A new Web site lets you calculate your gas costs for any trip: Moblu.

Enter your departure and arrival cities—plus the year, make and model of your car—and Moblu will provide your estimated fuel costs and climate impact along with printable Google Maps directions.

For example, on a trip between Dallas and Denver, Moblu predicts that you'll cover 879 miles. Assuming you're in a 2007 Ford Escape 2WD, you'll burn through 31 gallons of fuel at an average cost of $57 total. Your climate impact will be to produce 618 pounds of carbon dioxide (CO2). That amount of C02 would take 16 tree seedlings grown for 10 years to absorb from the atmosphere, according to the site.

You don't have to sign up for anything to take it for a test spin. Moblu can also be used to track the fuel economy of your car, but you need to sign up with the service : as well as join Twitter* to take advantage of that feature, notes The New York Times' blog Wheels.)

*Blog post clarified after publication, due to comment posted below.

MORE
Check out Budget Travel's dozens of tested road trip itineraries and One-Tank Escapes.

If you feel guilty about the environmental damage, you can click a link to buy a carbon offset. See our article Are Carbon Offsets Worth It?

EARLIER
Condo-or-Hotel Deal Calculator: A new tool from TripAdvisor will help you decide if a hotel or a rental will be the most cost-effective lodging option for you