Hybrid technology is spreading to both cars and SUVs, but in most cases you’ll pay dearly for the privilege of electric assist, and all hybrids are not created equally.

Using our owner cost estimates, we checked out the actual cost of owning a hybrid over time. Of the seven hybrids we recently tested, we found that three, the Toyota Prius, Toyota Camry Hybrid, and Honda Civic Hybrid, save owners money compared with their all-gas alternatives, while others depend on tax breaks to break even. Overall, hybrid costs range from $4,250 in savings to a $1,750 deficit over five years, compared with their most similar gas counterparts. The Toyota Prius costs thousands more to buy than either the Toyota Corolla or the Toyota Matrix, but it costs less to own than either: $250 less than the Corolla, and $4,250 less than the Matrix 2.4.

The four-cylinder Toyota Camry XLE and Camry Hybrid cost about the same to buy. The Hybrid gets 34 mpg overall versus 24 mpg for the non-hybrid Camry.

More expensive hybrids with smooth, powerful V6 engines, such as the Lexus RX 400h and the Toyota Highlander cost hundreds more to own over five years than their gasoline counterparts, even though they save thousands of dollars in fuel costs.

Hybrids’ fuel savings are real, however. The base Prius delivered an excellent 44 mpg overall, the highest of any five-passenger vehicle we have ever tested. The Toyota Highlander Hybrid, which achieved the best fuel economy of any current SUV we’ve tested, can save you nearly $700 per year in gasoline costs, compared with the V6 model.

For more information on hybrid vehicles, see How hybrids work. To learn about alternative fuels and fuel economy, see our Guide to driving green.