiency for your dollar — if they do at all.

To determine if a hybrid’s added expense is worth the cash, we devised an efficiency-cost rating to reflect efficiency bang for your overall buck.

It’s simply the combined city/highway mpg divided by the base price (MSRP plus destination charge). We then multiply that number by 1,000. This formula can be applied to any type of vehicle, hybrid or not. A high mpg rating and low price provide a high efficiency-cost rating. A higher score is the better score.

We don’t account for equipment levels, quality judgments, cost of ownership or any variances from EPA mileage estimates. The goal here is to pay the least for the most mileage, barring all other considerations.