I know there are a number of variables, but is there a calculator that looks at a particular TV weight and TT weight and takes a guess wild guess at what an approximate MPG would be? It ought to take into account whether you are using gas or diesel.

10 mpg is a good ballpark number. That's if you hold your speed to 60 and don't have a significant headwind. I've seen as low as 7 and as high as 14. But for budget purposes, we work with 10 mpg.

No there isn't. 10 is about the norm, some as little as 6, 12 if your pulling a popup. The weight of the TT doesn't matter as much as the speed you travel and the "frontal area". A larger TT then the one you have now won't make much difference unless it is a 5er with a larger frontal area.

There are far too many variables to easily calculate this. Average is 10. I get 10 with my current combo. I previously towed this trailer with a 2003 Trailblazer and I got 8. The same Trailblazer with a 17 ft hybrid and I got 11.

Try dividing the gasoline used into the miles driven using an old school adding machine. Works every time.

I use calculator...miles divided by gallons, each fillup. At end of trip total miles div. By gallons for trip average. Gas 2500, Avg 9.5, towing only..gas motorhome, Ford V-10 always seemed to be 8.0. Doesn't seem to matter uphill, downhill. Tail wind will give a tad better on a fillup, headwind wind a little less. Speed 55-60.

Is there a calculator that can approximate the expected MPG

APT
Explorer
Aug 09, 2016
Budget 8mpg gas towing any high walled RV.
Budget 10mpg diesel towing any high walled RV.

You may get slightly better, but you will be much happier budgeting for 8 and getting 9 than budgeting for 10 and getting 9.

Weights do not matter (much). Every hill you go up you come back down. The fuel cost is for the aerodynamic drag at 65mph.
Bird_Freak
Explorer II
Aug 08, 2016
Try a crystal ball.
valhalla360
Navigator
Aug 08, 2016
The old 7.3 diesel averaged just shy of 13mpg but as low as 9mpg (into a 25mph headwind) and as high as 16mpg (30mph tail wind).

The new V10 doesn't have as many miles on it but seems to be running around 9mpg.

Way to much variation in rigs and how you drive to give a good estimate.
Old-Biscuit
Explorer III
Aug 08, 2016
MH........SWAG is 6 mpg
Truck,,,gas.....SWAG is 8 mpg
Truck,,,diesel.....SWAG is 10mpg
mkirsch
Nomad II
Aug 08, 2016
Captain_Happy wrote:
Try dividing the gasoline used into the miles driven using an old school adding machine. Works every time.

0/0 = UNDEFINED

He is looking for a caculator to *PREDICT* the fuel economy of a yet-to-be-determined rig.
donn0128
Explorer II
Aug 08, 2016
Down load the smart phone app, gas logger. Works great to give you cost and MPG for each fill up.
coolbreeze01
Explorer
Aug 08, 2016
You can expect over 6mpg and less than 16mpg.
monkey44
Nomad II
Aug 08, 2016
We just did 7500 miles and averaged 10.7 about half of it in the Rockies. That's derived from gallons bought and odometer miles.
SoCalDesertRid1
Explorer
Aug 08, 2016
There are too many variables for even the same truck and same trailer to get the same mpg driving on the same road, when driven by different drivers. The driver has alot to do with the mpg. Then start trying to compare completely different trucks, trailers, roads and drivers all together and that's just a big mess that you really can't get any reliable data from.
SouthpawHD
Explorer
Aug 08, 2016
OP,what are you trying to accomplish? You've been around here long enough to know that RVing isn't an MPG friendly hobby. So curious as to why you are asking.