Fly vs Drive Calculator™ FAQ

Why use it?

The BeFrugal Fly or Drive Calculator™ is a great way to help plan road trips and summer vacations. For any travel itinerary within the continental US, the calculator will provide useful estimates of time and cost of flying versus driving.

How does it work… Flying?

To estimate the cost and time needed to fly, the calculator automatically determines the nearest major airports, travel times to the airports, transit time at the airports, flying times, and costs associated with each part of the trip.

The calculator uses the shortest driving time to determine the nearest major airport from the starting address, and similarly for determining the nearest major airport to the destination.

To estimate flying time, the calculator uses BeFrugal’s proprietary algorithms and databases of airport location data and passenger jet performance.

How does it work… Driving?

To estimate the cost and time needed to drive, the calculator’s trip routing algorithm uses databases of highway maps, driving speeds, automotive operating costs, and an estimated overnight hotel cost of $75/night.

The calculator’s automotive operating cost data is from AAA. This data is an all in cost which includes fuel, maintenance and tires to give a true idea of the cost of driving.

The calculator’s driving time estimate uses travel times for the actual recommended route, and will incorporate overnight stops if necessary.

How accurate is it?

In most scenarios, estimated travel costs and times are accurate enough to be used to decide between flying or driving.

Estimation of flying time is generally accurate to within +/- 10% as long as the preferred travel route utilizes any of the 261 major US airports, and travel is via a passenger jet airplane.

Estimation of ticket prices is generally accurate to within +/-25% as long as tickets are booked two weeks in advance, and travel is outside of peak holidays. The consumer can get actual ticket prices by clicking on the Travelocity link for a quote for their specific itinerary.

Estimation of driving times is generally accurate to within +/- 10% because the calculator uses actual map data and travel times to determine the route and therefore driving time.

Estimation of driving costs is calculated using AAA data and is accurate to within +/- 20% for most types of vehicles.

How is ‘CO2 Impact’ calculated?

For driving, CO2 emissions are calculated at 24.27 pounds of CO2/gal for gas and 27.60 pounds of CO2/gal for diesel. This includes both tailpipe CO2 emissions and upstream CO2 emissions.

For flying, CO2 emissions are calculated at variable levels depending on the flight distance. This CO2 estimates are based on data from the GHG Protocol Mobile Combustion Tool. A Radiative Forcing Index of 1.9 is also used in this calculation.

Who is BeFrugal?

Launched in February 2009, BeFrugal is a website focused on frugal living, and features coupons, deals and bargains, as well as web-based tools to help consumers save money.

BeFrugal’s other calculators have been featured widely – including on,, and the Discovery Channel.

BeFrugal’s 300% growth in the last year made it one of the fast growing websites that feature online coupons. Currently, BeFrugal features 100,000 coupons for over 10,000 online stores.


5 Comments on “Fly vs Drive Calculator™ FAQ”

  1. Amanda Says:

    I was curious how you selected your airports. I’m from Spokane and the Spokane International Airport (GEG) isn’t on your list. It’s not just a municipal airport; it handles a lot of traffic and flies all over the country. Anyhow, it would be super helpful to see this information! Thanks.

  2. John Says:

    Going from Minneapolis to Lansing, you either have us driving through Lake Michigan or else taking the ferry but not including the cost.

  3. Michele Says:

    There is no way the calculator is right we just did a trip from fl to ny and kept track of the costs the gas was right on the money but it goofed when it came to tolls it told us 4,000 dollars that was a tad bit high it really was 34.00 i just think the calculator goofed everything else was pretty close I think someone should look into that because if people from another country were to look at that and depend on it they would be told a wrong number thanks

  4. Tammy Says:

    many sites offer you to put in the mileage of YOUR OWN car/vehicle. That would be more realistic. And enter the price per gallon on average if you know it.

  5. julie Says:

    Just wondering what the price of gas is when you figure the cost of driving?