Do hybrids save money? Website lets you calculate it.

Hybrid vehicles cost more upfront than comparable gasoline models, but get better fuel economy.

So will you save money in the long run?

To make the comparisons easier and more accurate, the FuelEconomy.gov site has launched a new comparison tool that provides a "Years to Payback" number based on the manufacturer's quoted base prices and the EPA gas-mileage ratings for comparable hybrids and non-hybrids.

The important factor here is that the tool attempts to compare models with similar equipment and features--a factor often ignored when comparing a hybrid's price to the least expensive base model of a comparable gasoline vehicle.

As regularly noted--and criticized by the Union of Concerned Scientists and others--hybrid models are usually very well-equipped, with features and equipment as part of their standard price that are optional and cost more on comparable gasoline models.

The new comparison tool can be found by clicking on the "Hybrids Can Save You Money" menu option.

In the first step, the user selects from a list of 18 hybrid models, including both dedicated hybrids (like the various models of the Toyota Prius range) and hybrid models of conventional cars. The list includes mild hybrids like the Honda Civic Hybrid as well as full hybrids like the Ford Fusion Hybrid.

Then the user customizes the calculations by specifying annual miles covered, what percent of those miles are city driving, and the price of fuel to be used for calculations.

Instantly, the calculator shows the difference in list prices and the payback period based on those figures.

Not surprisingly, hybrids pay back quicker if annual miles covered and/or fuel cost rises.

The 2012 Ford Fusion Hybrid offers a good example. Its base price is $29,570, and the calculator compares it not to the lowest-priced Fusion (at $20,705), but the Fusion SEL model that has the mix of features and options closest to those on the hybrid.

The Fusion SEL's base price is $26,220--providing the most realistic, apples-to-apples comparison.

Ah, you say, but I don't really want all those fancy features. I just want a bare-bones hybrid.

That may be true, but that's not the Fusion Hybrid that Ford will sell you. And until the company changes its equipment levels--which we suspect won't happen any time soon--the new calculator attempts to compare cars with equivalent features.

It's worth noting that while Toyota sells a Prius One trim level, essentially a stripped-down model, it's not available to retail buyers. It's solely for fleet purchases. The choice of Prius trim levels for regular consumers starts with the Prius Two.